What is the recommended dosing of penicillin (Penicillin V) for a patient with tonsillitis and an ulcer?

Penicillin Dosing for Tonsillitis

For tonsillitis caused by Group A Streptococcus, penicillin V should be dosed at 250 mg orally 2-3 times daily (or 500 mg twice daily) for adults and adolescents, or 250 mg twice daily for children, for a full 10-day course. 1

Standard Dosing Regimens

Adults and Adolescents

• Penicillin V 500 mg orally twice daily for 10 days is the recommended regimen for streptococcal pharyngitis/tonsillitis 1
• Alternative dosing: 250 mg four times daily for 10 days is equally effective but less convenient 1, 2
• The FDA label specifies 125-250 mg every 6-8 hours for mild to moderately severe streptococcal infections of the upper respiratory tract 2

Children

• 250 mg orally twice daily for 10 days is recommended for most children 1
• Alternative: 250 mg three times daily for 10 days 1
• Penicillin V is preferred over penicillin G because it is more resistant to gastric acid 1

Critical Treatment Duration

• The full 10-day course is essential to achieve maximal pharyngeal eradication of Group A Streptococcus and prevent acute rheumatic fever 1
• Therapy can be safely started up to 9 days after symptom onset and still prevent rheumatic fever 1
• Twice-daily dosing has equivalent efficacy to more frequent dosing schedules and improves compliance 3

Important Considerations Regarding the Ulcer

The presence of a peptic ulcer does NOT contraindicate penicillin use or require dose adjustment. Penicillin V has no significant gastric toxicity and is safe in patients with peptic ulcer disease. However, if the patient is taking NSAIDs for symptom relief, these should be used cautiously or avoided in favor of acetaminophen due to the ulcer 1.

H. pylori Considerations

• If the ulcer is active and H. pylori-positive, standard triple therapy (amoxicillin 1000 mg twice daily, clarithromycin 500 mg twice daily, and PPI twice daily for 14 days) should be initiated after 72-96 hours of IV PPI 1
• The penicillin V for tonsillitis and amoxicillin for H. pylori eradication are different penicillins with different dosing schedules and should not be confused 1

Why Penicillin Remains First-Line

• No penicillin resistance has ever been documented in Group A Streptococcus anywhere in the world 1
• Penicillin has proven efficacy in preventing acute rheumatic fever, narrow spectrum of activity, excellent safety profile, and low cost 1
• Intramuscular benzathine penicillin G is the only antimicrobial therapy investigated in controlled studies that demonstrated prevention of initial attacks of acute rheumatic fever 1

Common Pitfalls to Avoid

• Do not shorten the course below 10 days even if symptoms resolve quickly—this dramatically increases treatment failure and rheumatic fever risk 1
• Do not delay treatment to wait for culture results if rapid antigen testing is positive—early treatment reduces morbidity and infectivity 1
• Do not prescribe once-daily penicillin V—this dosing is associated with 12 percentage points lower cure rates compared to more frequent dosing 3
• Do not avoid penicillin due to the ulcer—penicillin has no contraindication in peptic ulcer disease and does not require dose adjustment 2