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Cardizem LA


Midazolam; Triazolam/Diltiazem; Verapamil

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:

Serious. These medicines may interact and cause very harmful effects. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.

How the interaction occurs:

If you are taking diltiazem or verapamil, your body may not properly process midazolam or triazolam.

What might happen:

Your blood levels of midazolam or triazolam may increase and cause excess drowsiness.

What you should do about this interaction:

Let your healthcare professionals (e.g. doctor or pharmacist) know that you are taking these medicines together. If you experience severe drowsiness or confusion, contact your doctor. It may be necessary to adjust the dose of your medicine or change your medicine.Your healthcare professionals (e.g. doctor or pharmacist) 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.Backman JT, Olkkola KT, Aranko K, Himberg JJ, Neuvonen PJ. Dose of midazolam should be reduced during diltiazem and verapamil treatments. Br J Clin Pharmacol 1994 Mar;37(3):221-5.

2.Kosuge K, Nishimoto M, Kimura M, Umemura K, Nakashima M, Ohashi K. Enhanced effect of triazolam with diltiazem. Br J Clin Pharmacol 1997 Apr; 43(4):367-72.

3.Varhe A, Olkkola KT, Neuvonen PJ. Diltiazem enhances the effects of triazolam by inhibiting its metabolism. Clin Pharmacol Ther 1996 Apr; 59(4):369-75.

4.Cardizem LA (diltiazem hcl extended release tablets) US prescribing information. Abbott Pharmaceuticals, Inc. March, 2015.

5.Jones DR, Gorski JC, Hamman MA, Mayhew BS, Rider S, Hall SD. Diltiazem inhibition of cytochrome P-450 3A activity is due to metabolite intermediate complex formation. J Pharmacol Exp Ther 1999 Sep; 290(3):1116-25.

6.Wang JS, Wen X, Backman JT, Taavitsainen P, Neuvonen PJ, Kivisto KT. Midazolam alpha-hydroxylation by human liver microsomes in vitro: inhibition by calcium channel blockers, itraconazole and ketoconazole. Pharmacol Toxicol 1999 Oct;85(4):157-61.

7.Wang YH, Jones DR, Hall SD. Prediction of cytochrome P450 3A inhibition by verapamil enantiomers and their metabolites. Drug Metab Dispos 2004 Feb; 32(2):259-66.

Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, expect as may be authorized by the applicable terms of use.

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.

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