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Cimetidine has been shown to have beneficial effects in colorectal cancer patients. In this study, a total of 64 colorectal cancer patients who received curative operation were examined for the effects of cimetidine treatment on survival and recurrence. The cimetidine group was given 800 mg day(-1) of cimetidine orally together with 200 mg day(-1) of 5-fluorouracil, while the control group received 5-fluorouracil alone. The treatment was initiated 2 weeks after the operation and terminated after 1 year. Robust beneficial effects of cimetidine were noted: the 10-year survival rate of the cimetidine group was 84.6% whereas that of control group was 49.8% (P<0.0001). According to our previous observations that cimetidine blocked the expression of E-selectin on vascular endothelium and inhibited the adhesion of cancer cells to the endothelium, we have further stratified the patients according to the expression levels of sialyl Lewis antigens X (sL(x)) and A (sL(a)). We found that cimetidine treatment was particularly effective in patients whose tumour had higher sL(x) and sL(a) antigen levels. For example, the 10-year cumulative survival rate of the cimetidine group with higher CSLEX staining, recognizing sL(x), of tumours was 95.5%, whereas that of control group was 35.1% (P=0.0001). In contrast, in the group of patients with no or low levels CSLEX staining, cimetidine did not show significant beneficial effect (the 10-year survival rate of the cimetidine group was 70.0% and that of control group was 85.7% (P=n.s.)). These results clearly indicate that cimetidine treatment dramatically improved survival in colorectal cancer patients with tumour cells expressing high levels of sL(x) and sL(a)., (Copyright 2002 The Cancer Research Campaign)

This study assessed the duration of action of single doses of ranitidine (75 mg), cimetidine (200 mg), or placebo on intragastric acidity in healthy subjects. When dosed with placebo, mean daytime intragastric acidity (0-10 hr after dose) was 37.62 mmol/liter, decreasing to 17.21 mmol/liter (mean decrease 59%; P < 0.001 vs placebo) and 25.06 mmol/liter (mean decrease 35%; P < 0.001 vs placebo) when treated with ranitidine and cimetidine, respectively. Ranitidine inhibited intragastric acidity to a greater degree than cimetidine (P < 0.001). Mean nighttime (10-20 hr after-dose) intragastric acidity when dosed with placebo was 34.37 mmol/liter, decreasing to 29.06 mmol/liter (mean decrease 18%; P = 0.027 vs placebo) when dosed with ranitidine and remaining virtually unchanged at 33.85 mmol/liter (mean decrease 2%; NS vs. placebo) when dosed with cimetidine. Ranitidine inhibited acidity to a greater degree than cimetidine (P = 0.043). The inhibitory effect of ranitidine, 75 mg, on intragastric acidity can be detected from 0-15 hr after an oral dose. Cimetidine 200 mg has little inhibitory effect beyond 10 hr.

Purpose: Dexamethasone and histamine antagonists have been employed commonly as premedications for prophylaxis of hypersensitivity reactions (HSRs) to paclitaxel. Frequent premedications for weekly administration of paclitaxel are associated with added side-effects and extra cost. We analyzed our experience of HSRs to paclitaxel administered every 3-4 weeks, and designed a treatment algorithm to eliminate premedications in a majority of patients receiving weekly paclitaxel., Patients and Methods: The incidence of HSRs was analyzed retrospectively in patients who received 3-hr infusions of paclitaxel (135-225 mg/m2) every 3-4 weeks in our institution over a period of 5 years. On the basis of the results of this analysis, we designed a premedication schema for patients receiving weekly paclitaxel, 50-90 mg/m2/week, as follows: Thirty minutes prior to the first weekly dose of paclitaxel, patients received intravenously (i.v.) dexamethasone (10 mg), diphenhydramine (25 mg), and cimetidine (300 mg). If no HSRs occurred, all premedications were deleted for subsequent weekly paclitaxel doses. For patients who experienced HSRs, 20 mg of dexamethasone was given orally 12 and 6 hr prior to re-challenge with paclitaxel in addition to diphenhydramine and cimetidine., Results: Over a period of 5 years, 358 patients received 1608 3-hr infusions of paclitaxel (135-225 mg/m2). Hypersensitivity reactions, which occurred exclusively during the first cycle of paclitaxel administration, were observed in 14 patients. Of these 14 patients, 11 were successfully retreated with paclitaxel without HSRs, two had recurrent HSRs upon paclitaxel re-challenge, and one refused further treatment. These observations indicate that HSRs to paclitaxel occurred in 4% of patients upon first exposure, that most of these patients can be retreated successfully with paclitaxel without recurrent HSRs, and that if no HSRs occur during the first cycle, HSRs are unlikely to occur with subsequent paclitaxel administration. The premedication schema was applied to 30 patients receiving 205 one-hr infusions of weekly paclitaxel. Using this premedication strategy, no HSRs have been observed during the initial or subsequent administration of paclitaxel., Conclusion: We conclude that this premedication strategy is feasible and worthy of further study for patients receiving weekly paclitaxel.

Aims: To examine the effect of concomitant cimetidine or antacid administration on the pharmacokinetic profile of sildenafil citrate in healthy male volunteers in two open-label, randomized studies., Methods: The first study was a parallel-group design in which 22 healthy male volunteers received sildenafil (50 mg) on days 1 and 5 and cimetidine (800 mg) or placebo on days 3, 4, 5, and 6. Blood samples were collected predose and at specified times up to 48 h postdose on days 1 and 5 to determine plasma levels of sildenafil and its metabolite, UK-103,320. The second study was a two-way crossover design in which 12 volunteers received sildenafil with or without a 30-ml dose of a magnesium hydroxide/aluminium hydroxide antacid. Blood samples were collected and analysed as in the first study. The two study periods were separated by at least 14 days., Results: Coadministration of cimetidine had no statistically significant effect on the tmax or kel of sildenafil but caused a statistically significant increase in sildenafil AUCt and Cmax of 56% and 54%, respectively (P<0.01). Differences between the two treatment groups were smaller for the metabolite than for sildenafil, although cimetidine treatment did significantly (P<0.05) increase the AUCt for UK-103,320 by 30%. Antacid coadministration had no statistically significant effect on any pharmacokinetic parameter of sildenafil or UK-103,320. Whether taken alone, with cimetidine, or with an antacid, sildenafil was well tolerated. Most adverse events were mild in nature, and no subject withdrew from either study for any reason related to the drug., Conclusions: Cimetidine co-administration produced an increase in sildenafil plasma levels; however, this increase is not sufficient to warrant dosage adjustment of either drug. Antacid coadministration had no effect on the pharmacokinetic profile of sildenafil.

