What is the recommended amoxicillin (amoxicillin) dose for prophylaxis before a procedure?

Amoxicillin Prophylaxis Dosing for Procedures

For standard prophylaxis before dental procedures, the recommended dose of amoxicillin is 2.0 g orally administered 1 hour before the procedure for adults, and 50 mg/kg for children (not to exceed adult dose). 1, 2

Prophylaxis Regimens by Procedure Type

Dental/Oral/Respiratory Tract Procedures

• Standard regimen:

  • Adults: Amoxicillin 2.0 g orally 1 hour before procedure
  • Children: Amoxicillin 50 mg/kg orally 1 hour before procedure (not exceeding adult dose) 1, 2

• For penicillin-allergic patients:

  • Adults: Clindamycin 600 mg orally 1 hour before procedure
  • Children: Clindamycin 20 mg/kg orally 1 hour before procedure
  • Alternative options: Azithromycin or clarithromycin 500 mg (adults) or 15 mg/kg (children) orally 1 hour before procedure 1, 2

For Patients Unable to Take Oral Medications

• Adults: Ampicillin 2.0 g IM or IV within 30 minutes before procedure
• Children: Ampicillin 50 mg/kg IM or IV within 30 minutes before procedure 1

Genitourinary/Gastrointestinal Procedures

• High-risk patients:

  • Adults: Ampicillin 2.0 g IM/IV plus gentamicin 1.5 mg/kg (not exceeding 120 mg) within 30 minutes of starting procedure
  • Six hours later: Ampicillin 1 g IM/IV or amoxicillin 1 g orally
  • Children: Ampicillin 50 mg/kg IM/IV plus gentamicin 1.5 mg/kg within 30 minutes of starting procedure 1

• Moderate-risk patients:

  • Adults: Amoxicillin 2.0 g orally 1 hour before procedure or ampicillin 2.0 g IM/IV within 30 minutes of starting procedure
  • Children: Amoxicillin 50 mg/kg orally 1 hour before procedure or ampicillin 50 mg/kg IM/IV within 30 minutes of starting procedure 1

Patient Selection for Prophylaxis

Prophylaxis is recommended for high-risk cardiac patients, including those with:

• Prosthetic cardiac valves
• Previous history of infective endocarditis
• Unrepaired cyanotic congenital heart disease
• Completely repaired congenital heart disease with prosthetic material (for first 6 months after procedure)
• Cardiac transplant recipients with cardiac valvulopathy 2

Timing Considerations

The timing of antibiotic administration is critical for efficacy:

• Oral amoxicillin should be administered 30-60 minutes before the procedure 2
• IV/IM antibiotics should be administered within 30 minutes before the procedure 1
• Administration more than 120 minutes before incision or after incision is associated with a significantly higher risk of surgical site infections 3

Important Clinical Considerations

• Single dose is sufficient: Research shows that a single preoperative dose of amoxicillin (2g) is as effective as extended postoperative regimens for procedures like dental implant placement, with fewer adverse events 4

• Avoid cephalosporins in individuals with immediate-type hypersensitivity reactions to penicillins (urticaria, angioedema, or anaphylaxis) 1, 2

• Dose adequacy: Studies have confirmed that the 2.0 g dose of amoxicillin provides adequate serum levels that remain substantially higher than the MICs for oral streptococci for at least 6 hours after dosing 5

• Prophylaxis duration: For most procedures, postoperative administration is not recommended. Antibiotic prophylaxis should generally be given as a single dose 6, 7

• Oral hygiene importance: Maintaining optimal oral hygiene is more important than antibiotic prophylaxis for preventing infective endocarditis 2

The evidence strongly supports using a single 2.0 g dose of oral amoxicillin for adults (50 mg/kg for children) as the standard prophylactic regimen before procedures, with appropriate alternatives for patients with penicillin allergies or those unable to take oral medications.