Intravenous diltiazem and CYP3A-mediated metabolism

A. L. Masica, N. E. Azie, D. C. Brater, S. D. Hall, D. R. Jones

Research output: Contribution to journalArticle

10 Scopus citations


Aims: To study whether intravenous diltiazem, a calcium channel blocker commonly prescribed for hypertension and stable angina, is an inhibitor of the CYP3A enzymes by using oral lovastatin, an HMG Co-A reductase inhibitor, as a substrate. Methods: Ten healthy volunteers were studied in a randomized two-way crossover design. The two arms were 1) administration of a 20 mg dosage of lovastatin orally and 2) administration of a 20 mg dosage of lovastatin orally 1 h after an intravenous loading dosage and constant infusion of diltiazem. Blood samples were collected up to 25 h in order to quantify lovastatin and diltiazem concentrations in the separated serum. Lovastatin and diltiazem concentrations were quantified by GC-MS and h.p.l.c., respectively. Results: Intravenous diltiazem did not significantly affect the oral AUC, C(max), t( 1/2 ) or t(max) of lovastatin. Conclusions: These data suggest that the interaction of lovastatin with diltiazem does not occur systemically and is primarily a first-pass effect. Thus, drug interactions with diltiazem may become evident when a patient is moved from intravenous to oral dosing.

Original languageEnglish (US)
Pages (from-to)273-276
Number of pages4
JournalBritish Journal of Clinical Pharmacology
Issue number3
StatePublished - Sep 28 2000


  • Calcium channel blockers
  • CYP3A
  • Diltiazem
  • Drug interactions
  • Lovastatin

ASJC Scopus subject areas

  • Pharmacology (medical)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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  • Cite this

    Masica, A. L., Azie, N. E., Brater, D. C., Hall, S. D., & Jones, D. R. (2000). Intravenous diltiazem and CYP3A-mediated metabolism. British Journal of Clinical Pharmacology, 50(3), 273-276.