Background: Cimetidine, which is usually used for gastric ulcer, enhances cellular immunity. The effect of cimetidine on perioperative proinflammatory response after cardiac surgery with cardiopulmonary bypass was investigated., Methods: Elective coronary artery bypass graft cases in which CPB was performed were placed randomly in a cimetidine (C) group (n = 20) or a no-treatment (N) group (n = 20). The time course of plasma levels of neutrophil elastase, interleukin (IL)-6 and IL-8, leukocyte counts, lymphocyte recovery ratio, C-reactive protein, creatine-kinase-MB, and oxygenation index were analyzed., Results: The plasma levels of neutrophil elastase and IL-8 were inhibited in the C groups at 2 hours after CPB termination. In a comparison of the two groups, the C group demonstrated higher lymphocyte recovery ratio and lower C-reactive protein on postoperative day 5 and shorter intubation time. No intergroup differences were observed in IL-6, leukocyte counts, creatine-kinase-MB levels, or oxygenation index., Conclusions: Cimetidine may reduce surgical stress and augment the immune system after cardiac surgery with cardiopulmonary bypass.

Objective: To characterize the change of pH in the abomasal lumen throughout a 24-hour period, to determine whether pH of the abomasal body differs from pH of the pyloric antrum, and to determine whether oral administration of cimetidine and ranitidine alters pH of the abomasal lumen in milk-fed calves., Animals: 5 male dairy calves (4 Holsteins-Friesian, 1 Ayrshire), 5 to 15 days old., Procedure: Cannulas were surgically positioned in the abomasal body and pyloric antrum of each calf. Calves received the following treatments in a randomized crossover design: milk replacer (60 ml/kg of body weight, q 12 h [untreated control calves]), milk replacer and cimetidine (50 or 100 mg/kg, q 8 h), or milk replacer and ranitidine (10 or 50 mg/kg, q 8 h). The pH of the abomasal body and pyloric antrum was measured for 24 hours, using miniature glass pH electrodes., Results: Suckling of milk replacer immediately increased abomasal luminal pH from 1.4 to 6.0, followed by a gradual decrease to preprandial values by 6 hours. Preprandial and postprandial pH values were not significantly different between the abomasal body and pyloric antrum, indicating lack of pH compartmentalization in the abomasum of milk-fed calves. Administration of cimetidine and ranitidine caused a significant dose-dependent increase in mean 24-hour abomasal luminal pH., Conclusions and Clinical Relevance: Abomasal acid secretion in milk-fed calves is mediated in part by histamine type-2 receptors. Cimetidine and ranitidine may be efficacious in the treatment of abomasal ulcers in milk-fed calves.

The permeability of 19 compounds in both the Caco-2/TC7 and HT29-MTX models was determined, and the ability of each model to predict intestinal absorption in humans was compared. Similar apparent permeability values (log P(app)) were obtained in both models for the majority of compounds tested, and plots of log P(app) versus fraction absorbed in humans gave comparable sigmoidal curves. A linear correlation was also observed between the log P(app) values derived from these two models, which suggests that HT29-MTX is an alternative model for absorption prediction in humans. The similarity of both the diffusion coefficients and permeability values obtained for a range of hydrophilic and lipophilic compounds in the two models indicates that the mucus layer secreted by the human adenocarcinoma HT29-MTX goblet cells does not constitute a diffusion barrier to such compounds. The lack of P-glycoprotein (P-gp) in the HT29-MTX cell line may explain the higher permeability values obtained for cimetidine and sumatriptan in this model compared with those derived from the Caco-2/TC7 monolayers. The results suggest that the HT29-MTX model can be used to rank order the passive permeability of compounds, irrespective of their potential interaction with P-gp, which may facilitate optimization of the physicochemical features of compounds within a chemical series., (Copyright 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:1608-1619, 2001)

Rosacea fulminans is a rare disease with female predominance characterized by abrupt onset of pustules, papules, and confluent nodules on the face. The conventional treatment consists of systemic glucocorticoids and isotretinoin. We present the case of a 56-year-old woman with a marked facial papulopustular eruption that had followed an initial period of severe seborrhoea. Conventional treatment produced no clear improvement. Dapsone treatment achieved complete healing in 5 weeks.

A simple method for creatinine determination was developed using high-performance liquid chromatography (HPLC) to more accurately monitor serum creatinine levels in experimental animal models when compared to the Jaffé method. The new HPLC procedure will replace the traditional Jaffé method for rhesus monkey kidney function studies. We developed an isocratic method using a polymeric, hydrophilic, silica-based strong cation-exchange bed with a 5.0 mmol/l lithium acetate matrix, pH 4.9, which isolates creatinine with no detectable impurities as determined by three-dimensional ultraviolet-visible spectral analysis. Sample preparation includes deproteination with acetonitrile, evaporation, and resolubilization in mobile phase followed by quantitation with UV detection at 234 nm. Extraction efficiency across the measured range was 96 +/- 2%. From numerous extracted rhesus monkey creatinine curves (n=38) a slope of 251,100 +/- 756 (95% CI) and an intercept of 675.6 +/- 712.7 (95% CI) was calculated. Extraction efficiency and peak purity tests with human plasma were cross-compared with rhesus monkey serum producing equivalent results. An average of 120 samples can be run daily.

