Do NOT use Tenormin if:

• you are allergic to any ingredient in Tenormin
• you have a very slow heartbeat, heart block, uncontrolled heart failure, shock caused by serious heart problems, or low blood pressure after a heart attack
• you have an untreated adrenal gland tumor (pheochromocytoma)
• you are taking mibefradil.

Contact your doctor or health care provider right away if any of these apply to you.

Tell your health care provider if you have any medical conditions, especially if any of the following apply to you:

• if you are pregnant, planning to become pregnant, or are breast-feeding
• if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
• if you have allergies to medicines, foods, or other substances
• if you have a history of any severe allergic reaction
• if you have a history of lung or breathing problems (eg, asthma, chronic bronchitis, chronic obstructive pulmonary disease [COPD], emphysema), heart problems (eg, heart failure, conduction problems, left ventricle problems), blood vessel problems, diabetes, kidney problems, an adrenal gland tumor, or an overactive thyroid.

Some medicines may interact with Tenormin. Tell your health care provider if you are taking any of the following medicines.

• Clonidine because the risk of severe high blood pressure may be increased
• Mefloquine because the risk of irregular heartbeat may be increased
• Amiodarone, calcium channel blockers (eg, diltiazem, verapamil), catecholamine-depleting medicines (eg, reserpine), digoxin, disopyramide, flecainide, ketanserin, mibefradil, or quinidine because they may increase the risk of Tenormin's side effects
• Indomethacin or phenylpropanolamine because it may decrease Tenormin's effectiveness
• Bupivacaine, lidocaine, or quinazolines (eg, alfuzosin) because the risk of their side effects may be increased by Tenormin.

This may not be a complete list of all interactions that may occur. Ask your health care provider if Tenormin may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

Important safety information:

• Tenormin may cause dizziness or drowsiness. These effects may be worse if you take it with alcohol or certain medicines. Use Tenormin with caution. Do not drive or perform other possible unsafe tasks until you know how you react to it.
• Tenormin may cause dizziness, lightheadedness, or fainting; alcohol, hot weather, exercise, or fever may increase these effects. To prevent them, sit up or stand slowly, especially in the morning. Sit or lie down at the first sign of any of these effects.
• Tell your doctor or dentist that you take Tenormin before you receive any medical or dental care, emergency care, or surgery.
• Tenormin may reduce the amount of blood that flows to your feet and hands. This may cause them to feel cold and make you more sensitive to the cold. Dress warmly in cold weather. Be careful when you are out in the cold for long periods of time. Ask you doctor for more information.
• If you have a history of any severe allergic reaction, talk with your doctor. You may be at risk for an even more severe allergic reaction if you come into contact with the substance that caused your allergy. Some medicines used to treat severe allergies may also not work as well while you are using Tenormin.
• Patients who take medicine for high blood pressure often feel tired or run down for a few weeks after starting treatment. Be sure to take your medicine even if you may not feel "normal." Tell your doctor if you develop any new symptoms.
• Diabetes patients- Tenormin may hide signs of low blood sugar such as a rapid heartbeat. Other symptoms, such as sweating, may still occur. Check your blood sugar levels regularly. Ask your doctor before you change the dose of your diabetes medicine.
• Check your blood pressure and pulse regularly, as directed by your doctor. Ask your doctor or pharmacist for help if you are unsure how to properly measure your blood pressure or pulse.
• Lifestyle changes may also help reduce your blood pressure. Talk with your doctor about appropriate diet and exercise programs that may be helpful to you.
• Lab tests, including blood pressure and heart function tests, may be performed while you use Tenormin. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
• Use Tenormin with caution in the elderly; they may be more sensitive to its effects, especially dizziness.
• Tenormin should be used with extreme caution in children; safety and effectiveness in children have not been determined.
• Pregnancy and breast-feeding: Tenormin has been shown to cause harm to the fetus. If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Tenormin while you are pregnant. Tenormin is found in breast milk. If you are or will be breast-feeding while you use Tenormin, check with your doctor. Discuss any possible risks to your baby.

All medicines may cause side effects, but many people have no, or minor, side effects.

Check with your doctor if any of these most common side effects persist or become bothersome:

Cold fingers and toes; diarrhea; dizziness; drowsiness; nausea; tiredness or weakness.

Seek medical attention right away if any of these severe side effects occur:

Severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); blue fingernails, toenails, or palms; decreased sexual ability; fainting; mental or mood problems; persistent dizziness or lightheadedness; shortness of breath; sudden, unusual weight gain; swelling of hands, ankles, or feet; unusual bruising or bleeding; unusually slow heartbeat.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider.