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Overnight gastric secretion was studied in 32 patients with acute duodenal ulcers before treatment and whilst taking cimetidine 400 mg b.d. After 6 weeks of treatment with cimetidine 400 mg b.d. 13 patients had healed ulcers, seven patients had healed ulcers but a persistent erosive duodenitis, and 12 patients had persisting ulceration. Inhibition of nocturnal gastric secretion by cimetidine 400 mg b.d. was most profound in patients who healed their ulcers completely; a less profound inhibition of nocturnal gastric secretion was seen in the non-healing and duodenitis groups. In patients with persisting ulcers and poor inhibition of nocturnal gastric secretion by cimetidine, gastric secretion could be suppressed by either cimetidine 400 mg b.d. in combination with pirenzepine 50 mg b.d., or by cimetidine 1600 mg nocte, but suppression of nocturnal gastric secretion was more effective with cimetidine 1600 mg than cimetidine with pirenzepine.

In a double-blind, randomised trial two drug regimens were compared in a group of 129 patients with uncomplicated duodenal ulcers, 64 receiving cimetidine (800 mg) and pirenzepine (50 mg) at bed-time, 65 receiving cimetidine (800 mg) and a placebo at bed-time. Neither statistically nor clinically was there an important difference in effectiveness and tolerance between the two drug regimens.

Increased GH levels in Type I diabetes mellitus have been implicated in the pathogenesis of metabolic complications such as the so-called dawn phenomenon. GH secretion is under control of cholinergic mechanisms. In 21 Type I diabetic patients the effect of oral administration of the anticholinergic drug pirenzepine in addition to intensive insulin therapy on GH and blood glucose levels was studied. At 21.30, 08.00 and 12.00 h, all patients received in random order 50 mg of pirenzepine or placebo po. Blood for determination of GH, blood glucose, cortisol and C-peptide levels were obtained at 3-h intervals. Serum levels of plasma glucose and GH were significantly lower under pirenzepine than under placebo (P less than 0.05 and P less than 0.01, respectively). Serum levels of cortisol, free insulin and C-peptide were comparable on the test and the control day. Our data indicate that in Type I diabetes mellitus the anticholinergic drug pirenzepine is effective in decreasing both GH and blood glucose levels.

Forty-three patients with duodenal ulcer were treated with almagel and gastrocepin, had four meals a day. Twenty-one patients received the drugs according to the standard schedule before meals. The test group of 22 patients took meals and drugs in turn during 24 hours with the aim of a continuous moderate reduction of acidity and activity of proteolytic enzymes. Statistical analysis of the results showed a shorter duration of the ulcer healing in the test group. This conclusion permits recommending the above novel modification of the standard treatment for use in duodenal ulcer treatment as advantageous.

A dialysis loop cannula was implanted into rat striatum under anesthetized condition, and the area was perfused with Ringer's solution under freely moving condition after 3 days for surgical recovery. Dopamine (DA) and 3,4-dihydroxyphenylacetic acid recovered in the dialysate were measured by high-performance liquid chromatography with electrochemical detection. The effects of M1- and M2-muscarinic receptor agents, which were perfused continuously into the striatum through the dialysis membrane, were investigated. Continuous perfusion of AF102B, an M1-selective agonist, and oxotremorine, a non-selective agonist, resulted in a dose-dependent increase in the striatal DA release. Pirenzepine (10(-5) and 10(-7) M), an M1-selective antagonist, decreased the release of DA, and the stimulatory effect of AF102B (10(-5) M) was completely inhibited by 10(-5) and 10(-7) M pirenzepine, while the stimulatory effect of oxotremorine (10(-4) M) was only partly inhibited by 10(-5) M pirenzepine. AF-DX116 (10(-5) M), an M2-selective antagonist, increased the DA release, and showed an additive effect on the DA release evoked by AF102B (10(-5) M), whereas it produced no significant effect on oxotremorine (10(-5) M)-evoked DA release. These results suggest that in vivo DA release in the rat striatum is modulated by different subtypes of muscarinic receptors; i.e., the stimulatory effect is mainly mediated by M1-sites and inhibitory effect is mainly mediated by M2-sites. The changes in the DA release induced by the various drugs were prevented by pretreatment with tetrodotoxin (TTX). Since action potential-dependent DA release (exocytosis) is blocked by the pretreatment with TTX, those drugs affect DA release by means of action potential-dependent processes.

Atropine-induced bradycardia is traditionally ascribed to central vagal stimulation, although bradycardia has also been observed after administration of quarternary amines. Pirezepine, a selective M1-antagonist, causes bradycardia in therapeutic doses for which a peripheral mechanism is postulated. This hypothesis has been investigated in healthy volunteers. Atropine 0.5 mg caused significant bradycardia from 210 min and pirenzepine 10 mg after 60 min. After prior beta-blockade, the bradycardic action of the anti-cholinergic drugs was more marked. Pirenzepine-induced bradycardia was reversed by higher doses of atropine. It is suggested that atropine- and pirenzepine-induced bradycardia results from M1-blockade of sympathetic ganglia. In addition, low concentrations of atropine and therapeutic doses of pirenzepine may cause an increase in acetylcholine, perhaps due to a presynaptic effect on nerve endings.

Pirenzepine, the prototype M1 muscarinic receptor antagonist, is an important compound for investigating the functional significance of M1 receptors at the integrated level of behavior but may have limitations imposed by its physical chemistry. Like the nonselective antagonist methylatropine, pirenzepine is highly hydrophilic and crosses the blood-brain-barrier with difficulty. We compared methylatropine with pirenzepine, given intraperitonealy, as antagonists of the behavioral effects of peripheral or central muscarinic activation. Lever-press responses of male Sprague-Dawley rats were maintained under a schedule requiring 10 responses for each food delivery. Administration of oxotremorine or the quaternary analog oxotremorine-M decreased rates of responding by at least 90%. Both methylatropine and pirenzepine antagonized the behavioral effects of oxotremorine-M; maximum reversal was 70%. Although methylatropine was about 30 times more potent than pirenzepine as an antagonist of the peripheral muscarinic activity of oxotremorine-M, it was inactive as an antagonist of oxotremorine when given in doses up to 153 mumol/kg. Pirenzepine, however, reversed oxotremorine-induced behavioral effects, with a maximum antagonism of 50%. These results suggest that pirenzepine interacts with central muscarinic receptors when administered systemically without producing marked behavioral effects of its own. Systemically administered pirenzepine may thus be a useful tool in further investigations of the relevance of M1 receptors to behavioral function.

One hundred consecutive patients with non-ulcer dyspepsia (NUD) and the endoscopic diagnosis of erosive prepyloric changes (EPC) were included in a 4-week double-blind, placebo-controlled trial. The patients were randomly allocated to treatment with either Al-Mg antacids (one tablet four times daily; acid-neutralizing capacity, 120 mmol/day) or antacid placebo, in combination with either pirenzepine (50 mg twice daily) or pirenzepine placebo. Ninety patients completed the study. Symptoms improved during the 4 weeks in all treatment groups, irrespective of the treatment given. Neither pirenzepine nor antacid was significantly superior to placebo. Re-endoscopy after 4 weeks of treatment showed no significant change in the EPC grade. No serious side effects were observed, but xerostomia occurred more frequently in patients treated with pirenzepine than in those treated with placebo (p less than 0.01).

In order to investigate the behavioural effect of selective blockade of M1 muscarinic receptors in the forebrain, and to characterize a new model for the evaluation of muscarinic agonistic activity, the effect of intrastriatally injected pirenzepine was studied in mice. The direct injection of pirenzepine (0.01-1 microgram/mouse) into the right striatum of conscious mice resulted in contralateral turning behaviour. When injected intraperitoneally (IP) 15 min before pirenzepine (1 microgram), the muscarinic receptor agonists arecoline and pilocarpine (0.3-3 mg/kg), oxotremorine (0.003-0.03 mg/kg) and RS 86 (0.03-1 mg/kg) antagonized pirenzepine-induced turning, as did the choline-esterase inhibitor physostigmine (0.01-0.1 mg/kg) and the nootropic drug aniracetam (10-30 mg/kg). Haloperidol (0.03-0.3 mg/kg IP) weakly, but significantly, decreased the effect of pirenzepine, whereas (+/-) sulpiride (3-100 mg/kg) failed to affect it. Finally, (+/-)-amphetamine (0.1-3 mg/kg IP), citalopram (1-30 mg/kg IP) and muscimol (0.03-0.3 mg/kg IP) failed to modify pirenzepine-induced turning when administered prior to intrastriatal pirenzepine. These results suggest an involvement of M1 muscarinic receptors in rotational behaviour, and indicate that pirenzepine-induced turning may represent a new model for studying the central activity of cholinomimetic drugs.

The effects of cholinomimetics and muscarinic antagonists were compared following topical administration to the eyes of anaesthetized rats. For tests with cholinomimetics, clonidine (0.3 mg/kg) was used to induce mydriasis via central inhibition of parasympathetic tone. Full, dose-dependent miosis was induced by acetylcholinesterase inhibitors [physostigmine greater than neostigmine greater than tetrahydroaminoacridine (THA)] and by membrane channel blockers (4-aminopyridine greater than 3,4-diaminopyridine). Oxotremorine was the most potent direct agonist tested [oxotremorine greater than arecaidine propargylester (APE) greater than arecoline greater than carbachol greater than ethoxyethyltrimethyl-ammonium iodide (EOE) greater than RS 86]. Some putative M1 selective agonists were weakly active or behaved as partial agonists (pilocarpine greater than AH6405 greater than Mc-A-343 greater than isoarecoline). Of the antagonists, compared in non-clonidine treated rats, scopolamine hydrochloride was the most potent. Of the receptor selective antagonists the M2 (ileal) selective compounds hexahydrosiladifenidol and 4-DAMP were more potent than either M1 selective (pirenzepine, telenzepine) or M2 (atrial) selective (AF DX 116) drugs. These data tentatively suggest the involvement of an M2 (ileal) type muscarinic receptor. Potency was lower for quaternary structures, probably due to impaired corneal penetration. The potency of pirenzepine and telenzepine was increased 60-fold at low pH following topical administration. Acid induced corneal damage does not appear to account for this potency shift as the effects of scopolamine and several agonists (oxotremorine, pilocarpine and McNA-343) were not substantially altered by acid media. For pirenzepine the potency shift appears to be related to protonation of the second amino group (N1) in the piperazine tail (pKa = 2.05).(ABSTRACT TRUNCATED AT 250 WORDS)

During a controlled, randomized, double blind study, 30 patients of a neurosurgical intensive care unit were treated with ranitidin and placebo (group 1) or ranitidin and pirenzepin (group 2). No significant difference in the effectivity of both methods was established, presumably due to the small number of cases. The pH values of group 2 lay in the median above 3.5, whereby the difference only became statistically significant after a seven-day period of therapy. In how far the increase of the pH value represents the only factor of a stress ulcer prophylaxis requires further investigation, particularly in connection with pulmonary risks caused by this.

Three different doses of the M1-selective antimuscarinic compound telenzepine were investigated in the treatment of acute duodenal ulcer in a randomized, double-blind dose-range finding study. In four investigating centers, 120 patients with endoscopically proven, florid duodenal ulcer were treated with either 1.5 mg, 3 mg or 5 mg telenzepine once daily at bedtime (40 patients per dose group). After two weeks of treatment differences in the healing rates were statistically not significant. After four weeks the ulcers of 26 (65%) patients in the 1.5 mg group and 34 (85%) and 31 (78%) in the 3 mg and 5 mg groups, respectively, were completely healed. Only the difference in the healing rates between the 1.5 and 3 mg groups was significant at p less than 0.05. Mean reductions in ulcer area were 90% (1.5 mg), 97% (3 mg) and 93% (5 mg) after four weeks; 1.5 vs. 3 mg, p less than 0.025. These results show that telenzepine dose-dependently accelerates ulcer healing and that maximal effect is obtained with the 3-mg dose. The ulcer symptoms were dose-dependently alleviated. Dry mouth of moderate or severe intensity was stated more frequently under 5 mg telenzepine (by 14% of patients) than under 1.5 and 3 mg (5% each). The antimuscarinic side effect "disturbed accommodation" was rarely found. It is concluded that once daily administration of 3 mg in the evening must be regarded as the optimal dosage regimen of telenzepine.

In rats, mixed M1/M2 muscarinic ligands induce a discrimination which is of central origin and selectively mediated by either one or both muscarinic receptor subtypes. In the present study we examined the effects of intracerebroventricular (i.c.v.) pirenzepine, a relatively selective M1 receptor antagonist which does not cross the blood-brain barrier, on muscarinic discriminations. Groups of six rats were trained to discriminate, in a two-lever operant task, either 0.062 mg/kg subcutaneous (s.c.) scopolamine or 0.075 mg/kg s.c. oxotremorine. When the rats had been well trained in the procedure, the discriminative effects of various i.c.v. muscarinic ligands were examined. Scopolamine (1.5-12 micrograms i.c.v.), but not pirenzepine (20-40 micrograms i.c.v.), generalized to s.c. scopolamine. Oxotremorine (0.75-6 micrograms i.c.v.) generalized to s.c. oxotremorine. Scopolamine (12 micrograms i.c.v.), but not pirenzepine (20-40 micrograms i.c.v.), antagonized the oxotremorine cue. These results suggest that activation of the M1 receptor is not the prominent component of muscarinic stimulus control.

