For this patient with a mechanical valve preparing for hernia repair surgery, antibiotic prophylaxis to prevent bacterial endocarditis is not indicated. Prophylaxis to prevent bacterial endocarditis is appropriate before certain dental procedures for patients with specific indications placing them at high risk for an adverse outcome from infective endocarditis (class IIa recommendation). These indications include previous endocarditis, a history of cardiac transplantation, a prosthetic valve, and specific forms of complex congenital heart disease. However, prophylaxis is not recommended for nondental procedures, including transesophageal echocardiography and genitourinary or gastrointestinal procedures (such as upper endoscopy, colonoscopy, or hernia repair), in the absence of active infection (class III recommendation). Dental procedures for which antibiotic prophylaxis is reasonable include those that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa. Prophylaxis is not recommended for routine dental procedures, including radiographs and orthodontics.

When antibiotic prophylaxis is indicated, it should be given as a single dose 30 to 60 minutes before the dental procedure. If the prophylactic medication is inadvertently not administered, it may be given up to 2 hours after the procedure. Options include amoxicillin, 2 g orally, or ampicillin, 2 g intravenously. For patients allergic to penicillin or amoxicillin, alternatives include clindamycin, 600 mg orally; azithromycin, 500 mg orally; or cefazolin/ceftriaxone, 1 g intramuscularly or intravenously.