For which diseases is penicillin prophylaxis given and what is its duration?

Penicillin Prophylaxis: Indications and Duration

Penicillin prophylaxis is primarily indicated for rheumatic fever prevention, prevention of recurrent cellulitis, and surgical prophylaxis for specific procedures, with duration varying based on the specific condition and risk factors. 1

Rheumatic Fever Prevention

Secondary Prevention

• Intramuscular benzathine penicillin G 1.2 million units every 4 weeks is the recommended regimen for secondary prevention of rheumatic fever in most circumstances 1
• In high-risk populations with high incidence of rheumatic fever, administration every 3 weeks may be justified 1
• Alternative oral regimens include penicillin V potassium 250 mg orally twice daily 1

Duration of Prophylaxis

• For patients with rheumatic carditis and persistent valvular disease: continue for 10 years after the last episode or until age 40, whichever is longer 1
• For patients with rheumatic carditis but no residual heart disease: continue for 10 years or until age 21, whichever is longer 1
• For patients with rheumatic fever without carditis: continue for 5 years or until age 21, whichever is longer 1
• Lifelong prophylaxis may be considered for high-risk patients with significant valvular disease 1
• Prophylaxis should continue even after valve surgery, including prosthetic valve replacement 1

Recurrent Cellulitis Prevention

• Prophylactic antibiotics should be considered in patients who have 3-4 episodes of cellulitis per year despite treatment of predisposing factors 1
• Options include:
  • Oral penicillin or erythromycin twice daily for 4-52 weeks 1
  • Intramuscular benzathine penicillin every 2-4 weeks 1
• Duration: Continue as long as predisposing factors persist 1

Surgical Prophylaxis

Orthopedic Surgery

• Joint prosthesis (upper/lower limb): Cefazolin 2g IV (pre-op), with 1g re-injection if duration >4h; limited to operative period (24 hours max) 1
• Alternative for penicillin allergy: Clindamycin 900 mg IV or vancomycin 30 mg/kg/120 min 1

Trauma Surgery

• Closed fractures requiring intrafocal osteosynthesis: Cefazolin 2g IV, limited to operative period (24 hours max) 1
• Open fractures stage I Cauchoix: Cefazolin, cefamandole, or cefuroxime, limited to operative period (24 hours max) 1
• Open fractures stage II and III Cauchoix: Antibiotic prophylaxis for maximum 48 hours 1

Finger Amputation

• Aminopenicillin plus beta-lactamase inhibitor 2g IV initially, then 1g every 6 hours for maximum 48 hours 2
• For penicillin allergy: Clindamycin 900 mg IV followed by 600 mg every 6 hours for 48 hours, plus gentamicin 2

Infective Endocarditis Prophylaxis

Native Valve Endocarditis

• For methicillin-susceptible S. aureus endocarditis: Nafcillin or oxacillin IV for 4-6 weeks 1
• Optional addition of gentamicin for first 3-5 days may accelerate bacterial killing 1

Prophylaxis for Dental Procedures

• Single high-dose amoxicillin or 2-dose phenoxymethylpenicillin for normal-risk patients 3
• For penicillin allergy: 2-dose erythromycin or single high-dose clindamycin 3
• Parenteral agents recommended for high-risk patients with prosthetic heart valves 3

Important Clinical Considerations

• Antibiotic prophylaxis should generally be brief, limited to the operative period or up to 48 hours maximum for specific cases 2
• First dose of surgical prophylaxis should be administered within 60 minutes before incision 2
• For those at high risk of developing infective endocarditis complications, there appears to be concerning underprescribing of prophylaxis for invasive dental procedures 4
• The risk of developing infective endocarditis after dental procedures is estimated to be 1 in 46,000 for unprotected procedures and 1 in 150,000 for protected procedures 5

Caveats and Pitfalls

• Prolonging antibiotic prophylaxis beyond recommended duration increases risk of antibiotic resistance without additional benefit 2
• Failure to administer initial dose before surgical incision significantly reduces prophylaxis effectiveness 2
• The presence of drainage does not justify extending prophylaxis beyond recommended duration 2
• For patients with recurrent cellulitis, addressing predisposing factors (edema, obesity, venous insufficiency, toe web abnormalities) may decrease recurrence frequency 1