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In view of the results of animal studies as well as theoretical considerations, continuous administration of beta-lactam antibiotics should be superior to intermittent administration because of the close relationship between efficacy and the duration of time in which the concentration of unbound antibiotics in plasma remains above the MIC. The aim of the present study was to establish the pharmacokinetic parameters of cefamandole and ceftazidime for patients receiving these cephalosporins by continuous infusion. The interindividual differences in the concentrations in plasma at the steady state were mainly attributable to variations in renal function, as estimated by the rate of creatinine clearance. Using these results, we derived formulas for both cephalosporins that can be used to determine on an individual basis the total daily dose needed to obtain a therapeutic concentration in plasma. These formulas were tested with a group of subsequent patients and proved to be practical and fairly reliable. For some patients, a correction for a possible underestimation of the renal clearance at presentation might be required.

Twelve patients undergoing total hip replacement were given 600 mg of linezolid as a 20 min iv infusion along with conventional prophylaxis of 1 g of cefamandole immediately before surgery. Routine total hip arthroplasty was carried out, and at timed intervals during surgery samples of bone, fat, muscle and blood were collected for assay by high-performance liquid chromatography analysis. Samples of the haematoma fluid that formed around the operation site and further blood samples for assay were also collected at timed intervals following the operation. The penetration of linezolid into bone was rapid, with mean concentrations of 9.1 mg/L (95% CI 7.7-10.6 mg/L) achieved at 10 min after the infusion, decreasing to 6.3 mg/L (95% CI 3.9-8.6 mg/L) at 30 min. Correction for the simultaneous blood concentrations gave mean values for bone penetration of 51% at 10 min, 60% at 20 min and 47% at 30 min. Although the penetration of linezolid into fat was also rapid, mean concentrations and degree of penetration were c. 60% of those in bone; at 10 min they were 4.5 mg/L (95% CI 3.0-6.1 mg/L; penetration 27%); at 20 min they were 5.2 mg/L (95% CI 4.0-6.4 mg/L; penetration 37%); and at 30 min, 4.1 mg/L (95% CI 3.3-4.8 mg/L; penetration 31%). For muscle the corresponding values were 10.4 mg/L (95% CI 8.1-12.7 mg/L; penetration 58%) at 10 min, 13.4 mg/L (95% CI 10.2-16.5 mg/L; penetration 94%) at 20 min and 12.0 mg/L (95% CI 9.2-14.8 mg/L; penetration 93%) at 30 min. Mean concentrations of linezolid in the haematoma fluid drained from around the operation site were 8.2 mg/L at 6-8 h and 5.6 mg/L at 10-12 h after the infusion, and 7.0 mg/L at 2-4 h following a second 600 mg infusion given 12 h post-operatively. We conclude that linezolid exhibits rapid penetration into bone, fat and muscle of patients undergoing hip arthroplasty, to achieve levels in excess of its MIC for susceptible organisms (< or=4 mg/L); therapeutic concentrations were maintained in the haematoma fluid that surrounds the operation site for >16 h.

Thirteen patients undergoing total hip replacement were given ceftriaxone 1 g and cefamandole 1 g simultaneously, either immediately or 8 h before surgery. For both agents the concentrations seen in the bone and fat during the operation, and for haematoma fluid

To analyze unbound cefamandole in rat blood, a method combing microdialysis with microbore liquid chromatography has been developed. A microdialysis probe was inserted into the jugular vein/right atrium of male Sprague-Dawley rats to examine the unbound cefamandole level in the rat blood following cefamandole administration (50 mg/kg, i.v.). The dialysates were directly submitted to a liquid chromatographic system. Samples were eluted with a mobile phase containing acetonitrile-methanol-100 mM monosodium phosphate (pH 5.0; 15:20:65, v/v). The UV wavelength was set at 270 nm for monitoring the analyte. Using the retrograde method, at infusion concentrations of 1 microg/mL of cefamandole, the in vivo microdialysis recoveries were 55.44% for the rat blood (n = 6). Intra- and inter-assay accuracy and precision of the analyses were < or = 10% in the range of 0.1-10 microg/mL. Pharmacokinetic parameters were calculated from the recovery-corrected dialysate concentrations of cefamandole vs time data. The elimination half-life (t1/2,beta) was 21.6 +/- 1.6 min. The results suggest that the pharmacokinetics of unbound cefamandole in blood following cefamandole administration (50 mg/kg, i.v., n = 5) fit best to the two-compartmental model.