Background: The first step in the management of uncomplicated dyspepsia in primary care often consists of prescribing empirical therapy, but in certain cases prompt endoscopy might be preferred. Any decision is usually based on the patient's symptoms and the presumed underlying pathology that causes these symptoms., Aim: To assess the relationship between symptom subgroups and the effect of management strategies on primary care patients with dyspepsia., Design of Study: Randomised controlled trial., Setting: All patients presenting successively with a new episode of dyspepsia between January 1995 and November 1997., Method: The results of four management strategies in dyspeptic primary care patients were compared and the value of subgrouping within this trial was estimated. Patients were allocated to one of either (a) empirical treatment in which therapy was based on the presented symptoms, or empirical treatment with (b) omeprazole or (c) cisapride regardless of the presented symptoms, or (d) prompt endoscopy followed by the appropriate treatment. Patients were retrospectively classified into the subgroups for each strategy using baseline data. The yield of each strategy was measured by counting the number of strategy failures in the first year., Results: Of the 349 included patients, 326 were analysed. No statistically significant difference could be demonstrated between the strategies or between the symptom subgroups. However, patients in the reflux-like subgroup showed a trend towards a better outcome in all empirical strategies. Ulcer-like dyspepsia seemed to benefit from omeprazole. The non-specific subgroup seemed to benefit from cisapride but also had the highest proportion of strategy failure. Prompt endoscopy did not appear especially useful in any subgroup., Conclusion: Although this study has relatively low power, we conclude that the use of symptom subgroups seems to be a sensible approach when choosing empirical therapy in dyspepsia. Patients with reflux-like symptoms seem to have the best prognosis in the first year in every strategy.

Various immunomodulating agents have been used in the treatment of recalcitrant warts, but none is uniformly effective. Aggressive surgical therapy of warts in children is painful and may require general anesthesia. Drugs such as cimetidine and levamisole have been tried with varying success rates. Given the different target of activities of immunomodulation by cimetidine and levamisole, we questioned whether the combination might be more effective and conducted a double-blind comparative trial of a combination of cimetidine and levamisole versus cimetidine alone. Forty-four patients with multiple recalcitrant warts were assigned to one of two treatment groups (groups A and B) in double-blind fashion. Of the 44 patients, 19 in group A and 20 in group B could be evaluated. At the end of therapy, cure rates (complete clearance) obtained were 31.5% of those in group A and 65% of those in group B (combination treatment). A statistically significant improvement was seen in patients treated with the combination of levamisole and cimetidine (p=0.0150). The rate of regression was faster in group B (average regression period of 7.8 weeks compared with 11 weeks in group A). The present study demonstrated that the combination of cimetidine with levamisole is more effective than cimetidine alone and is a highly effective therapy for the treatment of recalcitrant warts.

This study investigated the use of a combination of H1 and H2 antagonists and topical medications to control burn wound itch. Graeco-Latin square assignment provided an oral combination of 1) cetirizine and cimetidine or 2) diphenhydramine and placebo in four divided doses. The study protocol lasted 16 days divided into 4-day intervals, scoring itch before the initial dose of medication and at 1-hour, 6-hour, and 12-hour intervals after the first medication. A significant difference between mean itch scores across the four times was observed (Wilks' Lambda F = 26.52, df = 3, P <.0005). A three-way nested repeated measures interaction effect (Wilks' Lambda F = 9.85, df = 9, P <.0005) was observed representing a significantly different pattern on days 1 to 4 of the study compared with the remaining days. Controlling for the effect of topical medications, the cetirizine/cimetidine combination demonstrated a dramatic improvement at 1 and 6 hours, and a moderate improvement at 12 hours after initial medication for the day when compared with the diphenhydramine/placebo combination.

Three liquid formulations with in situ gelling properties have been assessed for their potential for the oral delivery of cimetidine. The formulations were dilute solutions of: (a) enzyme-degraded xyloglucan, which form thermally reversible gels on warming to body temperature; (b) gellan gum and; (c) sodium alginate both containing complexed calcium ions that form gels when these ions are released in the acidic environment of the stomach. The in vitro release of cimetidine from gels of each of the compounds followed root-time kinetics over a period of 6 h. Plasma levels of cimetidine after oral administration to rabbits of each of the formulations were compared with those resulting from administration of a commercial cimetidine/alginate suspension with an identical drug loading. In vivo release characteristics of each of the in situ gelling formulations were similar to those of the commercial preparation.

The effect of cimetidine on the treatment efficacy of praziquantel against Microcotyle sebastis infestation in cultured rockfish Sebastes schlegeli was investigated. Juvenile rockfish were divided into 7 groups, and orally administered praziquantel alone (50, 100 and 200 mg kg(-1) body wt, BW) or in combination with cimetidine at a dose of 200 mg kg(-1) BW for each praziquantel dose. The fish in the control group were administered only saline. The results clearly showed that coadministration of cimetidine with praziquantel led to a significantly increased treatment efficacy of the latter drug, and consequently would lead to a lowering of the total dose of praziquantel, and a reduction in the administration times and costs for the treatment of M. sebastis infestation in cultured rockfish.

Background: There has been a dramatic rise in incidences of Barrett's oesophagus and oesophageal adenocarcinoma. It has been suggested that the introduction and use of acid suppression therapy may be a factor in the rising incidences of Barrett's oesophagus and oesophageal adenocarcinoma., Methods: This was a record linkage study, using a prescribing database and an endoscopy database. Patients who had undergone their first endoscopy during the period 1992-1995 and received the diagnosis of Barrett's oesophagus or oesophagitis were identified. The prescribing of acid suppressants was compared for the 3 years prior to endoscopy, between those with Barrett's oesophagus and those with oesophagitis., Results: There was no significant difference between the Barrett's patients and the oesophagitis patients in the proportion that had been exposed to acid suppression therapy (53.4% vs. 51.7%, P=0.704). The mean number of days of prescribing among those who had been exposed to acid suppression therapy was higher in the Barrett's group (340.5 vs. 237.0 days, P=0.001)., Conclusions: Patients with Barrett's oesophagus have received more acid suppressant therapy prior to diagnosis. The reasons for this are not clear. However, 46.6% of Barrett's patients have not been exposed to acid suppressant therapy.

