DRUG CLASS AND MECHANISM: Metoprolol is a beta-adrenergic blocking agent. Metoprolol blocks the action of the sympathetic nervous system, a portion of the involuntary nervous system. The sympathetic nervous system stimulates the pace of the heart beat. 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 heart muscle contraction and lowers blood pressure. By reducing the heart rate and the force of muscle contraction, metoprolol reduces heart muscle oxygen demand. Since angina occurs when oxygen demand of the heart exceeds supply, metoprolol is helpful in treating angina.

PREPARATIONS: Tablets: 50 mg, 100 mg, 200 mg.

STORAGE: Tablets should be stored at room temperature in a tightly closed container.

PRESCRIBED FOR: Metoprolol is prescribed for patients with high blood pressure (hypertension). It is also used to treat chest pain (angina pectoris) related to coronary artery disease. Metoprolol is also useful in slowing and regulating certain types of abnormally rapid heart rates (tachycardias). Other uses for metoprolol include the prevention of migraine headaches and the treatment of certain types of tremors (familial or hereditary essential tremors).

DOSING: Should be taken before meals or at bedtime.

DRUG INTERACTIONS: 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. Calcium channel blockers and digoxin (Lanoxin) can cause lowering of blood pressure and heart rate to dangerous levels when administered together with metoprolol. 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 can be reduced gradually over several weeks.

Metoprolol can mask the early warning symptoms of low blood sugar (hypoglycemia), and should be used with caution in patients receiving treatment for diabetes. Safe use of metoprolol in children has not been established. It is not habit forming.

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

SIDE EFFECTS: Metoprolol is generally well tolerated, side effects are mild and transient. Rare 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.

Caution! Before starting to take this medicine, it is vital that you should consult your doctor! Do not use it on your own initiative, without medical advice.