Quinupristin-dalfopristin (Q-D) is an injectable streptogramin active against most gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). In experimental endocarditis, however, Q-D was less efficacious against MRSA isolates constitutively resistant to macrolide-lincosamide-streptogram B (C-MLS(B)) than against MLS(B)-susceptible isolates. To circumvent this problem, we used the checkerboard method to screen drug combinations that would increase the efficacy of Q-D against such bacteria. beta-Lactams consistently exhibited additive or synergistic activity with Q-D. Glycopeptides, quinolones, and aminoglycosides were indifferent. No drugs were antagonistic. The positive Q-D-beta-lactam interaction was independent of MLS(B) or beta-lactam resistance. Moreover, addition of Q-D at one-fourth the MIC to flucloxacillin-containing plates decreased the flucloxacillin MIC for MRSA from 500 to 1,000 mg/liter to 30 to 60 mg/liter. Yet, Q-D-beta-lactam combinations were not synergistic in bactericidal tests. Rats with aortic vegetations were infected with two C-MLS(B)-resistant MRSA isolates (isolates AW7 and P8) and were treated for 3 or 5 days with drug dosages simulating the following treatments in humans: (i) Q-D at 7 mg/kg two times a day (b.i.d.) (a relatively low dosage purposely used to help detect positive drug interactions), (ii) cefamandole at constant levels in serum of 30 mg/liter, (iii) cefepime at 2 g b.i.d., (iv) Q-D combined with either cefamandole or cefepime. Any of the drugs used alone resulted in treatment failure. In contrast, Q-D plus either cefamandole or cefepime significantly decreased valve infection compared to the levels of infection for both untreated controls and those that received monotherapy (P < 0.05). Importantly, Q-D prevented the growth of highly beta-lactam-resistant MRSA in vivo. The mechanism of this beneficial drug interaction is unknown. However, Q-D-beta-lactam combinations might be useful for the treatment of complicated infections caused by multiple organisms, including MRSA.

Infection after open heart surgery is a serious complication since eradication of infection in these cases is difficult even with appropriate antibiotic therapy. In the attempt to avoid this problem, prophylactic administration of antibiotics is common. Their relative safety and their broad spectrum of activity make cephalosporin antibiotics popular choices for prophylaxis prior to and during operations, including cardiovascular procedures. METHODS. Preoperative antibiotic prophylaxis with 2 g cefamandole was performed in a prospective randomized study including 62 male patients divided into three groups. All patients gave informed consent, and the study was approved by the ethics committee of the hospital. Patients in group 1 (n = 21) and group 2 (n = 21) underwent aortocoronary bypass (ACVB) with extracorporeal circulation (ECC), while patients in group 3 (n = 20) had carotid surgery. Anaesthesia, coronary-bypass procedures and infusion regime were standardized. The flow rate during ECC was maintained at 2.41/min/m2 and the rectal temperature between 33 degrees and 34 degrees C. Arterial and urine specimens for the determination of plasma and urine levels of cefamandole were taken at definite times. Autologous blood salvage during operation was performed with haemofiltration techniques (HF) in group 1 (HF 80, Fresenius, Bad Homburg, Germany) and with cell separation techniques (CS) in group 2 (Hemonetics III, Hemonetics). Plasma and urine cefamandole levels were measured by high-pressure liquid chromatography (HPLC). RESULTS. After administration of 2 g cefamandole mean peak levels of 404.6 +/- 141.7 micrograms/ml were seen. Because of haemodilution at the beginning of extracorporeal circulation, group 1 and 2 showed much lower cefamandole plasma levels, 22.1 +/- 11.6 micrograms/ml and 24.3 +/- 14.4 micrograms/ml, than group 3 (after the same time course), with 47.4 +/- 19.1 micrograms/ml. For all patients in group 1 and 2 prebypass time (70.3 +/- 22.4 min) and the duration of the ECC (72.3 +/- 17.7 min) were comparable. There was a significant correlation between prebypass time and cefamandole plasma levels at the beginning of extracorporeal circulation (P < 0.001). No correlation could be seen for the plasma concentration after discontinuation of the extracorporeal circulation and the duration of extracorporeal circulation. The volume of autologous red packed cells and the enclosed amount of cefamandole showed a significant difference (P < 0.001) between group 1 (1120.0 +/- 296.8 ml, 27.5 +/- 17.1 mg) and group 2 (734.3 +/- 186.6 ml, 2.9 +/- 3.2 mg). The plasma cefamandole level after transfusion of autologous blood displayed a significant correlation (p < 0.01) with cefamandole concentration in the autologous red packed cells. Transfusion of the autologous blood produced no significant increase in plasma cefamandole levels. With an operation time of more than 2.5 h during ECC the cefamandole plasma level decreased below the necessary minimal inhibitory concentration (MIC90), particularly for gram-negative bacteria. CONCLUSION. Additional administration of 1 g cefamandole shortly before the beginning of cardiopulmonary bypass is recommended, particularly for surgical procedures with ECC of more than 2.5 h. Adjustment of drug dosage prior to or during surgery may be required to optimize therapy, but before this can be achieved precisely, more information on drug disposition during the operative procedures is needed.

The pharmacokinetics of prophylactic antibodies may differ in cardiac and aortic aneurysm surgery for at least two reasons: aortic aneurysm surgery generally entails a greater blood volume loss and replacement, and aortic aneurysm surgery usually does not require extracorporeal cardiopulmonary bypass. We prospectively studied two different cefamandole dosing regimens in patients undergoing aortic aneurysm surgery (phase 1, 1 gm intravenously at the induction of anesthesia; phase 2, 2 gm intravenously at the induction of anesthesia followed by 1 gm intravenously every 2 hours during surgery). In phase 1 and 2 plasma levels were measured at the time of skin incision, aortic cross-clamping, aortic unclamping, and skin closure. In phase 2 cefamandole elimination in urine and cell-saver effluent was also determined. An adequate plasma level of 10 micrograms/ml was maintained in only 4 of 14 patients in phase 1, but in 10 of 10 patients in phase 2. Cefamandole loss in cell-saver effluent was 136 +/- 100 mg, which was 13% of the measured renally excreted amount. As has been previously shown in cardiac surgery, a cefamandole prophylactic antibiotic regimen of 2 gm intravenously at the induction of anesthesia followed by 1 gm every 2 hours during surgery provides a dependable and practical dosing regimen in patients undergoing aortic aneurysm surgery.

