Rythmol SR is an extended-release medication given to treat certain types of heart rhythm problems. This prescription drug comes in the form of capsules that are taken twice daily, with doses about 12 hours apart. It works by regulating the electrical impulses that move through the heart muscles. Side effects may include dizziness, nausea, and taste changes.
What Is Rythmol SR?
Rythmol SR® (propafenone SR) is a prescription medication that belongs to a group of medicines known as antiarrhythmics. It is approved to prolong the symptom-free time (to delay recurrence) in certain people with an abnormal heart rhythm called atrial fibrillation (commonly referred to as "a-fib").
Rythmol SR is an extended-release medication. The active ingredient in Rythmol SR is available in a regular-release version as well -- Rythmol® (propafenone) tablets. Regular Rythmol is taken by mouth three times a day. The doses of Rythmol SR and Rythmol are not interchangeable. Therefore, if you switch from one medication to the other, you will need to take a different dose.
Rythmol SR is made by Abbott Laboratories for GlaxoSmithKline.
How Does Rythmol SR Work?
Rythmol SR belongs to a group of medications known as Class I antiarrhythmics. Class I antiarrhythmic medications block sodium channels in the heart. Rythmol SR works by slowing down the speed at which electrical impulses move through the heart, which helps stabilize the heart rhythm.
Rythmol SR is specially formulated so the medication is released slowly from the capsule over time. This allows Rythmol SR to be taken only two times a day, compared to three times a day with regular Rythmol.
Written by/reviewed by: Kristi Monson, PharmD;Arthur Schoenstadt, MD
Last reviewed by: KristiMonson, PharmD;
List of references (click here):
Rythmol SR [package insert]. Research Triangle Park, NC: GlaxoSmithKline;2013 February.
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 May 22, 2012.
Briggs GG, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation. 8th ed. Philadelphia (PA): Lippincott Williams & Wilkins;2008.
National Library of Medicine (US). Drugs and Lactation Database (LactMED). NLM Web site. Available at: http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT. Accessed May 22, 2012.
National Library of Medicine (US). Hazardous Substances Data Bank (HSDB). NLM Web site. Available at: http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB. Accessed May 22, 2012.
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