Elevation of plasma carbamazepine concentrations by ketoconazole in patients with epilepsy

Edoardo Spina, Domenico Arena, Marie Gabriella Scordo, Antonino Fazio, Francesco Pisani, Emilio Perucca

Research output: Contribution to journalArticlepeer-review


The effect of ketoconazole (200 mg/d orally for 10 days) on the plasma concentrations of carbamazepine (CBZ) and its active metabolite carbamazepine-10,11-epoxide (CBZ-E) was assessed in eight patients with epilepsy stabilized on CBZ therapy. Administration of ketoconazole was associated with a significant increase in plasma CBZ concentrations (from 5.6 ± 1.9 to 7.2 ± 2.9 μg/ml on day 10 [means ± SD, P <0.02]), whereas plasma concentrations of CBZ-E were unchanged. After ketoconazole was discontinued, plasma CBZ levels decreased to pretreatment values. This interaction was probably mediated by an inhibiting action of ketoconazole on cytochrome CYP3A4, the main enzyme responsible for CBZ metabolism.

Original languageEnglish
Pages (from-to)535-538
Number of pages4
JournalTherapeutic Drug Monitoring
Issue number5
Publication statusPublished - Oct 1997


  • Carbamazepine
  • Carbamazepine-10,11-epoxide
  • CYP3A4
  • Drug interaction
  • Ketoconazole

ASJC Scopus subject areas

  • Toxicology
  • Health, Toxicology and Mutagenesis
  • Pharmacology
  • Biochemistry
  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology (medical)
  • Public Health, Environmental and Occupational Health


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