atenolol  GENERIC NAME: atenolol BRAND NAME: Tenormin DRUG CLASS AND MECHANISM: Atenolol is a beta-adrenergic blocking agent. Atenolol 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, atenolol reduces the heart rate and is useful in treating abnormally rapid heart rhythms. Atenolol also reduces the force of heart muscle contraction and lowers blood pressure. By reducing the heart rate and the force of muscle contraction, atenolol reduces heart muscle oxygen demand. Since angina occurs when oxygen demand of the heart exceeds supply, atenolol is helpful in treating angina. PRESCRIPTION: yes GENERIC AVAILABLE: yes PREPARATIONS: Tablets: 25 mg, 50 mg, 100 mg. STORAGE: Tablets should be stored at room temperature in a tightly closed container. PRESCRIBED FOR: Atenolol is prescribed for patients with high blood pressure (hypertension). It is also used to treat chest pain (angina pectoris) related to coronary artery disease. Atenolol is also useful in slowing and regulating certain types of abnormally rapid heart rates (tachycardias). Other uses for atenolol 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: Atenolol 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), atenolol can cause dangerously slow heart rates, and even shock. Atenolol 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 atenolol. In patients with coronary artery disease, abruptly stopping atenolol can suddenly worsen angina, and occasionally precipitate heart attacks. If it is necessary to discontinue atenolol, its dosage can be reduced gradually over several weeks. Atenolol can mask the early warning symptoms of low blood sugar (hypoglycemia), and should be used with caution in patients receiving treatment for diabetes. It is not habit forming. PREGNANCY: Atenolol may cause harm and growth retardation in the fetus when given to pregnant women. SIDE EFFECTS: Atenolol is generally well tolerated, and 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, numbness, tingling, cold extremities, sore throat, and shortness of breath or wheezing.