Eighty-four patients with healed duodenal ulcers were treated for 1 year with pirenzepine, 50 mg twice daily, or placebo in this double-blind, randomized, multicenter trial. Clinical follow-up and endoscopy were performed before and after 3, 6, and 12 months of treatment. Endoscopy was also carried out whenever symptoms compatible with ulcer recurrence were present for more than 2 days. Both groups were well matched for age, sex, duration of peptic ulcer disease, and smoking habits. There were 21 drop-outs due to lack of compliance. Therefore, 32 patients treated with pirenzepine and 31 with placebo were included in the analysis. Expressed in cumulative percentage of recurrence, with pirenzepine, 28% of the patients had a relapse at 3 months, 41% at 6 months, and 53% at 12 months; with placebo, the recurrence rates were 58% at 3 months, 68% at 6 months, and 71% at 12 months. The mean success time at 1 year is also longer for pirenzepine (7.38 months) than for placebo (5.52 months). These differences are significantly in favor of pirenzepine (p less than 0.05). Both treatments were well tolerated. Dry mouth was more frequently observed with pirenzepine (14 versus 5 patients). We conclude that pirenzepine, 50 mg twice daily, significantly reduces the relapse rate of duodenal ulcers during a 1-year maintenance treatment.

The inhibitory action of pirenzepine on acid secretion of isolated guinea pig parietal cells was investigated by the aminopyrine method. Pirenzepine markedly inhibited acid secretion of isolated parietal cells induced by carbachol in a dose-dependent manner but showed no inhibition on acid secretion stimulated by histamine. These results may suggest a direct action of pirenzepine on muscarinic receptors in parietal cells.

1. The pharmacokinetics of pirenzepine (Gastrozepin) was studied after single and multiple oral administration in gastric ulcer and duodenal ulcer patients. 2. With a dose of 50 mg of pirenzepine, plasma levels reached a maximum 2 h after the administration in both groups (gastric ulcer patients: 57.2 +/- 31.8 ng/ml, duodenal ulcer patients: 48.0 +/- 18.0 ng/ml), and decreased bi-phasically with an elimination half-life (t1/2 beta) of 13.9 +/- 4.0 and 17.9 +/- 4.5 h, respectively. The area under the plasma level curve were 844 +/- 319 ng X h/ml and 663 +/- 151 ng X h/ml in the respective group. 3. The plasma levels of pirenzepine after multiple administration (50 mg was given as a loading dose, and thereafter 25 mg was given as a maintenance dose at an interval of 12 h for 7 days) maintained certain steady state levels from just after the start of administration. 4. It can be concluded that there is no significant difference in the pharmacokinetics of pirenzepine between gastric and duodenal ulcer patients. It can be judged that twice-daily administration of pirenzepine is enough for ulcer treatment.

A multicenter, double-blind, randomized controlled study was conducted in 314 duodenal ulcer patients to compare the efficacy and safety of the antimuscarinics telenzepine and pirenzepine in the treatment of duodenal ulcer. Patients received telenzepine 3 mg (156) once-daily at bedtime or 50 mg pirenzepine (158) two times daily for 2 weeks. If ulcerous lesions persisted treatment was extended to 4 weeks. Efficacy was assessed by relief of ulcer pain and endoscopic findings of ulcer healing. Safety was determined on the basis of side effects and results of laboratory tests. The 2- and 4-week healing rates achieved with telenzepine were 21.1 and 67.3%, respectively, and with pirenzepine they were 20.0 an 69.0%, respectively; the differences in healing rates for the two drugs were not statistically significant. Similarly both drugs provided satisfactory relief of pain. The incidence of untoward effects was 24.5% with telenzepine and 29.7% with pirenzepine, dryness of mouth being most prominent (20.4 vs. 19.3%). With telenzepine blurred vision was reported in a significantly lower rate compared to pirenzepine (0.7 vs. 4.2%, p less than 0.05). Clinically relevant abnormal laboratory tests were not observed. The present study shows for the first time that the newly developed antimuscarinic drug telenzepine is in a single nocturnal dosage regimen (3 mg nocte) as effective as pirenzepine (50 mg bid) in the treatment of duodenal ulcer.

Sixty-nine patients with symptomatic and endoscopically diagnosed gastric or duodenal ulcers received treatment with either pirenzepine 100 mg or cimetidine 800 mg one hour before bedtime in a prospective randomised, double blind study. Fifty-five patients completed the six weeks treatment period of whom 13/15 (87%) gastric ulcers and 13/16 (81%) duodenal ulcers, healed with pirenzepine compared to 8/11 (73%) gastric ulcers and 10/13 (77%) duodenal ulcers treated with cimetidine for the same period. The differences in healing rates between pirenzepine and cimetidine were not statistically significant. Pirenzepine 100 mg administered at night is therefore an effective treatment for gastric and duodenal ulcers.

