ORAL AMOXICILLIN AS PROPHYLAXIS FOR ENDOCARDITIS - WHAT IS THE OPTIMAL DOSE

We compared serum levels and tolerability of oral amoxicillin in 30 he althy adults who each received 2.0 g of amoxicillin and, 1 week later, 3.0 g of the same preparation. Serum levels of amoxicillin were deter mined at 1, 2, 4, and 6 hours following its ingestion. Mean serum leve ls of amoxicillin were significantly higher after 3.0-g doses than aft er 2.0-g doses. Levels in females were higher than in males; this was a reflection of differences in body weights. Food intake had no effect on serum levels. The 2.0-g doses resulted in adequate serum levels; 6 hours after dosing, levels were still substantially higher than the M ICs for oral streptococci. Three individuals (10%) experienced mild ga strointestinal side effects after they received the 3.0-g doses; no si de effects were noted after the 2.0-g doses. We propose that to preven t bacterial endocarditis in adults who are at risk, a single 2.0-g dos e of oral amoxicillin may be adequate prophylaxis for dental, oral, or upper respiratory tract procedures.