A high-performance liquid chromatographic method with column switching has been developed for the simultaneous determination of cefamandole and cefamandole nafate in plasma and urine. The plasma and urine samples were injected onto a precolumn packed with Corasil RP C18 (37-50 microns) after simple dilution with an internal standard solution in 0.05 M phosphoric acid. Polar plasma and urine components were washed out using 0.05 M phosphoric acid. After valve switching, the concentrated drugs were desorbed in back-flush mode and separated by a reversed-phase C8 column with methanol-5 mM tetrabutylammonium bromide (45:55, v/v) as the mobile phase. The method showed excellent precision with good sensitivity and speed, and a detection limit of 0.5 microgram/ml. The total analysis time per sample was less than 30 min, and the mean coefficients of variation for intra- and inter-assay were both less than 4.9%. The method has been successfully applied to plasma and urine samples for human volunteers after intravenous injection of cefamandole nafate.

We compared the prophylactic use of cefamandole and ceftriaxone in 40 patients undergoing elective cardiac surgery. Postoperative wound infection occurred in one and two patients, respectively, in each group (n.s.), and bronchial superinfection in one patient in each group. In 12 additional patients drug concentrations in plasma and pericardial fluid were measured at different times following the administration of ceftriaxone. Plasma and pericardial fluid concentrations of ceftriaxone were above the minimal inhibitory concentration of susceptible microorganisms for up to 24 h after intravenous administration. We conclude, firstly, that the incidence of infection after cardiac surgery is low with both cefamandole and ceftriaxone prophylaxis. Secondly, efficient plasma and pericardial fluid levels of ceftriaxone last for up to 24 h after intravenous administration.

Twenty-three patients undergoing transurethral resection of the prostate for benign prostatic hypertrophy received antibiotic prophylaxis with a second generation cephalosporin, cefamandole, administered by a single IV bolus of 2.5 g. A pharmacokinetic study was performed on blood and resection chips collected at regular intervals. Cefamandole penetrates rapidly into the prostate without any saturation threshold. It diffuses less extensively and persists for a shorter period in elderly subjects, but penetrates to an identical degree regardless of the volume of the adenoma. The prostatic concentration was always higher than the minimal inhibitory concentration for the bacteria generally encountered, except for pseudomonas. The pharmacokinetic study of cefamandole therefore demonstrated that an IV bolus of 2.5 g is perfectly suitable for antibiotic prophylaxis prior to prostatic resection.

A randomized, prospective, double-blind study was designed to compare intravenous administration with intrauterine irrigation using an extended half-life (t1/2 = three hours) cephalosporin, ceforanide. Patients included in the study had a nonelective cesarean section with rupture of membranes for three hours or longer. Sixty-four patients received a single dose of ceforanide immediately after clamping the umbilical cord. Patients were similar in both groups in age, weight, length of labor, and duration of ruptured membranes. The group receiving the intravenous ceforanide had a significantly shorter duration of surgery than the patients receiving the intrauterine ceforanide. Endometritis infection rates were similar, 11.8% (intravenous) versus 11.1% (intrauterine), P greater than .1. Serum levels were as much as tenfold higher in the intravenous group versus the intrauterine group. Intrauterine irrigation with an antimicrobial agent provided no advantage over systemic administration.

We describe a "high-performance" liquid-chromatographic assay for quantifying cefamandole in biological fluids from patients with renal impairment. Serum samples are deproteinized with acetonitrile, then extracted with dichloromethane; dialysis-fluid samples are injected directly; urine samples are diluted appropriately before injection onto the reversed-phase column. The mobile phase is a methanol/aqueous solution (31/69 by vol) containing 500 microL of phosphoric acid, 20 mmol of sodium sulfate, and 200 microL of triethylamine per liter, the mixture being adjusted to pH 6.0 with NaOH. Retention time for cefamandole is 12 min. Its peak is well resolved in highly contaminated samples from renally impaired subjects. The assay's selectivity, reproducibility (within-day and between-day CVs less than 8% in all three sample fluids), and sensitivity--0.5 mg/L in serum, 1.0 mg/L in dialysis fluid, and 5.0 mg/L in urine--make it applicable to pharmacokinetic studies.

Antibiotic prophylaxis in open-heart operations is a widely accepted practice. Introduction of new antibiotics with differences in tissue distribution, spectrum of activity and therapeutic index prompts their evaluation as possible effective prophylactic agents. We compared the distribution, clinical efficacy, and safety of ceforanide with cephalothin as a prophylactic agent in coronary artery bypass graft (CABG) procedures. The results indicated that the intravenous administration of ceforanide at the dose of 1 gm every 12 hours for 2.5 days was equivalent to cephalothin 1 gm every 6 hours for 2.5 days. Serum, muscle, and bone concentrations of ceforanide were significantly greater than those of cephalothin. These concentrations consistently exceeded the minimal inhibitory concentration for Staphylococcus aureus, the major pathogen implicated in wound infections. No toxicty was observed with either antibiotic. Ceforanide merits consideration as a prophylactic antibiotic in CABG operations.

