What is the recommended dosage and treatment regimen for Clarithromycin (Biaxin) in adults?

Clarithromycin Dosage and Treatment Regimen for Adults

For adults, the standard clarithromycin dosage is 1 gram per day in two divided doses (500 mg twice daily) for 7-14 days, with the duration depending on the specific infection being treated. 1

Standard Dosing Guidelines

The FDA-approved dosing regimen for clarithromycin extended-release tablets in adults is:

• Acute bacterial exacerbation of chronic bronchitis: 1 gram once daily for 7 days 1
• Acute maxillary sinusitis: 1 gram once daily for 14 days 1
• Community-acquired pneumonia: 1 gram once daily for 7 days 1

For immediate-release formulations, the dosing is typically:

• 250-500 mg twice daily (total 500-1000 mg daily) for 7-14 days depending on the infection 2

Specific Infection Protocols

For Pertussis (Whooping Cough)

• 1 gram per day in two divided doses (500 mg twice daily) for 7 days 2

For H. pylori Eradication

• Part of standard triple therapy: 500 mg twice daily (with PPI + amoxicillin) for 14 days 3
• The 14-day regimen is superior to 7-day regimens, with cure rates of approximately 95% versus 86% in susceptible populations 2

For Nontuberculous Mycobacterial Infections

• For serious skin, soft tissue, and bone infections caused by M. abscessus: 1000 mg/day or azithromycin 250 mg/day combined with parenteral medications (amikacin, cefoxitin, or imipenem) 2
• For pulmonary disease: typically part of a multi-drug regimen for at least 4-6 months 2

Dosage Adjustments

Renal Impairment

• Severe renal impairment (CrCl <30 mL/min): Reduce dosage by 50% 1
• Moderate renal impairment (CrCl 30-60 mL/min) with concomitant atazanavir or ritonavir: Reduce dosage by 50% 1
• Severe renal impairment with concomitant atazanavir or ritonavir: Reduce dosage by 75% 1

Administration Guidelines

• Clarithromycin extended-release tablets should be taken with food 1
• Tablets should be swallowed whole; do not chew, break, or crush extended-release tablets 1

Important Precautions and Contraindications

Contraindications

• Hypersensitivity to clarithromycin or any macrolide antibiotic 1
• Concomitant use with cisapride, pimozide, lomitapide, lovastatin, simvastatin, ergot alkaloids, or lurasidone 1
• History of cholestatic jaundice/hepatic dysfunction with prior clarithromycin use 1
• Colchicine in patients with renal or hepatic impairment 1

Drug Interactions

• Clarithromycin inhibits the cytochrome P450 enzyme system (CYP3A), which can lead to increased concentrations of drugs metabolized by this pathway 2
• Significant interactions with astemizole, cisapride, pimazole, terfenadine, and many other medications 2
• Reduce clarithromycin dose by 50% when co-administered with atazanavir 1

Common Adverse Effects

• Gastrointestinal: epigastric distress, abdominal cramps, nausea, vomiting, diarrhea 2
• Less common: hypersensitivity reactions, hepatotoxicity 2

Antimicrobial Stewardship Considerations

• Clarithromycin resistance should be considered when selecting therapy, particularly for H. pylori infections 2
• When resistance to clarithromycin exceeds 15-20%, alternative regimens should be considered 2
• For H. pylori treatment, culture-guided therapy can increase eradication rates from 72% to 94% compared to empiric therapy 4

Special Populations

• Pregnancy: FDA Pregnancy Category C - use only when benefits outweigh risks 2
• Infants <1 month: Not recommended due to potential risk similar to erythromycin-associated infantile hypertrophic pyloric stenosis 2
• Elderly: No dosage adjustment needed for normal renal function, but increased risk of torsades de pointes 1

By following these evidence-based dosing guidelines and considering patient-specific factors, clarithromycin can be effectively and safely used to treat various bacterial infections in adults.