A young adult patient with a history of rheumatic fever (RF) and rheumatic heart disease (RHD), experiencing arthritis, joint pain, and chest pain upon exercise, is taking penicillin G (benzylpenicillin) monthly, when should they stop taking penicillin G?

Duration of Penicillin G Prophylaxis in Rheumatic Fever with Carditis

For this patient with rheumatic fever experiencing arthritis and chest pain on exertion (indicating carditis but likely no severe residual valvular disease), penicillin G prophylaxis should continue for 10 years after the last attack OR until age 21, whichever is longer. 1, 2

Clinical Context and Diagnosis

This patient's presentation of arthritis, joint pain, and chest pain with exercise following rheumatic fever strongly suggests rheumatic fever with carditis but without severe residual heart disease. 1 The chest pain on exertion indicates cardiac involvement, but the clinical scenario does not describe severe persistent valvular disease requiring extended prophylaxis to age 40. 1, 2

Duration Guidelines Based on Cardiac Involvement

The duration of prophylaxis follows a stratified approach based on the severity of cardiac involvement:

For Carditis WITHOUT Residual Heart Disease (Most Likely This Case):

• Prophylaxis for 10 years after the last attack OR until age 21, whichever is longer 1, 2
• This applies to patients who had carditis during their acute episode but do not have persistent severe valvular disease 1

For Carditis WITH Persistent Valvular Disease:

• Prophylaxis for 10 years after the last attack OR until age 40, whichever is longer 1, 2
• This extended duration applies only when there is documented severe or persistent valvular disease 1

For Rheumatic Fever WITHOUT Carditis:

• Prophylaxis for 5 years after the last attack OR until age 21, whichever is longer 1, 2
• This shorter duration is inappropriate for this patient given the chest pain on exertion 1

Rationale for the Recommendation

• Intramuscular benzathine penicillin G is approximately 10 times more effective than oral antibiotics in preventing recurrence (0.1% vs 1% recurrence rate) 2, 3
• The monthly (every 4 weeks) regimen represents the standard approach in the United States, with every 3-week dosing reserved for high-risk populations or those with recurrence despite adherence 2, 3, 4, 5
• Moderate-certainty evidence demonstrates that antibiotic prophylaxis reduces rheumatic fever recurrence substantially (0.7% with antibiotics versus 1.7% without) 6

Critical Clinical Pitfalls

• Do not discontinue prophylaxis prematurely based solely on age without considering the 10-year duration from last attack 1, 2
• The "whichever is longer" clause is essential—if the patient's last attack was at age 15, prophylaxis must continue until age 25 (10 years), not stop at age 21 1, 2
• Adherence is the primary determinant of prophylaxis success—most failures occur in non-adherent patients 7
• For patients requiring endocarditis prophylaxis for dental procedures while on penicillin prophylaxis, use an agent other than penicillin due to likely resistance of oral α-hemolytic streptococci 7, 2

Answer to Multiple Choice Question

Based on the clinical presentation of carditis (chest pain on exertion) but without description of severe persistent valvular disease, the answer is (d) until age 21 (with the understanding that this must be at least 10 years from the last attack, whichever is longer). 1, 2