The pharmacokinetics of cephamandol administered intramuscularly in single doses of 5 or 20 mg/kg and intravenously in a single dose of 5 mg/kg was studied on rabbits. When the antibiotic was administered intramuscularly, a one-compartment model was used for determination of the parameters of the antibiotic pharmacokinetics in the blood serum, while on intravenous administration of the antibiotic a two-compartment model was used. It was found that the rate of cephamandol elimination after intramuscular administration did not depend on the drug dose. The antibiotic half-life was 34-37 minutes. The apparent volume of the antibiotic distribution after intramuscular administration was 0.31-0.71 ml/g. After intravenous injection of cephamandol the apparent volume of its distribution in the central compartment was 0.27 ml/g. The stationary and kinetic volumes of the antibiotic distribution were 0.36 and 0.46 ml/g, respectively. The average values of the antibiotic elimination constant, the constant of the antibiotic passage from the central compartment to the peripheral one and vice versa were 0.0446, 0.0193 and 0.0546 min-1, respectively. After intravenous injection the rate of cephamandol elimination from the rabbit blood was higher: the antibiotic half-life after intravenous injection was 26.1 min.

Eight healthy male volunteers received 1 g of either ceftazidime or cefamandole as an intravenous infection. Serial blood samples were taken over the next 8 h. Urine samples were collected over 24 h. Levels of these antibiotics were measured in the fluid of blisters resulting from application of cantharides. The concentration of ceftazidime in serum at 0.25 h after intravenous injection was 83.3 micrograms/ml. The serum half-lives for the respective drugs were 1.8 and 0.8 h. The mean apparent volume of distribution of ceftazidime (13.6 liters) was greater than that of cefamandole (9.8 liters). Plasma clearance was 111 ml/min for ceftazidime and 216 ml/min for cefamandole. The maximum blister fluid concentration of ceftazidime was 45.9 micrograms/ml, and that of cefamandole was 22.1 micrograms/ml. The relative availability of each drug in blister fluid compared with serum was similar.

The pharmacokinetics of cefamandole during standard or pulsatile cardiopulmonary bypass were studied in 13 adult cardiac surgery patients. All patients received 20 mg/kg of cefamandole intravenously at midnight before surgery, 6 AM on the morning of surgery and just prior to the initiation of cardiopulmonary bypass (CPB) surgery. Serum, skeletal muscle, and fat samples were taken at the beginning of CPB and at 30-minute intervals thereafter and assayed for cefamandole concentration. The average elimination rate constant and elimination half-life for cefamandole in patients undergoing standard CPB were 0.73 +/- 0.09 hour-1 and 0.94 +/- 0.11 hour, respectively. In contrast patients undergoing pulsatile CPB had significantly slower elimination rate constants (0.50 +/- 0.1 hour-1 and 1.4 +/- 0.28 hours, respectively; P less than or equal to .05). Area under the curve (AUC) values for cefamandole in fat and muscle tissue were higher in patients undergoing pulsatile CPB, but the differences were not statistically significant. Prolonged elimination from the serum, skeletal muscle, and adipose tissue, as compared with normal subjects, is seen with both pulsatile and standard CPB but is greater for the pulsatile method. Intraoperative dosing of cefamandole is required to maintain adequate serum and tissue levels for operations lasting longer than 4 or 6 hours in which standard or pulsatile CPB, respectively, are used.

Plasma levels of antibiotics often do not correlate well with their tissue levels. To determine optimal antibiotic coverage for prophylactic effect in vascular surgery, we studied the tissue pharmacokinetics of four cephalosporins in dogs: cefazolin, cefoxitin, cefamandole, and moxalactam for 3 hours after a single (25 mg/kg) intravenous injection. The minimal inhibitory concentration (MIC) of these antibiotics for the three most common pathogens involved in graft infections (Staphylococcus aureus, S. albus, and Escherichia coli) and their tissue concentration (TC) in the plasma, muscle, subcutaneous tissue, and aortic wall were assayed. The data are presented as TC/MIC ratio. Cefoxitin and moxalactam failed to achieve an effective therapeutic TC/MIC ratio (greater than 10) for S. aureus and S. albus in all the tissues studied whereas cefoxitin and cefamandole were above therapeutic levels. All antibiotics achieved an effective therapeutic ratio against E. coli, but cefamandole performed better (p less than 0.05) than cefoxitin; the latter reached effective levels at 3 hours. Cefamandole attained the most effective bioactive aortic tissue levels when the three most common pathogens were considered together and should therefore be considered as an antibiotic agent of choice for prophylaxis in vascular surgery.

This investigation evaluated the effect of probenecid on ceforanide concentrations in eight healthy volunteers. Each volunteer was given 1 or 2 g of ceforanide either alone or with 1 g of probenecid. Concentrations of ceforanide in plasma, urine, and saliva were then measured. Probenecid did not alter the plasma concentrations of ceforanide, nor did it affect the urinary excretion of this agent. Ceforanide was not secreted into saliva in any detectable amount either when administered alone or with probenecid. It is not clear why probenecid has a negligible effect on ceforanide concentrations in plasma. It may be that tubular secretion plays less of a role in the excretion of ceforanide than expected, or that the physical properties of ceforanide prevent probenecid from affecting its excretion.

