metoprolol, Lopressor, Toprol XL (cont.)

Pharmacy Author:
Medical and Pharmacy Editor:

Fluoxetine (Prozac) can increase blood lovels of metopropol by reducing breakdown of metoprolol, and increase the side effects from metoprolol.

PREGNANCY: Safe use of metoprolol during pregnancy has not been established.

NURSING MOTHERS: Small quantities of metoprolol are excreted in breast milk and may potentially cause adverse effects in the infant.

SIDE EFFECTS: Metoprolol is generally well tolerated. Side effects include abdominal cramps, diarrhea, constipation, fatigue, insomnia, nausea, depression, dreaming, memory loss, fever, impotence, lightheadedness, slow heart rate, low blood pressure, cold extremities, sore throat, and shortness of breath or wheezing. Metoprolol can aggravate breathing difficulties in patients with asthma, chronic bronchitis, or emphysema.

In patients with existing slow heart rates (bradycardias) and heart blocks (defects in the electrical conduction of the heart), metoprolol can cause dangerously slow heart rates, and even shock. Metoprolol reduces the force of heart muscle contraction and can aggravate symptoms of heart failure. In patients with coronary artery disease, abruptly stopping metoprolol can suddenly worsen angina, and occasionally precipitate heart attacks. If it is necessary to discontinue metoprolol, its dosage should be reduced gradually over several weeks.

Medically Reviewed by a Doctor on 10/21/2013


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