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Ciprofloxacin strongly inhibits clozapine metabolism: two case reports

E E M Brouwers1, M Söhne, S Kuipers

  • 1Department of Pharmacy and Pharmacology, Slotervaart Hospital, the Netherlands Cancer Institute, Amsterdam, the Netherlands. Elke.Brouwers@slz.nl

Clinical Drug Investigation
|December 11, 2008
PubMed

Insights

Ciprofloxacin can dangerously increase clozapine levels, potentially causing severe side effects. Monitor clozapine concentrations closely or use alternative antibiotics when these drugs are combined.

Area of Science:

  • Pharmacology
  • Clinical Toxicology

Background:

  • Clozapine is an atypical antipsychotic used for treatment-resistant schizophrenia.
  • Ciprofloxacin is a broad-spectrum fluoroquinolone antibiotic.

Observation:

  • Two patients experienced elevated clozapine plasma concentrations after receiving ciprofloxacin.
  • One patient developed rhabdomyolysis, a severe adverse effect, concurrent with high clozapine levels.

Findings:

  • Ciprofloxacin likely inhibits CYP1A2 and CYP3A4 enzymes, impairing clozapine metabolism.
  • This drug-drug interaction can lead to significantly increased clozapine levels and potential toxicity.

Implications:

  • Clinicians should exercise caution when co-prescribing ciprofloxacin and clozapine.
  • Monitoring clozapine levels or considering alternative antibiotics is recommended to prevent adverse events.

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