In 24 patients undergoing open-heart operation, 2 gm of cefamandole was administered intravenously by bolus technique at various time intervals prior to operation. Samples of pericardial fluid, atrial appendage tissue, and serum were obtained simultaneously in order to compare antibiotic levels in these sites as a function of time. All samples were microbiologically assayed by disc diffusion. Using linear regression analysis, the atrial appendage and serum half-lives for cefamandole were 36 and 38 minutes, respectively. At 40 minutes, peak levels of cefamandole were observed both in pericardial fluid and in atrial appendage tissue. The peak concentrations of cefamandole were 50 micrograms/gm in atrial appendage and 25 micrograms/ml for free drug content in pericardial fluid. These amounts were appreciably above the mean minimum inhibitory concentration of cefamandole for penicillin-resistant staphylococci, the usual pathogens grown in infections following implant operation.

We used cefamandole in the initial treatment of 34 children (10 months to 15 years of age) with suspected bone, joint, or soft tissue infections. The minimal inhibitory concentration of organisms encountered ranged between 0.015 and 2 microgram/ml. At 1 h after intravenous infusion of 25 mg/kg, the mean serum level of cefamandole was 26.2 microgram/ml (range, 8.9 to 47.5 microgram/ml), and at 3 h the level was 1.8 microgram/ml (range, 0.6 to 4.4 microgram/ml), which is above the minimal inhibitory concentration for most of the organisms encountered. However, when the drug was given intravenously every 6 h, the mean level after a 37-mg/kg dose was 0.9 microgram/ml (range, less than 0.5 to 1.9 microgram/ml) at 4 h and, by extrapolation, would have fallen below 0.1 microgram/ml at 6 h. The mean serum half-life was 34 min. Cefamandole appeared to diffuse well into synovial fluid, with joint fluid levels between 5 and 40 microgram/ml. The drug was tolerated well. Cefamandole appears to be a reasonable alternative in the initial treatment of skeletal infections in children, but need to be administered every 4 h to maintain suprainhibitory serum levels between doses.

The pharmacokinetics of Cefamandole was studied in 17 patients with terminal renal impairment, 10 of which were undergoing sessions of hemodialysis while 7 were in the period between dialysis sessions. An open two-compartment kinetic model was used to describe the bi-phasic decrease of the plasma concentrations of Cefamandole thus establishing the amounts of the antibiotic in the peripheral and central compartments together with the amount eliminated. All patients received an i.v. bolus injections of 15 mg/kg body weight. During the hemodialysis sessions, the pharmacokinetic parameters of Cefamandole were the following: alpha = 5.006 hr-1 beta = 0.182 hr-1 K12 = 2.598 hr-1 K21 = 2.147 hr-1 K13 = 0.441 hr-1 Vc = 5.700 l Vp = 6.190 l Vdss = 11.94 l It may be seen that there is a decrease in the overall elimination constant compared with that obtained during the periods between the dialysis sessions. A dosage regimen of multiple doses is established as a function of the pharmacokinetic parameters of the antibiotic for patients with terminal renal impairment undergoing periodic sessions of hemodialysis.

We compared the safety and efficacy of a six-dose regimen of cephalothin with a two-dose regimen of ceforanide for the prevention of infection after elective vaginal hysterectomy. A total of 150 patients were randomly assigned to either regimen. The overall incidence of documented pelvic infection was 5.3% and did not differ significantly between the prophylaxis groups when stratified by type of surgery. No serious adverse reactions were encountered in either group, but phlebitis was significantly more common in patients receiving cephalothin. We conclude that a two-dose regimen of ceforanide given intramuscularly is as effective as, and possibly better tolerated than, a six-dose regimen of cephalothin.

Cefonicid (15 mg/kg) was administered intravenously at a constant rate of infusion over 15 min to 10 geriatric patients (mean age, 77 years) and to 4 young subjects (mean age, 35 years). Model-dependent and noncompartmental pharmacokinetic parameters were calculated and found to be congruous; noncompartmental data are reported. Significant differences in the values for area under the curve, mean residence time, total body clearance, and renal clearance were observed between the geriatric and young groups. Mean elimination half-life values were 9.59 and 4.88 h for the geriatric and young groups, respectively. Total body and renal clearances were inversely correlated to age and directly correlated to creatinine clearance. Free fraction was not correlated to albumin concentration but was correlated exponentially to total cefonicid concentration. Despite the prolonged half-life values observed in our geriatric patients, the difference in mean trough concentrations was slight. Daily administration of a 15-mg/kg dose should provide adequate concentrations in serum and should not produce appreciable accumulation in geriatric patients.

The role of prophylactic antibiotic lavage in elective biliary tract operations is controversial. To investigate this question, a prospective, randomized study was undertaken between 1979 and 1983. All patients more than 18 years of age who underwent elective biliary operations were included. Eighty-eight patients were enrolled in the study and were stratified into the following antibiotic groups: (1) cefamandole nafate 2 gm administered intravenously preoperatively and 6 hours postoperatively in four doses; (2) cefamandole nafate 0.4% solution: 250 ml to irrigate the abdominal wound on opening, 500 ml to irrigate the peritoneal cavity, and 250 ml to irrigate the wound on closing; and (3) systemic plus topical administrations as in Nos. 1 and 2. Age, sex, type of operation, and underlying diseases were comparable in all groups. The patients were then evaluated for postoperative infections. In the intravenous cefamandole group there was only one patient who developed a urinary tract infection after operation. In the topical cefamandole group there were four postoperative infections: wound-one, urinary tract--two, and cholangitis--one. In the intravenous plus topical cefamandole group there were four postoperative infections: wound--one, urinary tract--two, and pneumonia--one. No deaths occurred in any group. Blood, subcutaneous, and peritoneal drug levels were sampled 1 hour after opening and before closing. Therapeutic serum levels of cefamandole are 1 to 16 micrograms/ml and adequate serum levels were achieved in all groups. However, higher levels were obtained in the subcutaneous tissue and peritoneum when topical cefamandole was used. We conclude: (1) Topical cefamandole lavage alone is adequate prophylaxis in elective biliary operations and achieves comparable results as perioperative systemic administration; (2) topical cefamandole resulted in higher subcutaneous tissue and peritoneal levels than intravenous cefamandole and also achieved therapeutic serum levels; and (3) there is no advantage to the use of systemic plus topical antibiotics in elective biliary operations.

