Recommended Clarithromycin Dosage for Pneumonia
For community-acquired pneumonia, clarithromycin should be dosed at 500 mg twice daily for 7 days as immediate-release formulation, or 1000 mg (1 gram) once daily for 7 days as extended-release formulation. 1, 2
Dosing Recommendations Based on Patient Setting and Severity
Outpatient Treatment
- For healthy outpatients with community-acquired pneumonia (CAP), clarithromycin can be used as monotherapy at 500 mg twice daily or extended-release 1000 mg once daily for 7 days 1, 3
- Monotherapy with clarithromycin should only be used in areas with pneumococcal resistance to macrolides <25% 1, 3
- For outpatients with comorbidities, clarithromycin should be used as part of combination therapy with a β-lactam (not as monotherapy) 1, 3
- Recommended combination for outpatients with comorbidities: amoxicillin/clavulanate or cephalosporin PLUS clarithromycin 500 mg twice daily or extended-release 1000 mg daily 1, 3
Hospitalized Patients
- For hospitalized non-ICU patients, clarithromycin 500 mg twice daily in combination with a β-lactam (ampicillin/sulbactam, cefotaxime, ceftriaxone) is recommended 1, 4
- For severe CAP requiring ICU care, clarithromycin 500 mg twice daily IV can be used in combination with a broad-spectrum β-lactam 4
Specific Pathogen Considerations
For Atypical Pneumonia
- For Chlamydophila pneumoniae: Clarithromycin 500 mg PO twice daily for 10 days 4
- For Legionella species: Clarithromycin 500 mg PO twice daily (alternative to levofloxacin or azithromycin) 4
- For Mycoplasma pneumoniae: Clarithromycin is an alternative to doxycycline 4
Treatment Duration
- Standard treatment duration for CAP with clarithromycin is 7 days for most patients 1, 2
- Treatment should generally not exceed 8 days in a responding patient 4
- For specific pathogens like Legionella, longer courses (10-14 days) may be needed 4, 3
Special Considerations
Dosage Adjustments
- For patients with severe renal impairment (CrCl <30 mL/min): Reduce clarithromycin dosage by 50% 2
- For patients with moderate renal impairment (CrCl 30-60 mL/min) taking concomitant atazanavir or ritonavir: Reduce dosage by 50% 2
- For patients with severe renal impairment taking concomitant atazanavir or ritonavir: Reduce dosage by 75% 2
- No dosage adjustment needed for elderly patients or those with hepatic impairment 5
Administration Guidelines
- Extended-release tablets should be taken with food 2
- Extended-release tablets should be swallowed whole; do not chew, break or crush 2
Clinical Efficacy
- Clarithromycin has demonstrated similar clinical efficacy to beta-lactam antibiotics, cephalosporins, and other macrolides in the treatment of CAP 5, 6
- Clinical cure rates of approximately 90% have been reported in multiple studies 6, 7, 8
- Clarithromycin is effective against common respiratory pathogens including S. pneumoniae, H. influenzae, M. catarrhalis, and atypical pathogens 5, 9
Common Pitfalls and Caveats
- Avoid macrolide monotherapy in patients with significant risk of drug-resistant S. pneumoniae infection 1, 3
- Do not use clarithromycin if the patient has received macrolides in the previous 3 months; choose an agent from a different class 1, 3
- Be aware of potential drug interactions related to the cytochrome P450 system 5
- Clinical failure can occur with macrolide-resistant isolates, particularly in patients with risk factors 1
- For patients not improving on initial therapy, consider adding or changing to a different antibiotic class 3