Amoxicillin 850 mg BID for 10 Days
Amoxicillin 850 mg twice daily for 10 days is NOT a standard dosing regimen and should be avoided. The dose of 850 mg does not align with established guidelines or FDA-approved dosing for any indication.
Standard Amoxicillin Dosing
The FDA-approved and guideline-recommended dosing for amoxicillin depends on the specific infection:
For Group A Streptococcal Pharyngitis
- Standard adult dose: 500 mg twice daily for 10 days 1, 2
- Alternative: 250 mg four times daily for 10 days 2
- Pediatric: 50 mg/kg once daily (max 1000 mg) OR 25 mg/kg twice daily (max 500 mg) for 10 days 2
For Other Respiratory Infections
- Mild to moderate ear/nose/throat infections: 500 mg every 12 hours 3
- Severe infections or lower respiratory tract: 875 mg every 12 hours 3
For H. pylori Eradication
- Triple therapy: 1000 mg (1 gram) twice daily for 14 days 3
Why 850 mg BID Is Problematic
The 850 mg dose creates several issues:
Non-standard formulation: Amoxicillin is manufactured as 250 mg, 500 mg, 875 mg, and 1000 mg tablets 3. An 850 mg dose would require splitting tablets or combining formulations, increasing medication errors and reducing compliance.
Dosing confusion: The dose falls between the standard 500 mg BID (for mild infections) and 875 mg BID (for severe infections), creating ambiguity about infection severity and treatment intent.
No evidence base: No guidelines or clinical trials support 850 mg dosing for any indication [1-2.
Correct Approach
Choose the appropriate standard dose based on infection severity:
- For mild to moderate infections: Use 500 mg twice daily for 10 days 3
- For severe infections or when higher tissue penetration is needed: Use 875 mg twice daily for 10 days 3
Key considerations:
- The 10-day duration is appropriate for most bacterial infections, particularly streptococcal pharyngitis where it prevents acute rheumatic fever 2, 3
- Twice-daily dosing improves compliance compared to three or four times daily regimens 4, 5, 6
- Take at the start of meals to minimize gastrointestinal intolerance 3
Common pitfall: Avoid creating non-standard doses by attempting to "split the difference" between approved formulations. This increases medication errors and has no clinical benefit. Stick to FDA-approved dosing: 500 mg BID for standard coverage or 875 mg BID for enhanced coverage.