In two groups of patients undergoing coronary artery bypass grafting (CABG), two different regimens of antibiotic prophylaxis with cefamandole nafate were compared. In Group 1, 30 mg per kilogram of body weight was administered intravenously during induction of anesthesia. In Group 2, a second dose of 15 mg/kg was administered intravenously shortly before cannulation. Serum and tissue levels in the right atrium, the pericardium, and the sternum were determined using high-pressure liquid chromatography. The results showed that in Group 2 the serum levels were significantly higher from 48 minutes onward after induction and remained at an acceptable level during CABG. The tissue levels in the sternum and pericardium were also significantly higher in Group 2 compared with Group 1. It is concluded that a second dose of cefamandole (15 mg/kg) shortly before the beginning of cardiopulmonary bypass is recommended, particularly for high-risk patients.

Two hundred twenty patients were randomly assigned to receive either ceforanide or cephalothin as perioperative antibiotic prophylaxis during cardiovascular surgery. More infections were seen among cephalothin recipients (8 deep, 32 total) than among ceforanide recipients (1 deep, 17 total). Among patients who had only coronary artery bypass grafting, more cephalothin recipients had infection than did ceforanide recipients (19 of 82 as opposed to 7 of 83; p = 0.001; relative risk, 2.7; 95% confidence interval, 1.22 to 6.18). The difference between the two regimens was attributable to fewer blood, wound, and urinary tract infections. Among patients who had other procedures, there was no difference in the efficacy of the two regimens. Cephalothin recipients who developed wound or blood stream infections had lower antibiotic levels in their atrial appendages than recipients not developing such infections (p = 0.02). If one assumes that cephalothin does not increase the risk of infection, then these data show that antibiotic prophylaxis prevents infection after coronary artery bypass surgery, and, in the dosages used, that ceforanide is superior to cephalothin.

After double-blind controlled studies demonstrated cefamandole nafate irrigation of the uterus during cesarean section to be effective in reducing the rate of endomyometritis, antibiotic irrigation was adopted as a standard procedure at Tripler Army Medical Center. The present study analyzes the outcome in patients undergoing cesarean section before (comparison group) and after (treatment group) routine use of antibiotic irrigation began. The incidence of endomyometritis in 100 patients from the comparison group was 20% and in 298 patients from the treatment group 1.7% (P less than .0001). Serum analysis for cefamandole nafate demonstrated little systemic absorption of the antibiotic. Cefamandole nafate intrauterine irrigation at cesarean section effectively prevents endomyometritis.

The pharmacokinetic characteristics of cefamandole were determined after intravenous administration of a 1-Gm dose to 10 subjects with normal renal function, 10 patients with stabilized renal failure, and five chronic nephritic patients included in a intermittent hemodialysis program. In normal subjects, biological half-life (t1/2) averaged 0.94 hour, the overall elimination rate constant (Ke) was 0.7378 (hr-1), total clearance (Ct) was 223 ml/min/1.73 m2, renal clearance (Cr) was 164 ml/min/1.73 m2, and urine recovery of cefamandole over the 6 hours following a dose amounted to 74 per cent of the administered dose. In patients with stabilized renal failure and in patients on hemodialysis, biological half-life was markedly increased, with a theoretical value of 10.4 hours in case of a creatinine clearance of zero. The amount of antibiotic extracted over a 6-hour dialysis period accounted for 29 per cent of the cefamandole present in the vascular compartment at the beginning of the dialysis procedure. A significant correlation was established between the values of Ke and creatinine clearances, Ccr: Ke = 0.0289 + 0.0063Ccr (r = 0.937). This relationship was used to calculate the loading dose (LD), maintenance doses (D), and dosage intervals (tau) with regard to renal function. From these data recommendations regarding the adjustment of cefamandole dosage to the renal status can be made.

The activities of cefamandole, cephalothin, ampicillin, and chloramphenicol were compared in fulminant and temperate Escherichia coli meningitis in rabbits. Intensive dosing schedules were employed to achieve maximal therapeutic benefits with short-term treatment. In an 8-h schedule chloramphenicol was significantly more effective in sterilizing the cerebrospinal fluid and curing both fulminant and temperate infections than cefamandole or ampicillin. Cephalothin was without effect in fulminant meningitis. Cefamandole and ampicillin were equivalent in activity in this and longer (12- and 24-hr) treatment schedules. The therapeutic benefits of chloramphenicol were purchased via use of doses above those generally regarded as safe for human use. The mean serum, cerebrospinal fluid, and brain concentrations of chloramphenicol, cefamandole, and ampicillin were significantly greater in rabbits with fulminant meningitis than in those with temperate meningitis. The difference was of such magnitude as to support the need to monitor drug concentrations.