Objective: To evaluate the efficacy of oral cimetidine as a treatment for painful bladder disease (PBD, variously described as a 'symptom complex' of suprapubic pain, frequency, dysuria and nocturia in the absence of overt urine infection) by assessing symptom relief and histological changes in the bladder wall tissue components, compared with placebo., Patients and Methods: The study comprised 36 patients with PBD enrolled into a double-blind clinical study with two treatment arms, i.e. oral cimetidine or placebo, for a 3-month trial. Patients were asked to complete a symptom questionnaire (maximum score 35), and underwent cystoscopy and bladder biopsy before treatment allocation. On completing treatment the patients were re-evaluated by the questionnaire and biopsy. The symptom scores and bladder mucosal histology were compared before and after treatment, and the results analysed statistically to assess the efficacy of cimetidine., Results: Of the 36 patients recruited, 34 (94%) completed the study. Those receiving cimetidine had a significant improvement in symptoms, with median symptom scores decreasing from 19 to 11 (P < 0.001). Suprapubic pain and nocturia decreased markedly (P = 0.009 and 0.006, respectively). However, histologically the bladder mucosa showed no qualitative change in the glycosaminoglycan layer or basement membrane, or in muscle collagen deposition, in either group. The T cell infiltrate was marginally decreased in the cimetidine group (median 203 before and 193 after) and increased in the placebo group (median 243 and 250, P > 0.3 and > 0.2, respectively). Angiogenesis remained relatively unchanged. The incidence of mast cells and B cells was sporadic in both groups., Conclusions: Oral cimetidine is very effective in relieving symptoms in patients with PBD but there is no apparent histological change in the bladder mucosa after treatment; the mechanism of symptom relief remains to be elucidated.

Gastroesophageal reflux disease (GERD) symptoms are common in pregnancy, occurring in approximately 45% to 80% of pregnant women. Although the symptoms associated with reflux in pregnancy are similar to those described in the nonpregnant state, some of the etiologies are distinct due to hormonal fluctuations and other physiologic changes often associated with pregnancy. Diagnostic tools and therapeutic regimens that might be used without hesitation in the nonpregnant patient must be given with cautious consideration in the gravid patient due to potential fetal risks. Pregnant patients with symptomatic GERD should be managed aggressively with lifestyle modification and dietary changes. Antacids and antacids/alginic acids combination or sucralfate should be considered first-line medical therapy; treatment with cimetidine or ranitidine should be considered; these H2 receptor antagonists are preferred during pregnancy. Proton-pump inhibitors should be used with caution because little human experience is available.

Most xenobiotics are transferred into milk by passive diffusion; however, some drugs have been reported to accumulate in milk as a result of active transport. In the present study, lactating Sprague Dawley rats were used to characterize the transfer of nitrofurantoin into milk. The observed milk to serum concentration ratio (M/S) of 31.1+/-4.0 was 100 times higher than the M/S predicted by diffusion (0.3+/-0.1), indicative of an active transfer into milk. Randomized crossover infusions of nitrofurantoin (0.5mg/h) in the absence and presence of a cimetidine infusion regimen (15mg/h) resulted in the corresponding mean M/S of 29.5+/-5.4 vs. 30.7+/-5.0 and systemic clearance (Cls) of 2.7+/-0.7 vs. 2.2+/-0.4 L/h/kg, respectively. Nitrofurantoin infusions (0.5mg/h) in the absence and presence of a higher cimetidine infusion regimen (30mg/h) resulted in the corresponding mean values for M/S of 23.0+/-7.7 vs. 19.8+/-5.9 and Cls of 2.8+/-0.4 vs. 1.4+/-0.4L/h/kg, respectively. Only the decrease in Cls at the higher cimetidine infusion was statistically significant. These observations provide evidence that nitrofurantoin is actively transported into rat milk by a transporter that is not inhibited by cimetidine. These data suggest the presence of at least two distinct mammary epithelial transporter systems, one that transports organic cations (e.g., cimetidine) and another for anions (e.g., nitrofurantoin).

Aims: To evaluate whether ketoconazole or cimetidine alter the pharmacokinetics of loratadine, or its major metabolite, desloratadine (DCL), or alter the effects of loratadine or DCL on electrocardiographic repolarization in healthy adult volunteers., Methods: Two randomized, evaluator-blind, multiple-dose, three-way crossover drug interaction studies were performed. In each study, subjects received three 10 day treatments in random sequence, separated by a 14 day washout period. The treatments were loratadine alone, cimetidine or ketoconazole alone, or loratadine plus cimetidine or ketoconazole. The primary study endpoint was the difference in mean QTc intervals from baseline to day 10. In addition, plasma concentrations of loratadine, DCL, and ketoconazole or cimetidine were obtained on day 10., Results: Concomitant administration of loratadine and ketoconazole significantly increased the loratadine plasma concentrations (307%; 90% CI 205-428%) and DCL concentrations (73%; 62-85%) compared with administration of loratadine alone. Concomitant administration of loratadine and cimetidine significantly increased the loratadine plasma concentrations (103% increase; 70-142%) but not DCL concentrations (6% increase; 1-11%) compared with administration of loratadine alone. Cimetidine or ketoconazole plasma concentrations were unaffected by coadministration with loratadine. Despite increased concentrations of loratadine and DCL, there were no statistically significant differences for the primary electrocardiographic repolarization parameter (QTc) among any of the treatment groups. No other clinically relevant changes in the safety profile of loratadine were observed as assessed by electrocardiographic parameters (mean (90% CI) QTc changes: loratadine vs loratadine + ketoconazole = 3.6 ms (-2.2, 9.4); loratadine vs loratadine + cimetidine = 3.2 ms (-1.6, 7.9)), clinical laboratory tests, vital signs, and adverse events., Conclusions: Loratadine 10 mg daily was devoid of any effects on electrocardiographic parameters when coadministered for 10 days with therapeutic doses of ketoconazole or cimetidine in healthy volunteers. It is concluded that, although there was a significant pharmacokinetic drug interaction between ketoconazole or cimetidine and loratadine, this effect was not accompanied by a change in the QTc interval in healthy adult volunteers.

In rats, the hypothalamic neurotransmitter histamine participates in regulation of vasopressin secretion and seems to be of physiological importance, because blockade of the histaminergic system reduces dehydration-induced vasopressin secretion. We investigated whether histamine is also involved in regulation of vasopressin secretion during dehydration in humans. We found that 40 h of dehydration gradually increased plasma osmolality by 10 mosmol/kg and induced a fourfold increase in vasopressin levels. Pretreatment with the H(2)-receptor antagonists cimetidine or ranitidine significantly reduced the dehydration-induced increase in vasopressin levels approximately 40% after 34 and 37 h of dehydration, whereas this was not the case with the H(1)-receptor antagonist mepyramine. Dehydration reduced aldosterone secretion by approximately 50%. This effect of dehydration was reduced by both H(1)- and H(2)-receptor blockade after 16 and/or 34 h of dehydration. We conclude that vasopressin secretion in response to dehydration in humans is under the regulatory influence of histamine and that the effect seems to be mediated via H(2)-receptors. In addition, the regulation of aldosterone secretion during dehydration also seems to involve the histaminergic system via H(1) and H(2) receptors.

