Lopressor is part of a class of drugs called beta-adrenergic blocking agents, or beta blockers for short. As the name implies, beta blockers work by blocking beta receptors in the body. Beta receptors are located in a number of places within the body, including the heart and blood vessels. These receptors are what stress hormones (such as adrenaline) attach to, and they cause certain reactions in the body, such as an increase in:
Lopressor helps to block a specific type of beta receptor called beta-1 receptors. By blocking these receptors, the medication causes the reverse effect of these stress hormones. It decreases heart rate and both systolic and diastolic blood pressure, as well as the workload of the heart. This means that the heart requires less blood and oxygen to work properly.
Lopressor is a beta-1 selective (or cardioselective) beta blocker. This means that it mostly blocks beta-1 receptors, especially at normal doses. However, it can block beta-2 receptors in the lungs to some extent, especially at higher dosages. This can lead to breathing problems, especially in people with asthma or similar conditions.
Written by/reviewed by: Kristi Monson, PharmD;Arthur Schoenstadt, MD
Last reviewed by: KristiMonson, PharmD;
List of references (click here):
Lopressor [package insert]. East Hanover, NJ: Novartis Pharmaceuticals Corporation;2009 March.
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 January 8, 2009.
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 January 9, 2008.
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