SK&F 75073, a new parenteral cephalosporin, was found to have broad in vitro and in vivo antibacterial activity including isolates usually resistant to cephalothin and cefazolin. This activity included indole-positive Proteus and Enterobacter species and some Serratia isolates. Proteus mirabilis strains were particularly susceptible, as were Haemophilus influenzae and Neisseria species. The activity of SK&F 75073 against gram-positive bacteria was poorer than that of the control cephalosporins. This cephalosporin is highly bound to serum proteins, and a loss in in vitro activity was observed in the presence of serum. Parenteral administration of SK&F 75073 to experimental animals (mice, dogs, squirrel monkeys) resulted in high and prolonged serum levels when compared with cefazolin and other injectable cephalosporins. This favorable serum profile was reflected in the excellent protection observed in mice infected with pathogenic bacteria.

1) Tissue concentrations of cefamandole (CMD) one hour after the end of 2 g/30 approximately 60 minutes drip infusion were 7.3 approximately 13.1 microgram/g in uterus, ovary and oviduct. These concentrations were higher than MICs of 70 approximately 100% of causative organisms, including Staphylococcus aureus, Escherichia coli, Klebsiella, Proteus mirabilis, Enterobacter and Citrobacter, isolated from the infections in the field of obstetrics and gynecology. 2) CMD was administered to 14 patients with moderate infections in the field of obstetrics and gynecology at a daily dose of 4 g for 5 approximately 7 days. The overall clinical efficacy obtained was as follows; excellent in 7 cases (50%), good in 3 cases (21%) and poor in 4 cases (29%). 3) Antimicrobial activity of CMD against causative organisms resembled that of CEZ. 4) No adverse effects and abnormal laboratory findings were observed. From the above, we considered that CMD was an effective and safe antibiotic against infections in the field of obstetrics and gynecology.

The kinetics of cefamandole during cardiac surgery was studied in 16 adult patients given a single intravenous infusion of 20 mg/kg at the time of anesthesia induction. Five normal volunteers who received the same dose served as controls. Cardiopulmonary bypass (CPB) was found to signficantly increase the half-life (t 1/2) of cefamandole. The mean t 1/2 during CPB (113.2 min) was longer than the terminal t 1/2 in normal volunteers (52.0 min; p less than 0.005). Throughout CPB (maximum, 3,7 hr), cefamandole plasma levels were maintained above the minimum inhibitory concentration for those organisms most likely to cause postoperative infections. We conclude that if 20 mg/kg of cefamandole is given within an hour of the beginning of cardiovascular surgery, a supplemental dose is not needed until the patient has been on CPB for at least four hours.

An investigation was carried out into the effectiveness of cefamandole as compared to that of cephalothin against methicillin-sensitive and methicillin-resistant strains of Staphylococcus aureus both in vitro and in mice with the experimental peritonitis-induced septicaemia as a model for a generalized infection. In the agar-diffusion test 95% of 118 and in the broth-dilution test 80% of 30 methicillin-resistant strains were sensitive to cefamandole. In experimental infections the ED50 with methicillin-resistant strains was 20 times greater than that required for the methicillin-sensitive strain although the MIC was only twice that for the latter. Doses of cephalothin required for treatment of infections due to methicillin-resistant strains were also twenty times greater than for those due to the methicillin-sensitive strain. But these differences were consistent with those in MIC (by factors of 16-32). Thus, the results of in-vitro testing of cefamandole are not predictive for its therapeutic efficacy in staphylococcal infections with methicillin-resistant strains. Therefore, rather than relying on inhibition zone diameter and MIC, the information that a staphylococcal strain is methicillin-resistant should be used as an indication not to choose cefamandole for chemotherapy.

The pharmacokinetics of cefonicid were investigated in eight healthy adults. A one-gram dose was administered either intramuscularly or intravenously in a cross-over design study. Mean peak cefonicid plasma concentrations of 186 to 204 mcg/ml and 88 to 123 mcg/ml were achieved after intravenous and intramuscular injection, respectively, with elimination half-lives of 4.9 h and 5.3 h. Cefonicid concentrations were measured by both microbiological (M.A.) and high-performance liquid chromatography (HPLC) assays. Results were quite similar with the two techniques, except for the urinary recovery of cefonicid in the first 24 hours (83% of the dose with MA - vs 53% with HPLC method). The apparent volume of distribution (Vd area) was 0.18 1/kg; the total body clearance (CT) and the renal clearance (CR) were 24-26 ml/min and 15-19 ml/min, respectively. The kinetic data of cefonicid were not significantly different for the two routes of administration. A one-gram i.v. or i.m. cefonicid dose produced high and prolonged plasma concentrations with a longer half-life than obtained with commonly used cephalosporins.

Because cerebrospinal fluid (CSF) antibiotic levels fail to predict either clinical success or relapse in the treatment of bacterial meningitis, we examined simultaneous antibiotic concentrations in the blood, brain, and CSF of control rabbits and of animals with experimental pneumococcal meningitis. Cefamandole pharmacokinetics were analyzed in detail and compared with those of cephalothin, ampicillin, penicillin G, and tobramycin. After 4 h of continuous intravenous infusion, cefamandole reached concentrations in both brain and CSF in excess of the minimal bactericidal concentration for the test organism and compared favorably with ampicillin and penicillin in achieving bacteriological cure. Cephalothin levels in the central nervous system remained undetectable in both control and infected animals during this time. Tobramycin concentrations were measurable in the CSF, but not in brain tissue in association with an inflammatory stimulus.

