Rifampin/Barbiturates Interactions

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.

Medical warning:

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 barbiturates each speed up how quickly your body processes the other agent.

What might happen:

One or both of your medications may not work as well.

What you should do about this interaction:

Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. Your doctor may want to check the amount of each medicine in your blood or change 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.Zilly W, Breimer DD, Richter E. Induction of drug metabolism in man after rifampicin treatment measured by increased hexobarbital and tolbutamide clearance. Eur J Clin Pharmacol 1975 Dec 19;9(2-3):219-27.
  • 2.Zilly W, Breimer DD, Richter E. Stimulation of drug metabolism by rifampicin in patients with cirrhosis or cholestasis measured by increased hexobarbital and tolbutamide clearance. Eur J Clin Pharmacol 1977 Apr 20; 11(4):287-93.
  • 3.Breimer DD, Zilly W, Richter E. Influence of rifampicin on drug metabolism: differences between hexobarbital and antipyrine. Clin Pharmacol Ther 1977 Apr;21(4):470-81.
  • 4.Rautlin de la Roy Y DE, Beauchant G, Breuil K, Patte F. Reduction of the blood level of rifampicin by phenobarbital. Presse Med 1971 Feb 13; 79(8):350.
  • 5.Acocella G, Bonollo L, Mainardi M, Margaroli P, Nicolis FB. Kinetic studies on rifampicin. III. Effect of phenobarbital on the half-life of the antibiotic. Tijdschr Gastroenterol 1974;17(3):151-8.

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CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.