The low bioavailability of albendazole affects the therapeutic response in patients with echinococcosis. Cimetidine co-administration is reported to improve bioavailability. To analyze the assumed dose-dependent bioavailability of albendazole, we administered 5 to 30 mg/kg albendazole to 6 male volunteers in a randomized cross-over study. To assess the effect of cimetidine (10 mg/kg twice daily), the drug was given with albendazole (20 mg/kg). A dose-dependent bioavailability was not observed. This was due to inter-individual variability of the maximal concentration (Cmax 38%-72%) of albendazole sulphoxide (ABZSX), the active metabolite of albendazole. Cmax was 0.21+/-0.14 mg/L after 5 mg/kg and 0.39+/-0.19 mg/L after 30 mg/kg albendazole (P = 0.217). Cimetidine tended to decrease Cmax by 52% (P = 0.109) and significantly inhibited ABZSX breakdown as indicated by the prolongation of ABZSX elimination half-life from 7.4+/-3.3 hr to 19.0+/-11.7 hr (P = 0.028). Remarkably, the inter-individual variability of Cmax was significantly lower during cimetidine co-administration: 14% versus 72%.

Improgan is an analog of the H(2) antagonist cimetidine that does not act on known histamine receptors, but induces highly effective analgesia in rodents following intracerebroventricular (icv) administration. Since the mechanism of action of this compound remains unknown, improgan analgesia was characterized presently with the tail immersion nociceptive test in mutant mice lacking either the mu (exon 1 of MOR-1), delta (exon 2 of DOR-1) or kappa (exon 3 of KOR-1) opioid receptor. Improgan (30 microg, icv) induced reversible, maximal analgesia in both sexes of all three genotypes (+/+, +/- and -/-) of MOR-1 mutant mice 10 and 20 min after administration, whereas morphine analgesia was reduced (+/-) or abolished (-/-) in these subjects. In DOR-1 mutant mice, improgan was equally effective in all three genotypes, despite the reduction (+/-) or complete loss (-/-) of delta opioid receptor (3H-[D-Pen(2), D-Pen(5)]enkephalin, DPDPE) binding. Similarly, improgan analgesia was equivalent in all three genotypes of KOR-1 mutant mice, whereas kappa-mediated analgesia (U50,488) and kappa opioid (3H-U69,593) binding were abolished in the homozygous (-/-) mice. These studies demonstrate that improgan analgesia does not require intact MOR-1, DOR-1, or KOR-1 genes, and support the hypothesis that improgan-like analgesics act in the CNS by non-opioid mechanisms.

A 55-year-old man with locally advanced rectal carcinoma and liver metastasis was treated with a combination of chemo-radiotherapy (5-FU suppository 100 mg/day and 63 Gy of RT), hepatic arterial infusion chemotherapy (5-FU 1,000 mg/3 h, biweekly), and systemic chemotherapy (5'-DFUR 800 mg/day + cimetidine 800 mg/day). His rectal tumor was reduced and his symptoms such as pain and bleeding had markedly decreased. The river metastasis did not change during the entire course. HAI and administration of 5-FU suppository, 5'-DFUR, and cimetidine were continued. As of 18 months after the onset of the combination therapy, NC has been maintained, and the general condition of the patient is favorable.

Background: The glomerular filtration rate (GFR) can be estimated from plasma creatinine according to the formula of Cockcroft and Gault (CG). When tubular secretion of creatinine is inhibited by cimetidine the mean difference between the Cockcroft-Gault clearance (CG(Cim) and GFR approximates zero, but there is still some interindividual difference, especially in type-2-diabetic patients. We studied during longitudinal follow-up, whether the discrepancies between CG(Cim) and GFR per patient are consistent in time in type-2-diabetic patients., Patients and Methods: In 1996 and 1998 (interval 20-26 months) GFR was measured in 21 patients as the urinary clearance of continuously infused 125I-iothalamate. Plasma creatinine was analyzed with an enzymatic assay before and after oral cimetidine 800 mg t.i.d. during 24 hours. GFR estimations were calculated with the Cockcroft-Gault formula before (CG) and after cimetidine (CG(Cim)) and expressed as means +/- SEM., Results: GFR deteriorated from 89.7 +/- 5.7 to 81.3 + 5.8 ml/min/1.73 m2 and CG(Cim) from 85.3 +/- 5.7 to 81.1 +/- 6.6 ml/min/1.73 m2, whereas CG decreased from 102.4 +/- 6.8 to 98.4 +/- 7.0 ml/min/1.73 m2. Changes in GFR and changes in CG(Cim) were correlated (r = 0.72, p < 0.001) and were not significantly different from each other. The discrepancy between CG(Cim) and GFR per patient in 1996 also correlated with the discrepancy between CG(Cim) and GFR in 1998 (r = 0.85, p < 0.001 )., Conclusions: In individual patients the discrepancies between the CG(Cim) and GFR are consistent in time and the change in GFR is reflected by the change in CG(Cim). This small variability means that CG(Cim), based on an enzymatic plasma creatinine assay, would be suitable for follow-up of GFR in type-2-diabetic patients, independent of albuminuria.

Objective: To examine changes in healthcare utilization resulting from a formulary switch to cimetidine from nizatidine at the Veterans Affairs Pittsburgh Healthcare System., Study Design: A retrospective analysis of administrative and clinical data 6 months before and 6 months after the therapeutic substitution., Methods: The 704 patients who were switched from nizatidine to cimetidine were included in the study. Administrative data included total and primary care clinic visits, emergency room visits, gastrointestinal (GI)-related radiological studies, and GI endoscopic procedures. Discharge summaries were examined, and rates of total and GI-related hospitalizations were calculated., Results: There was no evidence of increased utilization of healthcare resources during the 6 months after the formulary switch. Estimated monthly pharmaceutical savings for the Veterans Affairs Pittsburgh Healthcare System were $7260., Conclusions: A formulary switch from nizatidine to cimetidine can be accomplished at significant pharmaceutical cost savings, and this retrospective study suggests that this can be done without increasing other aspects of healthcare resource utilization.

