Ethanol feeding does not affect the efficacy or pharmacokinetics of azithromycin, trovafloxacin, or ceftriaxone in a rat model of pneumococcal pneumonia

A rat model of ethanol feeding was used to study the effects of ethanol on antibiotic therapy of pneumococcal pneumonia. Male Sprague-Dawley rats (150 g) received a liquid diet containing 3Gc7t of total calories as ethanol. C ontrols were pair-fed a liquid diet without ethanol or received rat chow. D iets began 7 days pre- and continued postinfection. Rats were infected tran stracheally with type 3 Streptococcus pneumoniae and then treated with azit hromycin (50 mg/kg), trovafloxacin (50 mg/kg), or ceftriaxone (100 mg/kg) i njected subcutaneously twice daily for 5 days. Antibiotic levels in serum, lung cells, and lavage fluid were measured by HPLC. Ethanol- and pair-fed r ats had depressed baseline peripheral neutrophil counts but were able to ge nerate adequate numbers of peripheral and pulmonary polymorphonuclear leuko cytes early in the course of their infection. Ethanol feeding did not alter the pharmacokinetics of azithromycin, trovafloxacin, or ceftriaxone. All t hree antibiotics were equally effective in curing experimental pneumococcal pneumonia, and survival rates were similar in treated ethanol-fed and cont rol rats.