The authors investigated the therapeutic results in gastroduodenal ulcers in 96 patients treated with Gastrozepin (Slovakofarma), using daily doses of 75 mg combined with antacids. The examinations were made by means of a videogastroscope of Welch-Allyn Co. with subsequent control after four weeks, and if the ulcer was not healed, after two-week intervals. During the first examination they recorded the size of the ulcer and during check-up examinations the stage of healing. In a group of 51 men with a mean age of 44.4 years the incidence of duodenal ulcers was 29 cases (59.6%) and gastric ulcers 22 cases (43.1%). In a group of 45 women with a mean age of 51.4 years duodenal ulcers were detected in 24 (53.3%) and gastric ulcers in 21 (46.7%). After one-month treatment of 53 duodenal ulcers 44 (83%) healed by a scars. Healing of small and medium sized defects was excellent, they healed in 93.6%, while large defects only in 33.3%. Of 43 gastric ulcers after one month treatment 31 healed (72.1%) by a scar. Small and medium-sized defects healed in 80.5% and large ones only in 28.6%. With the exception of one case all were in an advanced stage of healing with a tendency of complete healing with scare formation.

The effect of administering low doses of famotidine or ranitidine alone or in combination with an M1-receptor-selective antagonist, pirenzepine, on night intragastric acidity was evaluated in 16 active duodenal ulcer patients to verify 1) whether anticholinergics and H2-antagonists have a synergic effect on inhibition of night gastric acidity, and 2) whether patients with vagal hypertone are more sensitive to anticholinergics than the remainder of the duodenal ulcer population. The endogastric pH was continuously recorded for 12 h (8 PM-8 AM) after random, single-blind administration of one of the following drug regimens: 20 mg famotidine, 150 mg ranitidine, 50 mg pirenzepine, 20 mg famotidine plus 50 mg pirenzepine, and 150 mg ranitidine plus 50 mg pirenzepine. Six patients with a basal acid output:peak acid output BAO:PAO greater than 0.3 were considered "vagal hypertone" subjects. Night gastric acidity inhibition was -39.6% with pirenzepine (p less than 0.001) and -73.7% and -71.5% with famotidine or ranitidine (p less than 0.001 vs. pirenzepine). The simultaneous administration of pirenzepine with famotidine or ranitidine provoked only a slight, insignificant increase in percent suppression, 5.1% and 6.3%, respectively, and did not modify either the time lag to onset of anti-H2 action or the duration of action. Patients with a BAO:PAO greater than 0.3 were not more sensitive to anticholinergic treatment than other duodenal ulcer patients. Our study furnishes evidence that combined administration of anti-H2 and anticholinergics is not significantly better than anti-H2 alone, in active duodenal ulcer patients.

Bilateral microinjections (0.2-2 nmol/site) of a potent M2 muscarinic receptor agonist, cis-methyldioxolane (CD), but not those of a relatively selective M1 receptor agonist (McN-A343; 3 nmol/site), into the intermediate portion of nucleus tractus solitarii (NTS) of pentobarbital-anesthetized rats elicited a decrease in blood pressure (23-52 mm Hg) and heart rate (16-50 bpm). Previous microinjections of a selective competitive M2 receptor antagonist (AFDX-116; 0.8 nmol/site), but not those of a potent selective M1 receptor antagonist (pirenzepine; 2 nmol/site), into the NTS blocked the effects of CD. These results indicate that the muscarinic receptors in the intermediate portion of NTS are of M2 type.

Seasonal accumulation of duodenal ulcer recurrences suggests that maintenance therapy could be limited to the more risky periods. We carried out a 2-year, multi-centre, randomized, double blind study in 250 patients in whom the last ulcer proved to be healed at the endoscopy on entry. One-hundred-and-twenty-six patients in group A were given pirenzepine 2 X 25 mg while 124 in group B had 2 X 50 mg daily from the beginning of January to the end of March, and from the beginning of September to the end of November for two consecutive years. Test endoscopies were performed each year at the end of February, May and November. Both groups proved to be well comparable. Thirty-five patients dropped out from group A in the first and 10 in the second year; in group B 27 and 29, respectively. As the effect did not show any dose relation, the four yearly cycles were summarized. Recurrence rate checked in May was 22.1% while in both pirenzepine protected months it was 11.3% (p less than 0.0005) and 13.4% (p less than 0.001), respectively. We conclude that pirenzepine administered in the risky seasons prevents the peak ulcer incidence and reduces the recurrence rate to a level lower than in the non-risky season. Thus pirenzepine is effective in ulcer prevention even if administered in an interrupted manner.