Purpose: It is believed that most warts are self-limiting and generally require little or no treatment. When numerous or almost complete infestation of the perineum, genital area and groin is encountered it can be distressing and a difficult problem to treat in children. Multiple treatments with caustic agents are sometimes necessary, and treatment of perigenital warts may require use of anesthesia for multiple procedures. Cimetidine is a histamine receptor antagonist that has been used mainly to treat peptic ulcer disease. Recently it has been reported to be useful for the treatment of mucocutaneous candidiasis, herpes simplex, herpes zoster and verruca because of its immunomodulatory effects. Several studies have been published indicating its effectiveness in the treatment of warts., Materials and Methods: We treated 4 children with extensive condylomata acuminata of the genital and perigenital areas with high doses of cimetidine in an attempt to eradicate the condyloma and avoid recurrence in 2 and as primary treatment in 2. All patients were treated with 30 to 40 mg./kg. cimetidine daily in 3 divided doses during a 3-month period., Results: All patients are free of condyloma at 24 months following treatment., Conclusions: Our results show that cimetidine is useful for primary and adjunctive treatment of condyloma in young children. It also appears to be effective as first line therapy.

Objective: The objective of this study was to examine the pharmacokinetics and the tolerability/safety of mirtazapine and cimetidine separately and in combination following oral administration of multiple doses., Methods: This was a double-blind, placebo-controlled, two-period cross-over, multiple-dose pharmacokinetic interaction study in 12 healthy male subjects. They received either cimetidine (800 mg b.i.d.) or placebo in combination with (commercially available, racemic) mirtazapine (30 mg nocte). Cimetidine and placebo were administered for 14 days, with mirtazapine added during days 6-12 of each period. Serial blood samples for kinetic profiling were taken on day 5 and day 12 for cimetidine and on days 12-14 for mirtazapine., Results: The co-administration of cimetidine resulted in a statistically significant increase in the area under the curve (AUC(0-24)) and Cmax of mirtazapine (54% and 22% respectively). The AUC(0-24) of demethylmirtazapine increased only slightly, and there was no effect on Cmax. The elimination half-lives for both mirtazapine and its demethyl metabolite were unaffected by cimetidine co-administration. The trough and average plasma concentrations during the steady state were elevated during cimetidine treatment (62% and 54%, respectively). Mirtazapine had no effect on the pharmacokinetics of cimetidine., Conclusion: Co-administration of cimetidine (800 mg b.i.d.) and mirtazapine (30 mg nocte) resulted in increased steady-state plasma levels of mirtazapine (C(ss,min) = +61%, P < 0.05; C(ss,av) = +54%, P < 0.05), probably as a result of increased bio-availability. The Cmax (+22%, P < 0.05) and AUC(0-24) (+54%, P < 0.05) also increased. Due to the variability of the mirtazapine plasma levels in patients, the clinical meaning of these increases is probably limited. Co-administration of mirtazapine did not alter cimetidine pharmacokinetics.

Introduction: The aim of the study was to investigate the long term effect of diet, exercise and intermittent treatment of cimetidine on body weight and maintenance of weight lost during treatment., Material and Methods: Fifty women and five men who had completed a 8 week randomized double-blind, placebo-controlled trial of cimetidine for weight loss were invited to participate in an open, non-randomized follow-up study of 42 months. The study was designed to compare weight loss and/or weight gain in subjects who, dependent on their level of motivation, volunteered to participate in an intervention or non-intervention group. In the intervention group the subjects were treated with cimetidine for 8 weeks twice a year, followed a diet restriction and performed regular exercise. In the non-intervention group the subjects had no behavioral treatment. Twenty two subjects volunteered to participate in the intervention program whereas 33 subjects volunteered to participate in the non-intervention group., Results: In the intervention group, non-significant reductions in body weight (1.9 +/- 5.5 kg), BMI (0.6 +/- 1.7 kg/m2), body fat% (1.7 +/- 2.9) and waist circumference (2.1 +/- 5.9 cm) were found. In the non-intervention group there was a significant increase in body weight (7.5 +/- 5.3 kg), BMI (2.6 +/- 1.8 kg/m2), body fat% (3.0 +/- 3.3) and waist circumference (6.7 +/- 5.1 cm). Among the group of subjects initially treated with cimetidine for 8 weeks and who followed a subsequent intervention of additional 42 months (n = 16), there was a 15.1% weight loss. Among the group initially treated with placebo for 8 weeks and who volunteered to participate in the non-intervention group (n = 22), there was a weight gain of 8.6%. In conclusion, the combination of diet restriction, regular exercise and intermittent treatment of cimetidine appears to have long term effects on body weight and maintenance of weight loss.

Adenocarcinoma of the lower oesophagus and the gastric cardia has shown a dramatic worldwide increase in incidence over the last 25 years, but the cause is unknown. A large number of drugs have been introduced over this period of time, and it has been suggested that drugs that relax the lower oesophageal sphincter (DRLOS) might be causative, and on the other hand that non-steroidal anti-inflammatory drugs (NSAIDS) may be protective. H2-receptor antagonists (H2RAs) may allow achlorhydric reflux to continue without symptoms, and it is postulated that such asymptomatic reflux is uncontrolled by the usual conservative measures and may lead to increased oesophageal damage. H2RAs were first marketed in 1970 and might be the cause of the observed increase of cardio-oesophageal adenocarcinoma (COA). In a case-control study, the records of 56 subjects who died of COA in the period 1 January 1990 to 31 December 1992 were compared with those of 56 age-/sex-matched controls who died of myocardial infarction. They were 28 females and 84 males, mean age 69.8 years. The NHS records containing the lifetime prescription history of each subject were retrieved from the health authority. Each prescription was recorded, omitting drugs taken in the two years before diagnosis. Analysis was performed using conditional logistic regression. Other variables, including the use of antacids, steroids, smoking and alcohol, were also examined. Subjects dying of COA were more likely to have consumed H2RAs (relative risk (RR) 7.50, 95% CI 1.33-42.09, P < 0.02). On the other hand, they were less likely to have consumed NSAIDs (RR 0.16, 95% CI 0.03-0.93, P < 0.04) or DRLOS (RR 0.14, 95% CI 0.02-1.0, P = 0.05). This study supports a protective effect from NSAIDs against COA, but the similar effect of DRLOS is related to the increased use of cardiac drugs in the control group. H2RAs appear to have a harmful effect, which may be related to the worldwide increase in COA. However, the trend may have been apparent before cimetidine was widely available, and it is possible that the cause is multi-factorial.

