Probenecid Cefotaxime

Spectinomycin 2 g IM once, or ceftizoxime 500 mg IM once, or cefotaxime 500 mg IM once, or cefoxitin 2 g IM once with probenecid I g po once, or gatifloxacin 400 mg po once, or lomefloxacin 400 mg po once, or norfloxacin 800 mg po once plus... 

Urinary excretion is the major elimination path for most cephalosporins. When prescribing cephalosporins to patients with renal failure, practitioners must consider dose reduction or dose interval extension (Table 45.2). Renal tubular secretion contributes to the elimination of some cephalosporins, and an increase in cephalosporin plasma concentrations may occur when probenecid blocks renal tubular secretion of cephalosporins. Biliary elimination is important for some cephalosporins. Cefmetazole, cefoperazone (Cefobid), cefoxitin, and ceftriaxone achieve biliary concentrations greater than those in plasma. After parenteral administration of cefoperazone, 70% of the dose appears in the bile within 24 hours. Practitioners should decrease the dose of cefoperazone when prescribing for patients with hepatic failure or biliary obstruction. Metabolism is not a major elimination path for most cephalosporins. Cefotaxime is one of the few cephalosporins having an active metabolite, desacetyl cefotaxime. 

Ncfsse.nfj g onorriioene amoxicillin (+ probenecid) or a quiiiolone spectinomycin or cefixime or cefotaxime... 

Pharmacokinetics. Usually, cephalosporins are excreted unchanged in the urine, but some, including cefotaxime, form a desacetyl metabolite which possesses some antibacterial activity. Many are actively secreted by the renal tubule, a process which can be blocked with probenecid. As a rule, the dose of cephalosporins should be reduced in... 

Uncomplicated anogenital infections amoxicillin with probenecid by mouth spectinomycin i.v., cefotaxime i.m. or ciprofloxacin by mouth may be used for penicillin-allergic patients. 

Ceftriaxone 250 mg IM once or ciprofloxacin 500 mg p.o. once or norfloxacin 800 mg p.o. or cefuroxime axetil 1 g p.o. once plus probenecid 1 g or cefotaxime 1 g IM once or ceftizoxime 500 mg IM once plus Doxycycline 100 mg two times daily for 7 days or tetracycline 500 mg four times daily for 7 days... 

Cefotaxime Intramuscular/lntravenous Oral probenecid 500 mg every 6 hours for 24 hours before, and 1 g 30 minutes before, intravenous cefotaxime 1 g reduced renal clearance by about half and almost doubled its AUC. Delayed excretion and increased plasma levels due to effects on renal tubular transfer. Clearance of cefotaxime and also its metabolites decreased by probenecid 19-21... 

Luthy et al. (1979) studied the pharmacokinetics of cefotaxime in healthy human volunteers. Doses of 0.5, 1, and 2 g of cefotaxime were administered by intravenous infusion over 15 min. Concentrations of cefotaxime in the serum measured just after the end of the infusion were 41, 93, and 160 p.g/ml, respectively. With increasing doses, serum concentrations rose in a nonlinear fashion as the result of a decrease in total body clearance. Renal clearance of cefotaxime modestly exceeded the creatinine clearance rate, which suggests some tubular secretion. This was confirmed in studies using probenecid (Bax et al., 1980). The mean plasma half-life was 1.25 hr. Sixty percent of the administered dose was excreted in the urine. Protein binding was 30% (Neu et al., 1979a). 

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