Drug Name

Tenormin (Atenolol)

 Drug Uses

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

Should be taken before meals or at bedtime.

 Drug Class and Mechanism

Tenormin is a beta-adrenergic blocking agent. Tenormin 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, tenormin reduces the heart rate and is useful in treating abnormally rapid heart rhythms. Tenormin also reduces the force of heart muscle contraction and lowers blood pressure. By reducing the heart rate and the force of muscle contraction, tenormin reduces heart muscle oxygen demand. Since angina occurs when oxygen demand of the heart exceeds supply, tenormin is helpful in treating angina.

Continue to take this medicine even if you feel well. Do not miss any doses. If you miss a dose of this medicine, take as soon as you remember if it is more than 8 hours before the next dose is due. If it is less than 8 hours until your next dose, skip the missed dose and return to your normal dosing schedule. Do not take 2 doses at once.

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

 Warnings/Precautions

Tenormin 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), tenormin can cause dangerously slow heart rates, and even shock. Tenormin 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 tenormin. In patients with coronary artery disease, abruptly stopping tenormin can suddenly worsen angina, and occasionally precipitate heart attacks. If it is necessary to discontinue tenormin, its dosage can be reduced gradually over several weeks. Tenormin 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. Do not take this medicine if you have had an allergic reaction to it or are allergic to any ingredient in this product. Do not stop taking this medicine without checking with your doctor. Some conditions may become worse when the medicine is suddenly stopped. Your dose may need to be slowly lowered to avoid side effects. Keep all doctor and laboratory appointments while you are taking this medicine. Before you have any medical or dental treatments, emergency care, or surgery, tell the doctor or dentist that you are using this medicine. This medicine may cause drowsiness or dizziness. Do not drive, operate machinery, or do anything else that could be dangerous until you know how you react to this medicine. Before having any allergy tests or shots, tell your doctor that you are using this medicine. This medicine may increase your risk for a serious reaction to the allergy shot. Before taking any new medicine, either prescription or over-the-counter, check with your doctor or pharmacist. This includes any medicines used to treat colds or congestion. Caution is advised when using this medicine in the elderly because they may be more sensitive to the effects of this medicine. For women: this medicine has been shown to cause harm to the human fetus. If you plan on becoming pregnant, discuss with your doctor the benefits and risks of using this medicine during pregnancy. This medicine is excreted in breast milk. if you are or will be breast-feeding while you are using this medicine, check with your doctor or pharmacist to discuss the risks to your baby. For patients with diabetes mellitus: this medicine may mask signs of low blood sugar such as a rapid heart rate. Check blood glucose levels regularly.

 Possible Side Effects

Tenormin 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.

 More Information

If your doctor has instructed you to check your blood pressure and heart rate regularly, be sure to do so. Ask your doctor or pharmacist for help if you are unsure how to properly measure your blood pressure or pulse. There are several lifestyle changes that may also help reduce your blood pressure. Talk with your doctor about appropriate diet and exercise programs that may be helpful to you. Do not share this medicine with others for whom it was not prescribed. Do not use this medicine for other health conditions. Keep this medicine out of the reach of children. If using this medicine for an extended period of time, obtain refills before your supply runs out.