We have found that the binary system, consisting of a precipitate of cimetidine and naproxen, became amorphous due to intermolecular interaction. In order to clarify the interaction between cimetidine and other drugs, the physicochemical properties of binary systems consisting of cimetidine and drugs, phenacetin, salicylamide or indomethacin, were investigated. X-ray powder diffraction patterns and thermal analysis findings for the precipitates indicated that the cimetidine-indomethacin system has an amorphous structure, whereas the cimetidine-phenacetin and cimetidine-salicylamide systems do not. Fourier-transform infra-red (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy findings suggested that there is an intermolecular interaction between a proton in the imidazole ring of cimetidine and the C=O in the COOH of indomethacin. Since an interaction by the hydrogen bond between cimetidine and indomethacin would prevent three-dimensional arrangements of the molecules, the precipitate would be amorphous. In the cimetidine-indomethacin system, decarboxylation of indomethacin occurred below the melting temperature, indicating that the chemical stability decreased upon precipitation. Cimetidine was found to interact with drugs with a carboxyl group. The interaction would be applicable to make the amorphous system of the drugs and increase the solubility of the drugs.

Oral cimetidine for the treatment of verruca continues to be a topic of discussion and controversy. Although its usage has gained popularity because it offers an alternative to conventional topical and surgical verruca therapy, its reported efficacy in managing warts lacks consistency in outcomes. Using high doses of oral cimetidine, therefore, raises concern about possible untoward effects. Cimetidine relies on effecting a change in the immune system to eradicate the verruca, but such a change in the immune system may cause patients to develop responses detrimental to their well being. The authors present an unusual case of severe delayed hypersensitivity with the use of oral cimetidine.

A phase II study was performed to evaluate the efficacy of cisplatin combined with interleukin-2 and interferon-alpha2b administered subcutaneously to patients with metastatic malignant melanoma (MMM). Between April 1994 and January 1999, 87 patients with MMM and a WHO performance status of < or = 2 were entered into the study. The first 42 patients had prophylactic cimetidine; the other 45 patients did not. An overall response rate of 27% was achieved in the 82 patients evaluable for response. The median response duration was 7.0 months (range 4.4-29.0 months). The median survival for all patients was 10.1 months (range 0.4-64.9+ months). Toxicity was substantial but generally manageable and usually reversed on dose reduction or temporary interruption of treatment. Two patients (2%) died of treatment-related toxicity. No difference in response or survival was seen in the patients treated with or without cimetidine. In multivariate analysis, lactate dehydrogenase level (P < 0.001), number of metastatic sites (P = 0.014) and performance status (P = 0.035) was shown to be independent prognostic factors for survival. This high dose interleukin-2 subcutaneous regimen resulted in a small fraction of long-term survivors. The response and survival results were not superior to other studies using lower and less toxic interleukin-2 doses.

The purpose of this study was to determine the characteristics of intestinal absorption and metabolism of cimetidine. The initial finding of the appearance of cimetidine sulfoxide in rat and human jejunum from cimetidine perfusions had prompted an isolation of mucosal membrane transport and enterocyte metabolism contributions in earlier membrane vesicle and microsomal studies, respectively. In this report, perfusion studies in rat small intestine detail regional differences in intestinal elimination. Cimetidine S-oxide appears to a significantly greater extent in the jejunum compared with the ileum. Jejunal metabolite appearance is shown to be a function of the pH-dependent intracellular uptake of cimetidine. Cimetidine permeability decreases with increasing perfusion concentration in both jejunum and ileum. Similar permeability magnitudes and concentration dependence are observed in both regions. Perfusion studies with inhibitors of cimetidine mucosal transport and inhibitors of microsomal S-oxidation provide an inhibition profile suggesting that jejunal cimetidine permeability decreases with increasing intracellular cimetidine concentration. The data support a reduction in paracellular cimetidine absorption as controlled by intracellular cimetidine. This inference is drawn on the basis of mass balance. Because significant appearance of cimetidine S-oxide was previously found in human jejunal perfusions, this region-dependent intestinal elimination process detailed in rats may be relevant to drug plasma-level double peaks observed in clinical studies. Saturation of jejunal metabolism at typical oral doses may limit paracellular absorption of cimetidine in the jejunum and contribute to the double peak phenomenon and to absorption variability.

The effects on gastric pH of a single administration of 200 mg cimetidine (Tagamet HB) were compared to multiple doses of a liquid antacid (Mylanta) using a pH microelectrode. Gastric pH was monitored for 8 hr in 20 normal fasting volunteers in a crossover design to compare Tagamet HB (two 100-mg tablets administered as a single dose) with Mylanta Suspension, an initial 17.5-ml dose of antacid with additional doses given when gastric pH fell below 3.5. Both treatments increased the pH above 3.5 during the first hour following treatment, with Mylanta being more effective than Tagamet HB. Interestingly, to sustain the reduction in acidity during this 1-hr interval, a mean of 2.45 doses of antacid were administered. Although multiple doses of Mylanta kept the pH above 3.5 (for at least 25% of the time) for the first 4 hr, the single administration of 200 mg of Tagamet HB maintained gastric pH above 3.5 (greater than 25% of time) for the full 8 hr of the study. Compared to Mylanta, the percent of time gastric pH was >3.5 was significantly higher with Tagamet HB during the 3rd to 8th hour after dosing. This study demonstrates that 200 mg of cimetidine administered as Tagamet HB is significantly more effective and has a much longer duration of action in raising gastric pH >3.5 than six doses of Mylanta.

Non-crosslinked and crosslinked chitosan microspheres were prepared by a spray drying method. The microspheres so prepared had a good sphericity and a smooth but distorted surface morphology. They were positively charged. The particle size ranged from 2 to 10 micron. The size and seta potential of the particles were influenced by the crosslinking level. With decreasing amount of crosslinking agent (either glutaraldehyde or formaldehyde), both particle size and zeta potential were increased. Preparation conditions also had some influence on the particle size. DSC studies revealed that the H2 antagonist drug cimetidine, as well as famotidine was molecularly dispersed inside the microspheres, in the form of a solid solution. The release of model drugs (cimetidine, famotidine and nizatidine) from these microspheres was fast, and accompanied by a burst effect.

