What are the doses of Clarithromycin and Amoxicillin?

Dosage of Clarithromycin and Amoxicillin

For standard treatment regimens, clarithromycin is dosed at 500 mg twice daily (or extended-release 1,000 mg once daily), and amoxicillin is dosed at 1,000 mg twice daily. 1, 2

Standard Dosing for Various Indications

Helicobacter pylori Infection Treatment

• Standard Triple Therapy:

  • Clarithromycin 500 mg twice daily 1
  • Amoxicillin 1,000 mg twice daily 1
  • PPI standard dose twice daily
  • Duration: 14 days 1

• Sequential Therapy (for areas with high clarithromycin resistance):

  • First 5 days: PPI standard dose twice daily + Amoxicillin 1,000 mg twice daily
  • Next 5 days: PPI standard dose twice daily + Clarithromycin 500 mg twice daily + Metronidazole 500 mg twice daily 1

Community-Acquired Pneumonia

• For healthy outpatients:

  • Clarithromycin 500 mg twice daily or clarithromycin extended-release 1,000 mg daily 1
  • Amoxicillin 1 g three times daily (as monotherapy) 1

• For outpatients with comorbidities (combination therapy):

  • Clarithromycin 500 mg twice daily or extended-release 1,000 mg once daily 1
  • Plus amoxicillin/clavulanate (various dosing options) 1

Nontuberculous Mycobacterial Diseases

• For nodular/bronchiectatic disease (intermittent therapy):

  • Clarithromycin 1,000 mg three times weekly 1

• For fibrocavitary or severe disease (daily therapy):

  • Clarithromycin 1,000 mg/day (or 500 mg twice daily) 1
  • May need dose reduction to 500 mg/day or 250 mg twice daily for patients with small body mass (≤50 kg) or older than 70 years 1

Special Dosing Considerations

Renal Impairment

• For amoxicillin in severe renal impairment: 2
  • GFR 10-30 mL/min: 500 mg or 250 mg every 12 hours
  • GFR <10 mL/min: 500 mg or 250 mg every 24 hours
  • Patients with GFR <30 mL/min should NOT receive the 875 mg dose

Pediatric Dosing

• Amoxicillin for pediatric patients >3 months: 20-45 mg/kg/day in divided doses every 8-12 hours 2
• Amoxicillin for infants ≤3 months: Maximum 30 mg/kg/day divided every 12 hours 2

Administration Tips

• Amoxicillin should be taken at the start of a meal to minimize gastrointestinal intolerance 2
• Clarithromycin immediate-release may need to be split into twice-daily dosing due to gastrointestinal intolerance 1, 3
• Clarithromycin extended-release formulation (1,000 mg once daily) may improve compliance and gastrointestinal tolerability compared to immediate-release formulation 3

Common Pitfalls and Caveats

• For H. pylori treatment, standard triple therapy should be started after 72-96 hours of intravenous PPI administration in patients with bleeding peptic ulcer 1
• Clarithromycin can increase concentrations of drugs metabolized by CYP3A, which may be clinically significant for medications with narrow therapeutic indices 4
• For patients with nodular/bronchiectatic MAC disease, gradual introduction of medications (one at a time at 1-2 week intervals) may improve tolerance 1
• Clarithromycin has an active metabolite (14-hydroxyclarithromycin) which contributes to its antimicrobial activity, particularly against H. influenzae 4, 5