metoprolol, Lopressor, Toprol XL (cont.)
Omudhome Ogbru, PharmD
Omudhome Ogbru, PharmD
Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.
Medical and Pharmacy Editor:
PREPARATIONS: Tablets: 25, 50, and 100 mg. Tablets (extended release): 25, 50, 100, and 200 mg. Injection: 1 mg/ml
PREGNANCY AND BREASTFEEDING SAFETY: Safe use of metoprolol during pregnancy has not been established.
Small quantities of metoprolol are excreted in breast milk and may potentially cause adverse effects in the infant.
STORAGE: Tablets should be stored between 15 C to 30 C (59 F to 86 F). They should be protected from moisture and dispensed in tight, light-resistant containers.
DOSING: Metoprolol should be taken before meals or at bedtime.
DRUG CLASS AND MECHANISM: Metoprolol is a beta-adrenergic blocking agent that is used for treating high blood pressure, heart pain, abnormal rhythms of the heart, and some neurologic conditions. Examples of beta-adrenergic blockers include propanolol (Inderal, Inderal LA, Innopran XL), atenolol (Tenormin), and timolol (Blocadren). Metoprolol blocks the action of the sympathetic nervous system, a portion of the involuntary nervous system, by blocking beta receptors on sympathetic nerves. Since the sympathetic nervous system is responsible for increasing the rate with which the heart beats, by blocking the action of these nerves metoprolol reduces the heart rate and is useful in treating abnormally rapid heart rhythms.
Metoprolol also reduces the force of contraction of heart muscle and thereby lowers blood pressure. By reducing the heart rate and the force of muscle contraction, metoprolol reduces the need for oxygen by heart muscle. Since heart pain (angina pectoris) occurs when oxygen demand of the heart muscle exceeds the supply of oxygen, metoprolol, by reducing the demand for oxygen, is helpful in treating heart pain. The FDA approved metoprolol in August 1978.
Medically reviewed by Eni Williams, PharmD
Reference: FDA Prescribing Information
Medically Reviewed by a Doctor on 3/31/2016
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Need help identifying pills and medications?
Back to Medications Index