[Prevention of endocarditis using amoxycillin, clindamycin or erythromycin. Pharmacokinetic observations]

Current recommendations for antibiotic prophylaxis of bacterial endocarditis include oral amoxycillin, and erythromycin or clindamycin for the penicillin-allergic patient. The authors report the serum concentrations and side effects which may be expected after the recommended oral doses of these compounds. Single doses of 3 g amoxycillin and 600 mg clindamycin, and two doses of erythromycin (1.5 g and 0.5 g 6 h apart) were administered in a random sequence to each of 12 volunteers. After administration, peak serum concentrations of amoxycillin and clindamycin were 27 mg/l and 5.5 mg/l respectively. Amoxycillin was eliminated more rapidly than clindamycin. Serum concentrations of erythromycin were below the sensitivity limit of the assay (0.03 mg/l) in 3 volunteers at 1 h and in 2 at 2 h. The mean peak serum concentrations was 3.1 mg/l. Peak levels were associated with gastrointestinal side effects such as nausea, abdominal cramps and vomiting. The implications of these findings are discussed with respect to use of these antibiotics for the prophylaxis of bacterial endocarditis.