What is the recommended dose of amoxicillin for an adult or child with no history of allergies to penicillins (PCN) and normal renal function, undergoing a dental procedure to prevent infective endocarditis?

Amoxicillin Dosing for Dental Procedure Prophylaxis

For adults without penicillin allergy and normal renal function, take 2 grams of amoxicillin orally as a single dose, 30-60 minutes (ideally 1 hour) before the dental procedure. 1, 2, 3

Adult Dosing

• Standard regimen: Amoxicillin 2 grams orally, single dose, administered 30-60 minutes before the procedure 1, 2, 3
• This is the recommendation from the American Heart Association and European Society of Cardiology for endocarditis prophylaxis 2, 3
• No post-procedure antibiotics are needed—only a single pre-procedure dose is indicated 2, 4, 3

Pediatric Dosing

• Children: 50 mg/kg orally as a single dose, 30-60 minutes before the procedure 1, 2
• Maximum pediatric dose should not exceed the adult dose of 2 grams 1

Critical Timing Considerations

• Optimal timing is 1 hour before the procedure, though 30-60 minutes is acceptable 1, 2, 3
• The timing allows for adequate serum levels that remain substantially higher than the minimum inhibitory concentrations for oral streptococci for at least 6 hours 5

Important Clinical Context

This prophylaxis is ONLY indicated for patients at highest risk of infective endocarditis, including those with: 2, 4, 3

• Prosthetic cardiac valves or prosthetic material used for cardiac valve repair
• Previous history of infective endocarditis
• Specific congenital heart diseases (unrepaired cyanotic CHD, completely repaired CHD with prosthetic material during first 6 months)
• Cardiac transplant recipients with cardiac valvulopathy

Most patients do NOT require antibiotic prophylaxis for dental procedures. Patients with mitral valve prolapse, rheumatic heart disease without prosthetic valves, and healthy individuals without cardiac risk factors do not need prophylaxis. 4, 3

Alternative Regimens for Penicillin Allergy

If the patient has a penicillin allergy:

• Clindamycin 600 mg orally, single dose, 30-60 minutes before procedure 1, 2, 3
• Cephalexin 2 grams orally can be used ONLY if there is no history of anaphylaxis, angioedema, or urticaria with penicillin 1, 2, 3
• Azithromycin or clarithromycin 500 mg orally are additional alternatives 3

Special Situations

If unable to take oral medications:

• Ampicillin 2 grams IM or IV within 30 minutes before the procedure 1, 3

If already on chronic antibiotic therapy:

• Select an antibiotic from a different class rather than increasing the current antibiotic dose 2, 4, 3
• If already on long-term penicillin, use clindamycin, azithromycin, or clarithromycin instead 2

If on anticoagulation:

• Use oral regimens and avoid intramuscular injections entirely 2, 4

If on hemodialysis with normal renal function:

• The standard 2 gram amoxicillin dose remains appropriate 2

Common Pitfalls to Avoid

• Do not prescribe prolonged courses of antibiotics—only a single pre-procedure dose is needed 2, 4, 3
• Do not prescribe prophylaxis for all dental patients—only those with highest-risk cardiac conditions require it 4, 3
• Do not use cephalosporins in patients with immediate-type penicillin hypersensitivity (anaphylaxis, angioedema, urticaria) 1, 3
• Do not give intramuscular injections to anticoagulated patients 2, 4

Evidence Quality Note

While the 2 gram dose is firmly established in guidelines from the American Heart Association and European Society of Cardiology 1, 2, 3, it's important to note that actual evidence from randomized controlled trials demonstrating that antibiotic prophylaxis prevents endocarditis is lacking—one case-control study found no significant effect 6. However, given the high mortality rate of infective endocarditis and the low risk of a single antibiotic dose, current guidelines continue to recommend prophylaxis for highest-risk patients 2, 3, 7.