Home › Compound Library › Clarithromycin (Biaxin)

Clarithromycin (Biaxin)

Antibioticprescriptionoral · inferred

Macrolide antibiotic with broad-spectrum coverage. Highly lipophilic, achieving excellent lung and intracellular penetration. Potent mechanism-based inhibitor of CYP3A4/5 and P-glycoprotein. Causes numerous clinically significant drug interactions with CYP3A4 substrates (statins, immunosuppressants, benzodiazepines, anticoagulants). Notable for simvastatin black-box warning (rhabdomyolysis). Nonlinear PK: autoinhibits its own metabolism with repeated dosing.

Projected serum levels — 500 mg, twice daily

Clarithromycin (Biaxin)
Clarithromycin (Biaxin) modeled serum levels, 500 mg twice daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 1 days. 0 62.5 125 188 250 Day 0 Day 4 Day 7 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 1

Maintenance schedule: 500 mg twice daily (oral).

Modeled steady state after ~1 days: peak ≈ 214 mg, trough ≈ 48.6 mg body load. Population-based estimate over 15 days for a 500 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Antibiotic
Route modeled
Oral
Model confidence
inferred
Half-life
4 h
Common dose
500 mg
Suggested maximum
1k mg/day
Reference dose range
250–1k mg (single dose)
Suggested cadence
twice daily
Validated against
500 mg oral — Cmax 2.5 mg/L at 2.5 h

Documented interactions

  • contraindicated
    Alfuzosin (Uroxatral) + Clarithromycin (Biaxin) CYP inhibition

    Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Alfuzosin (Uroxatral) AUC by ~10.00x

  • contraindicated
    Alprazolam (Xanax) + Clarithromycin (Biaxin) CYP inhibition

    Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Alprazolam (Xanax) AUC by ~10.00x

  • contraindicated
    Amlodipine (Norvasc) + Clarithromycin (Biaxin) CYP inhibition

    Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Amlodipine (Norvasc) AUC by ~10.00x

  • contraindicated
    Anastrozole (Arimidex) + Clarithromycin (Biaxin) CYP inhibition

    Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Anastrozole (Arimidex) AUC by ~5.14x

  • contraindicated
    Astaxanthin + Clarithromycin (Biaxin) CYP inhibition

    Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Astaxanthin AUC by ~10.00x

  • contraindicated
    Atogepant (Qulipta) + Clarithromycin (Biaxin) CYP inhibition

    Clarithromycin (Biaxin) mechanism_based of CYP3A4 predicted to change Atogepant (Qulipta) AUC by ~10.00x

Serum checks 335 modeled interaction pairings for clarithromycin (biaxin) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. The cytochrome P4503A4 inhibitor clarithromycin increases the plasma concentrations and effects of repaglinide Niemi M et al. · Clinical Pharmacology & Therapeutics, 2001 DOI

    Clinical DDI study demonstrating clarithromycin as potent CYP3A4 inhibitor, increasing repaglinide AUC 40% and Cmax 67%.

  2. Modeling the Autoinhibition of Clarithromycin Metabolism during Repeated Oral Administration Chu X et al. · Drug Metabolism and Disposition, 2009 DOI

    PK model showing mechanism-based inhibition of CYP3A4 by clarithromycin N-demethyl metabolite; autoinhibition plateau at 48 hours.

  3. Evidence-Based Guidelines for Drug Interaction Studies: Model-Informed Time Course of Intestinal and Hepatic CYP3A4 Inhibition by Clarithromycin European Medicines Agency · European Journal of Clinical Pharmacology, 2021 DOI

    Regulatory guidance on clarithromycin CYP3A inhibition time-course for conducting drug interaction studies; 500 mg BID standard.

3 published studies referenced in the app, each with a plain-language summary.