Activation of histaminergic and noradrenergic/adrenergic neurons in the brain stimulates the release of the neurohypophysial hormones arginine vasopressin (AVP) and oxytocin (OT) and are involved the mediation of the hormone responses to physiological stimuli such as dehydration and suckling. We therefore investigated whether the two neuronal systems interact in their regulation of AVP and OT secretion in conscious male rats. When administered intracerebroventricularly (i.c.v.), histamine (HA) as well as the H1 receptor agonist 2-thiazolylethylamine or the H2 receptor agonist 4-methylHA stimulated AVP and OT secretion. Prior i.c.v. infusion of antagonists specific to alpha or beta adrenergic receptors or their subtypes did not significantly affect the hormone response to HA or the histaminergic agonists. Infused i.c.v. norepinephrine (NE) or epinephrine (E) increased AVP and OT secretion. Prior i.c.v. infusion of the H1 receptor antagonist mepyramine or the H2 receptor antagonist cimetidine significantly inhibited the AVP and OT responses to NE and the AVP response to E, whereas only cimetidine inhibited the OT response to E significantly. Systemic pretreatment with imetit, which by activation of presynaptic H3 receptors inhibits neuronal synthesis and release of HA, decreased the AVP and OT responses to NE and E significantly. In the doses used, HA and E had no significant effect on mean arterial blood pressure. NE increased mean arterial blood pressure 10% at 1 and 2.5 min, whereafter the blood pressure returned to basal level within 10 min. The results indicate that noradrenergic and adrenergic neurons stimulate AVP and OT secretion via an involvement of histaminergic neurons, which may occur at magnocellular neurons in the supraoptic and paraventricular nuclei of the hypothalamus. The stimulatory effect of the amines on neurohypophysial hormone secretion seems to be independent of a central action on blood pressure. In contrast, a functionally intact noradrenergic and adrenergic neuronal system seems not to be a prerequisite for a HA-induced release of AVP and OT. The present findings further substantiate the role of histaminergic neurons in the central regulation of neurohypophysial hormone secretion.

Various immunomodulating agents have been used in the treatment of recalcitrant warts, but none is uniformly effective. Drugs like cimetidine and levamisole have been tried with varying success rates. Given the different target activities of immunomodulation by levamisole and cimetidine, we questioned whether the combination might be more effective and conducted this double-blind comparative trial of a combination of cimetidine and levamisole versus cimetidine alone. Forty-eight patients with multiple recalcitrant warts were assigned to two treatment groups (A and B) in double-blind fashion. Of the 48 patients, 22 in group A and 21 in group B were able to be evaluated. At the end of therapy, cure rates obtained were 45.5% (10/21) in cimetidine treated patients (group A) and 85.7% (18/21) in combination treated patients (group B). A statistically significant improvement was seen in patients treated with the combination of levamisole and cimetidine (P < 0.01). A similar statistically significant result was obtained on using intention to treat analysis (P < 0.02). The rate of regression was faster in group B (average regression period of 7 weeks compared with 10 weeks in group A). The present study demonstrated that the combination of cimetidine with levamisole is more effective than cimetidine alone and is a highly effective therapy for the treatment of recalcitrant warts.

The influence of cimetidine (400 mg) on the salivary pharmacokinetics of oral paracetamol (1 g) was studied in 8 healthy subjects under two protocols--concomitant and delayed administration of cimetidine. There were no significant changes in the salivary pharmacokinetics of paracetamol when the two drugs were concomitantly administered (P > 0.100). Delayed administration of paracetamol 1 h after cimetidine, on the other hand, was associated with significant changes as compared to control. The peak salivary concentration (Cmax) and absorption rate constant (Kab) were significantly reduced (P < 0.05), while the time to peak concentration (Tmax), absorption half-life constant (t1/2ab) and lag time were all significantly increased (P < 0.05). Elimination half-life (t1/2el) was also significantly increased (P < 0.05). These findings indicated that cimetidine does not affect the pharmacokinetics of paracetamol when the two drugs were concomitantly administered but impaired the absorption of paracetamol when the administration of the latter was delayed by 1 h after cimetidine. The therapeutic implication of this interaction is that the efficacy of paracetamol may be affected.

Thirty-eight colorectal cancer patients were randomly assigned to treatment group, which took cimetidine in the perioperative period, and control group to which no drug was given. Twenty healthy volunteers served as normal controls. NK cells were measured by immunocytochemical technique. The results showed that NK percentages before treatment in both groups of patients were significantly lower than those in normal controls (P < 0.05). NK cell percentages at admission, before operation, on the 2nd and the 10th postoperative days were 14.84 +/- 4.41, 15.74 +/- 3.75, 17.21 +/- 3.69, 21.05 +/- 4.54, respectively, for the treatment group, and 15.00 +/- 2.77, 13.05 +/- 2.46, 14.21 +/- 2.19, 15.58 +/- 1.68, respectively, for control group. The difference was statistically significant (P < 0.01), suggesting that the perioperative administration of cimetidine could help restore NK cells in colorectal cancer patients.

Background: Because of their tolerance and safety, low doses of H2-receptor antagonists are now increasingly used in some countries for self-care medication of gastro-oesophageal reflux symptoms., Aim: The purpose of this randomized, double-blind, placebo-controlled, five-way crossover study was to determine and to compare the effects of low doses of ranitidine and cimetidine both on gastric pH and on oesophageal acid exposure., Methods: Gastric and oesophageal pH were simultaneously monitored in 20 healthy subjects using two glass pH electrodes, after placebo and single doses of ranitidine 75 mg and cimetidine 200 mg (effervescent and tablet forms), for 4 h before and after a meal., Results: During the fasting period, median gastric pH rose significantly with both drugs, but more rapidly with the effervescent forms; the oesophageal acid exposure was significantly decreased by all drug regimens. After the meal, although there was no significant difference in gastric pH values, oesophageal acid exposure was significantly decreased in comparison with placebo with both forms of ranitidine (P < 0.05), and also for ranitidine tablets in comparison with cimetidine tablets (P < 0.05)., Conclusions: Low doses of ranitidine and cimetidine increase gastric pH, with a more pronounced effect for ranitidine. Effervescent formulations of both drugs induce a slightly more rapid initial increase in pH than tablets. Ranitidine demonstrates a more prolonged effect than cimetidine and decreases oesophageal acid exposure monitored after a meal ingested 4 h after the drug intake.