What is the recommended dose of amoxicillin before dental work in a patient with a prosthetic (artificial) valve?

Amoxicillin Prophylaxis for Dental Procedures in Patients with Prosthetic Heart Valves

For patients with prosthetic cardiac valves undergoing dental procedures, administer 2 grams of amoxicillin orally as a single dose, taken 1 hour (or 30-60 minutes) before the procedure. 1, 2

Standard Dosing Regimen

• Adults: 2.0 grams of amoxicillin orally, administered 1 hour before the dental procedure 1, 2
• This single preoperative dose provides adequate serum levels that remain substantially higher than the minimum inhibitory concentrations for oral streptococci for at least 6 hours after administration 3
• No postoperative antibiotics are needed—a single pre-procedure dose is sufficient 2

Alternative Regimens for Special Circumstances

If Unable to Take Oral Medications

• Ampicillin 2.0 grams IV or IM within 30 minutes before the procedure 1, 2

If Penicillin-Allergic

• Clindamycin 600 mg orally 1 hour before the procedure 1, 2
• Alternative options include cephalexin 2.0 g, cefadroxil 2.0 g, azithromycin 500 mg, or clarithromycin 500 mg orally 1 hour before the procedure 1
• Important caveat: Cephalosporins should NOT be used in patients with immediate-type hypersensitivity reactions (urticaria, angioedema, or anaphylaxis) to penicillins 1

If Penicillin-Allergic AND Unable to Take Oral Medications

• Clindamycin 600 mg IV within 30 minutes before the procedure 1
• Alternatively, cefazolin 1.0 g IM or IV within 30 minutes (with the same caveat about immediate-type penicillin allergy) 1

Which Dental Procedures Require Prophylaxis

Antibiotic prophylaxis is indicated for procedures involving: 2

• Manipulation of gingival tissue (e.g., scaling and root planing)
• Manipulation of the periapical region of teeth (e.g., endodontic treatment)
• Perforation of oral mucosa
• Dental extractions and periodontal surgery 1

Prophylaxis is NOT required for: 2

• Routine anesthetic injections through noninfected tissue
• Taking dental radiographs
• Placement of orthodontic brackets (though initial band placement does require prophylaxis) 1

Critical Distinction: Prosthetic Heart Valve vs. Prosthetic Joint

This recommendation applies specifically to prosthetic cardiac valves, which carry high risk for infective endocarditis with devastating consequences. 2, 4 The evidence and recommendations for prosthetic joints are entirely different—current guidelines cannot recommend for or against routine prophylaxis for prosthetic joints, as the risk-benefit calculation differs substantially. 5

Common Pitfalls to Avoid

• Do not prescribe prolonged courses of antibiotics—only a single pre-procedure dose is indicated 2
• Do not administer prophylaxis for all cardiac patients—only those at highest risk (prosthetic valves, previous endocarditis, certain congenital heart diseases, cardiac transplant with valvulopathy) require prophylaxis 2
• For patients already on long-term antibiotic therapy, select an antibiotic from a different class rather than increasing the dosage of the current antibiotic 2
• For patients on anticoagulants, prefer oral administration over intramuscular injections 2
• Timing matters: Administer within the specified window (1 hour for oral, 30 minutes for IV/IM) to ensure adequate tissue concentrations during the procedure 2

Evidence Quality Note

While no randomized controlled trials demonstrate that antibiotic prophylaxis prevents endocarditis (the incidence is too low to study effectively), 6 the potential catastrophic consequences of endocarditis in high-risk patients with prosthetic valves justify prophylaxis based on expert consensus and pathophysiological reasoning. 4 The 2-gram dose has been validated to provide adequate serum levels with minimal side effects compared to higher doses. 3