This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.
Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Rifampin and phenobarbital may speed up how quickly your liver processes your benzodiazepine.Phenobarbital and a benzodiazepine, especially when you first start them, may cause sedation or suppress your natural urge to breathe.
What might happen:
Over time, your benzodiazepine might not work as well.
What you should do about this interaction:
Make sure your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together or if you have taken rifampin or phenobarbital in the previous two weeks. Let your doctor know if your medicine does not seem to be working as well, or if you might be having side effects such as sedation, confusion, feeling dizzy or uncoordinated. Your doctor may need to adjust the dose of your medicine.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Gashaw I, Kirchheiner J, Goldammer M, Bauer S, Seidemann J, Zoller K, Mrozikiewicz PM, Roots I, Brockmoller J. Cytochrome p450 3A4 messenger ribonucleic acid induction by rifampin in human peripheral blood mononuclear cells: correlation with alprazolam pharmacokinetics. Clin Pharmacol Ther 2003 Nov;74(5):448-57.
2.Schmider J, Brockmoller J, Arold G, Bauer S, Roots I. Simultaneous assessment of CYP3A4 and CYP1A2 activity in vivo with alprazolam and caffeine. Pharmacogenetics 1999 Dec;9(6):725-34.
3.Ujiie Y, Fukasawa T, Yasui-Furukori N, Suzuki A, Tateishi T, Otani K. Rifampicin markedly decreases plasma concentration and hypnotic effect of brotizolam. Ther Drug Monit 2006 Jun;28(3):299-302.
4.Ohnhaus EE, Brockmeyer N, Dylewicz P, Habicht H. The effect of antipyrine and rifampin on the metabolism of diazepam. Clin Pharmacol Ther 1987 Aug; 42(2):148-56.
5.Reinach B, de Sousa G, Dostert P, Ings R, Gugenheim J, Rahmani R. Comparative effects of rifabutin and rifampicin on cytochromes P450 and UDP-glucuronosyl-transferases expression in fresh and cryopreserved human hepatocytes. Chem Biol Interact 1999 Jun 1;121(1):37-48.
6.Chung JY, Cho JY, Yu KS, Kim JR, Jung HR, Lim KS, Jang IJ, Shin SG. Effect of the UGT2B15 genotype on the pharmacokinetics, pharmacodynamics, and drug interactions of intravenous lorazepam in healthy volunteers. Clin Pharmacol Ther 2005 Jun;77(6):486-94.
7.Chung E, Nafziger AN, Kazierad DJ, Bertino JS Jr. Comparison of midazolam and simvastatin as cytochrome P450 3A probes. Clin Pharmacol Ther 2006 Apr;79(4):350-61.
8.Floyd MD, Gervasini G, Masica AL, Mayo G, George AL Jr, Bhat K, Kim RB, Wilkinson GR. Genotype-phenotype associations for common CYP3A4 and CYP3A5 variants in the basal and induced metabolism of midazolam in European- and African-American men and women. Pharmacogenetics 2003 Oct;13(10):595-606.
9.Eeckhoudt SL, Desager JP, Robert AR, Leclercq I, Verbeeck RK, Horsmans Y. Midazolam and cortisol metabolism before and after CYP3A induction in humans. Int J Clin Pharmacol Ther 2001 Jul;39(7):293-9.
10.Backman JT, Kivisto KT, Olkkola KT, Neuvonen PJ. The area under the plasma concentration-time curve for oral midazolam is 400-fold larger during treatment with itraconazole than with rifampicin. Eur J Clin Pharmacol 1998 Mar;54(1):53-8.
11.Backman JT, Olkkola KT, Neuvonen PJ. Rifampin drastically reduces plasma concentrations and effects of oral midazolam. Clin Pharmacol Ther 1996 Jan;59(1):7-13.
12.Brockmeyer NH, Mertins L, Klimek K, Goos M, Ohnhaus EE. Comparative effects of rifampin and/or probenecid on the pharmacokinetics of temazepam and nitrazepam. Int J Clin Pharmacol Ther Toxicol 1990 Sep; 28(9):387-93.
13.Villikka K, Kivisto KT, Backman JT, Olkkola KT, Neuvonen PJ. Triazolam is ineffective in patients taking rifampin. Clin Pharmacol Ther 1997 Jan; 61(1):8-14.
14.Pentikis HS, Connolly M, Trapnell CB, Forbes WP, Bettenhausen DK. The effect of multiple-dose, oral rifaximin on the pharmacokinetics of intravenous and oral midazolam in healthy volunteers. Pharmacotherapy 2007 Oct;27(10):1361-9.
15.Anderson Gail D. Chapter 42: Pharmacokinetics and Drug Interactions. In: Wyllie's Treatment of Epilepsy: Principles and Practice, 5th Ed. 2011.
16.This information is based on or an extract from the UW Metabolism and Transport Drug Interaction Database (DIDB) Platform, Copyright University of Washington 1999-2014..