Calan SR can help lower high blood pressure by causing the blood vessels to relax, which helps improve blood flow and makes it easier for the heart to pump blood. The prescription medication comes in the form of a tablet that is typically taken once or twice a day. Although most people have no problems with it, side effects can include constipation, dizziness, and nausea.
Calan SR is made by Pfizer, Inc. Generic versions are made by several manufacturers.
How Does the Medication Work?
Calan SR is part of a class of drugs called calcium channel blockers. It helps to slow down the rate at which calcium moves into your heart and blood vessel walls. This, in turn, helps to relax the blood vessels, which improves blood flow and makes it easier for the heart to pump blood.
There are two basic types of calcium channel blockers: dihydropyridine and non-dihydropyridine. The most important difference between the two is that non-dihydropyridine calcium channel blockers can slow down the heart rate, while dihydropyridine calcium channel blockers do not. Calan SR is a non-dihydropyridine calcium channel blocker, which means that it can decrease the heart rate. As a result, the medicine is useful for treating certain types of irregular heart rhythms (arrhythmias).
Written by/reviewed by: Kristi Monson, PharmD;Arthur Schoenstadt, MD
Last reviewed by: KristiMonson, PharmD;
List of references (click here):
Calan SR [package insert]. New York, NY: Pfizer, Inc.;2009 October.
Calan [package insert]. New York, NY: Pfizer Inc.;2011 October.
Food and Drug Administration, Center for Drug Evaluation and Research. Electronic orange book: Approved drug products with therapeutic equivalence evaluations. FDA Web site. Available at: http://www.fda.gov/cder/ob/. Accessed March 21, 2007.
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