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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:

When these two medicines are taken together, your body may process the narcotic pain medicine more slowly.

What might happen:

The effects of your pain medicine may increase and cause increased drowsiness, slowed breathing, and a decrease in blood pressure.

What you should do about this interaction:

If you experience excessive drowsiness, slowed breathing, weakness, fatigue, or dizziness, contact your doctor. It may be necessary to monitor your blood pressure and breathing rate. Your doctor may need to adjust the dose of your pain 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.


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9.Keeri-Szanto M. The mode of action of promethazine in potentiating narcotic drugs. Br J Anaesth 1974 Dec;46(12):918-24.

10.Reier CE, Johnstone RE. Respiratory depression: narcotic versus narcotic-tranquilizer combinations. Anesth Analg 1970 Jan-Feb; 49(1):119-24.

11.McGee JL, Alexander MR. Phenothiazine analgesia--fact or fantasy?. Am J Hosp Pharm 1979 May;36(5):633-40.

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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