Chemoprophylaxis with oral amoxycillin against bacterial endocarditis: When should second doses be administered after dentistry?

Abstract

The adequacy of serum bactericidal activity after oral amoxycillin given as prophylaxis against infective endocarditis was studied using a double blind randomised protocol in healthy volunteers having dentistry. One hour before their procedure 38 patients received 3 g amoxycillin syrup and 12 received matching placebo. Venous blood samples were drawn before and one and nine hours after dosing and serum amoxycillin concentrations determined using a standard bioassay. Samples containing amoxycillin had inhibitory titres measured against two reference isolates of viridans streptococci known to have caused infective endocarditis. The susceptibility to amoxycillin of one strain was high. © 1986, British Medical Journal Publishing Group. All rights reserved.