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metoprolol succinate


Mefloquine; Quinidine/Beta-Blockers

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 not process your beta-blocker correctly. Also, both medicines may have an additive effect on your heart function.

What might happen:

The effects of your beta-blocker may increase, and you may experience more toxicities that might affect your heart.

What you should do about this interaction:

If you experience slow heartbeat, weakness, fatigue, or dizziness, contact your doctor. The dose of your medicines may need to be adjusted.Your healthcare professionals (e.g. doctor or pharmacist) may already be aware of this interaction and may be monioring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.


1.Fors WJ Jr, Vanderark CR, Reynolds EW Jr. Evaluation of propranolol and quinidine in the treatment of quinidine- resistant arrhythmias. Am J Cardiol 1971 Feb;27(2):190-4.

2.Kessler KM, Humphries WC Jr, Black M, Spann JF. Quinidine pharmacokinetics in patients with cirrhosis or receiving propranolol. Am Heart J 1978 Nov; 96(5):627-35.

3.Kates RE, Blanford MF. Disposition kinetics of oral quinidine when administered concurrently with propranolol. J Clin Pharmacol 1979 Jul; 19(7):378-83.

4.Fenster P, Perrier D, Mayersohn M, Marcus FI. Kinetic evaluation of the propranolol-quinidine combination. Clin Pharmacol Ther 1980 Apr; 27(4):450-3.

5.Dinai Y, Sharir M, Naveh N, Halkin H. Bradycardia induced by interaction between quinidine and ophthalmic timolol. Ann Intern Med 1985 Dec;103(6 ( Pt 1)):890-1.

6.Leemann T, Dayer P, Meyer UA. Single-dose quinidine treatment inhibits metoprolol oxidation in extensive metabolizers. Eur J Clin Pharmacol 1986; 29(6):739-41.

7.Zhou HH, Anthony LB, Roden DM, Wood AJ. Quinidine reduces clearance of (+)-propranolol more than (-)- propranolol through marked reduction in 4-hydroxylation. Clin Pharmacol Ther 1990 Jun;47(6):686-93.

8.Lariam (mefloquine hydrochloride) US prescribing information. Roche Pharmaceuticals August, 2009.

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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