Cefonicid was administered intramuscularly 1 h before open-heart surgery to seven patients in doses of 1 g each and to six patients in doses of 2 g each. Cefonicid concentrations were measured in the right atrial biopsy and in serum at onset of surgery, at time of atrial biopsy, 15 min after starting cardiopulmonary bypass, and at completion of cardiopulmonary bypass. Concentrations in the atrial biopsy and in serum at all periods exceeded the minimal inhibitory concentrations for organisms most frequently responsible for postoperative infections.

The penetration of cefamandole and ampicillin into the cerebrospinal fluid of rabbits with and without pneumococcal meningitis was evaluated. In normal animals, a mean maximum concentration of 0.22 +/- 0.13 microgram of cefamandole per ml was measured in the spinal fluid after a dose of 150 mg/kg given intramuscularly; with 25 and 50 mg/kg doses, no antibiotic was detected in the cerebrospinal fluid. With ampicillin, in intramuscular doses of 200 and 300 mg/kg, the mean maximum concentrations encountered in the cerebrospinal fluid were 1.59 +/- 0.4 and 1.47 +/- 0.44 microgram/ml, respectively. Penetration of cefamandole, and to a lesser extent ampicillin, was increased after 24 h of experimental meningitis. With cefamandole, the concentration of drug in the cerebrospinal fluid exceeded the usual inhibitory concentration for Haemophilus influenzae only with the 150 mg/kg dose. After 48 h of meningitis, there was a trend toward higher levels of antibiotic in the cerebrospinal fluid, but the difference between animals infected 24 versus 48 h was not statistically significant. In animals with meningitis, serum concentrations after 150 mg of cefamandole per kg and both ampicillin doses studied were 32 to 38% lower than the serum levels achieved in normal rabbits after identical doses of antibiotic.

The disposition of cefonicid (2 g intravenously every 24 h) was assessed in 15 patients with skin and skin structure infections. Trough and peak concentrations in serum were measured on two successive days to verify the attainment of steady state; and 1 trough and 12 postdose values of the concentration in serum were collected on the following day. Cefonicid concentrations in serum were determined by high-performance liquid chromatography. The cefonicid serum concentration versus time profile after intravenous infusion was clearly biexponential in all patients. The terminal elimination half-life determined by nonlinear regression analysis was 4.63 +/- 1.49 h (mean +/- standard deviation). The steady-state volume of distribution and total body clearance were 0.12 +/- 0.04 liter/kg and 0.369 +/- 0.110 ml/min per kg, respectively. These results are comparable to parameters derived from previous studies in noninfected normal volunteers. Thus, the disposition of cefonicid is not altered in patients with severe skin and skin structure infections.

The ability of cefamandole to cross osseous capillary membranes and its concentrations in interstitial fluid spaces are studied in canine cortical bone. Extraction studies were performed by using indicator dilution techniques and demonstrated that cefamandole readily traversed osseous capillary membranes. Volume-of-distribution studies demonstrated that cefamandole was distributed in the plasma and interstitial fluid spaces of cortical bone. There was a direct correlation between the calculated concentrations of cefamandole in the interstitial fluid spaces of bone and the simultaneous serum levels determined by bioassay in animals in which a steady-state equilibrium had been achieved. This suggests that the less expensive and more readily available serum bioassay technique is more useful than bone bioassays in monitoring the osseous concentrations of cefamandole.

From 21 patients with prostatic adenoma with an average age of 69 years, serum and prostatic tissue concentrations after a single i.v. dose of 2 grams of cefamandole were estimated. The mean serum concentrations 30 minutes after the infusion was completed, were measured with 104.8 and after 60 minutes with 51 microgram/ml. The corresponding concentrations in the prostatic adenoma tissue were after 30 minutes 32.87 and after 60 minutes 17.1 microgram/g. These data are compared with earlier findings with other caphalosporine antibiotics (cephradine, cephapirine, cephacetrile, cephalothin) in the same tissue materials at the same time points. The estimated concentrations of cefamandole in serum and prostatic tissue are suited for the treatment of infections caused by cefamandole sensitive microorganisms.

35 males and 23 females with skin and soft tissue infection, lower respiratory tract infection, urinary tract infection or septicemia with known etiology were treated with cefamandole nafate. The patients were to a large extent (30%) alcoholics and/or drug abusers. Cefamandole was given intravenously as 4 daily doses of 1 g in 52 cases and of 2 g in 6 cases for 8 to 16 (mean 10) days. The effect was considered to be good in 40 patients (70%). Adverse reactions, mostly slight and transient, were seen in 22 patients (38%). Peak serum levels varied from 26 to 82 (mean 50) micrograms/ml after 1 g doses and from 68 to 100 micrograms/ml after 2 g. Previous statements of a better in vitro activity of cefamandole than of older cephalosporins against some gram-negative bacilli were corroborated.

Cefamandole nafate was effective in the treatment of a variety of infections caused by Staphylococcus aureus, Streptococcus pyogenes group A, Streptococcus pneumoniae, and Haemophilus influenzae in infants and children. The infections included periorbital cellulitis and ethmoiditis, bacteremia, cellulitis, pneumonia, and lymphadenitis. In vitro, cefamandole was effective in inhibiting the growth of H. influenzae isolated from blood or cerebrospinal fluid of patients with meningitis or sepsis. In two patients rash developed and cefamandole was discontinued. Other significant adverse effects were not noted.