Summary
The influence of antituberculosis drugs on the plasma level of verapamil was studied after its oral and intravenous administration. Six patients who had been treated for at least 6 months with a combination of rifampicin, ethambutol and isoniazid received a single oral dose of 40 mg verapamil. As compared to untreated subjects, the antituberculosis drugs greatly reduced the bioavailability of the calcium antagonist. Studies in patients in whom treatment with ethambutol and isoniazid had been discontinued revealed that the effect was due to rifampicin. The drugs for tuberculosis had no influence on the plasma level of verapamil when it was given intravenously. The findings can be explained by the induction of verapamil metabolizing liver enzymes in patients treated with rifampicin.
References
Mooy J, Böhm R, van Baak M, van Kemenade J, Rahn KH (1985) Treatment with antituberculosis drugs strongly reduces the bioavailability of oral verapamil. Naunyn-Schmiedebergs Arch Pharmacol 330: R 79
Eichelbaum M, Ende M, Remberg G, Schomerus M, Dengler HJ (1979) The metabolism of DL-(14C)-verapamil in man. Drug Metab Dispos 7: 145–148
Kates RE (1983) Calcium antagonists: Pharmacokinetics properties. Drugs 25: 113–124
Baciewicz AM, Self TH (1984) Rifampicin drug interactions. Arch Intern Med 144: 1667–1671
Engelhard D, Stutman HR, Marks MI (1984) Interaction of ketoconazole with rifampicin and isoniazid. N Engl J Med 304: 1681–1683
Mooy J, Schols M, van Baak M, van Hooff M, Muytjens A, Rahn KH (1985) Pharmacokinetics of verapamil in patients with renal failure. Eur J Clin Pharmacol 28: 405–410
Zerbe GO (1979) Randomization analysis of randomized block design extended to growth and response curves. Commun Stat Theor Methodol A 8 [2]: 191–205
Wilkinson GR, Shand DG (1975) A physiological approach to hepatic drug clearance. Clin Pharmacol Ther 18: 377–390
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Mooy, J., Böhm, R., van Baak, M. et al. The influence of antituberculosis drugs on the plasma level of verapamil. Eur J Clin Pharmacol 32, 107–109 (1987). https://doi.org/10.1007/BF00609969
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DOI: https://doi.org/10.1007/BF00609969