Cefotaxime

Cefotaxime is a new 'third generation' semisynthetic cephalosporin administered intravenously or intramuscularly. It has a broad spectrum of activity against Gram-positive and Gram-negative aerobic and anaerobic bacteria, and is generally more active against Gram-negative bacteria than the 'first' and 'second generation' cephalosporins. Although cefotaxime has some activity against Pseudomonas aeruginosa, on the basis of present evidence it cannot be recommended as sole antibiotic therapy for pseudomonal infections. However, cefotaxime has been effective in treating infections due to other 'difficult' organisms, such as multidrug-resistant Enterobacteriaceae. Like other cephalosporins, cefotaxime is effective in treating patients with complicated urinary tract and lower respiratory tract infections, particularly pneumonia caused by Gram-negative bacilli. High response rates have also been achieved in patients with Gram-negative bacteraemia. Although favourable clinical results have been obtained in patients with infections caused by mixed aerobic/anaerobic organisms (such as peritonitis or soft tissue infections), the relatively low in vitro activity of cefotaxime against Bacteroides fragilis may restrict its usage in situations where this organism is the suspected or proven pathogen. In preliminary studies, males and females treated with a single intramuscular dose of cefotaxime for uncomplicated gonorrhoea caused by penicillinase-producing strains of Neisseria gonorrhoeae responded very favourably. Encouraging results have also been reported in open studies in children including neonates, treated with cefotaxime for meningitis and various other serious infections. In some situations, cefotaxime has been given in combination with another antibiotic such as an aminoglycoside, but the merits of such a combination have not been clearly established. Whether cefotaxime alone is appropriate therapy for conditions previously treated with aminoglycosides (other than pseudomonal infections) also needs additional clarification, but if established as equally effective in such conditions cefotaxime offers potentially important clinical and practical advantages in its apparent lack of serious adverse effects and freedom from the need to undertake drug plasma concentration monitoring.

Cefotaxime sodium, a parenteral cephalosporin antibiotic, exerts its bactericidal action through inhibition of bacterial cell wall synthesis. Chemical structure modifications have enabled this compound to be resistant to the action of Richmond I, III, IV, and V beta-lactamase enzymes. Excellent activity against many gram-negative bacilli, especially Enterobacteriaceae, has been demonstrated. Antipseudomonal activity is generally poor, however. Activity against gram-positive cocci, with the notable exception of Streptococcus fecalis, is adequate. Anaerobic activity is variable, particularly against Clostridia and Bacteroides species. Acute, subacute, and chronic toxicity studies in animals were generally unremarkable. No mutagenic effects or reproductive toxicity have been noted in animals. In man, cefotaxime is desacetylated to a microbiologically active metabolite. Urinary excretion is approximately 50-60% and 15-20% of a dose for the parent compound and desacetyl metabolite, respectively. The elimination half-life of cefotaxime is about one hour, with the total body clearance being approximately twice that of the renal clearance. Severe renal dysfunction causes a prolongation of the elimination half-life of cefotaxime and particularly desacetyl cefotaxime. A relatively low degree of protein binding in part attributes to a wide bodily distribution of cefotaxime. Cefotaxime is effective in a variety of infectious processes caused by susceptible organisms. Local reactions at the injection site and hypersensitivity phenomena are the most common adverse effects. Comparative trials attesting to cefotaxime's clinical utility over other parenteral cephalosporins or amino-glycosides are very limited. Based on the available evidence, cefotaxime should be most useful in combating serious gram-negative infections, because of its excellent activity against most of these organisms and its low toxicity profile.

Objective:To characterize the pharmacokinetics of cefotaxime and desacetylcefotaxime in pediatric patients undergoing continuous ambulatory peritoneal dialysis (CAPD) after intraperitoneal administration of cefotaxime.Design:Case series.Setting:Ambulatory children from Children's Hospital nephrology clinic, Columbus, Ohio.Patient population:Two adolescents without peritonitis.Methods:A single intraperitoneal dose of cefotaxime 500 mg per 1 L dianeal was given during CAPD. Cefotaxime and desacetyl-cefotaxime were measured in plasma, urine, and dialysate by HPLC.Results:Maximum plasma concentration (Cmax) of cefotaxime was 11.94 and 13.08 mg/L and that of desacetylcefotaxime 5.73 and 5.33 mg/L. Time to reach maximum concentration (Tmax) of cefotaxime was 2.22 and 4.08 h, and that of desacetylcefotaxime was 5.33 and 5.73 h after instillation of the intraperitoneal cefotaxime dose. Systemic absorption of cefotaxime was 56.6 and 64.8 percent. Total clearance of cefotaxime was 62 and 79 mL/min/1.73 m2. Nonrenal clearance accounted for nearly 95 percent; renal and CAPD clearance contributed approximately 5 percent of the total clearance. Renal and CAPD clearance measurements of desacetylcefotaxime were similar to those for cefotaxime. Cefotaxime half-life was 1.83 and 2.49 h and desacetylcefotaxime half-life was 8.14 and 11.0 h.Conclusions:Cefotaxime was well absorbed and therapeutic serum concentrations were achieved after intraperitoneal administration. Renal and CAPD clearances for cefotaxime and desacetylcefotaxime were low. Cefotaxime nonrenal clearance was unaffected. Further studies are needed to establish appropriate intraperitoneal dosing guidelines of cefotaxime in pediatric CAPD patients.