SUMMARY
Metoprolol is a cardioselective β1-adrenergic blocking agent used for acute myocardial infarction (MI), heart failure, angina pectoris and mild to moderate hypertension. It may also be used for supraventricular and tachyarrhythmias and prophylaxis for migraine headaches.
Mode of Action
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.

Indication
For the management of acute myocardial infarction, angina pectoris, heart failure and mild to moderate hypertension. May be used to treat supraventricular and tachyarrhythmias and as prophylaxis for migraine headaches.
Children: Not recommended.

Side Effect
Abdominal cramps, diarrhea, constipation, fatigue, insomnia, nausea, depression, dreaming, memory loss, fever, impotence, light headedness, slow heart rate, low blood pressure, cold extremities, sore throat, and shortness of breath or wheezing.

Contraindications
Patients with sinus bradycardia, AV block greater than first degree, cardiogenic shock and decompensated heart failure.
Not to be used in cases of myocardial infarction enrolled with bradycardia, systolic blood pressure less than 100 mmHg, or patients with heart failure