Do NOT use Betapace if:

• you are allergic to any ingredient in Betapace
• you have certain heart problems (eg, severe low heart rate, uncontrolled heart failure, certain types of abnormal heartbeat rhythm), low blood potassium or magnesium levels, severe kidney problems, or a history of asthma
• you are taking cisapride, astemizole, terfenadine, mibefradil, dofetilide, or a theophylline (eg, aminophylline).

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

Some medical conditions may interact with Betapace. Tell your doctor or pharmacist 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 breathing or lung problems (eg, chronic obstructive pulmonary disorder [COPD], asthma), a decreased appetite, an overactive thyroid, kidney problems, bronchitis, diabetes, blood flow problems, a tumor on your adrenal gland, or other heart problems
• if you are scheduled for surgery.

Some medicines may interact with Betapace. Tell your health care provider if you are taking any other medicines, especially any of the following:

• Indomethacin or phenylpropanolamine because they may decrease Betapace's effectiveness
• Clonidine, diltiazem, mibefradil, nifedipine, or verapamil because the risk of side effects, such as low blood pressure or heart problems, may be increased
• Amiodarone, antiarrhythmics (eg, quinidine, propafenone), arsenic, cisapride , dofetilide, droperidol, H₁ antagonists (eg, astemizole, terfenadine), ketanserin, macrolides and ketolides (eg, erythromycin, azithromycin), mefloquine, phosphodiesterase type 5 inhibitors (eg, sildenafil), phenothiazines (eg, thioridazine), quinolones (eg, ciprofloxacin), or ziprasidone because the risk of abnormal heart rhythms may be increased
• Bupivacaine, cocaine, epinephrine, insulin, lidocaine, meglitinide antidiabetics (eg, nateglinide), nifedipine, or quinazolines (eg, prazosin) because the risk of their side effects may be increased by Betapace
• Certain stimulants (eg, albuterol, pseudoephedrine), phenformin, or theophyllines (eg, aminophylline) because their effectiveness may be decreased by Betapace.

This may not be a complete list of all interactions that may occur. Ask your health care provider if Betapace 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:

• Betapace may cause drowsiness, dizziness, or lightheadedness. These effects may be worse if you take it with alcohol or certain medicines. Use Betapace with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
• Betapace 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 Betapace before you receive any medical or dental care, emergency care, or surgery.
• Do not suddenly stop taking Betapace. Sharp chest pain, irregular heartbeat, and sometimes heart attack may occur if you suddenly stop Betapace. The risk may be greater if you have certain types of heart disease. Heart disease is common and you may not know you have it. Your doctor should slowly lower your dose over several weeks if you need to stop taking it. Limit physical activity while you are lowering your dose. If new or worsened chest pain or other heart problems occur, contact your doctor right away. You may need to start taking Betapace again.
• Lab tests, including heart function, kidney function, and blood pressure monitoring, may be performed while you use Betapace. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
• Pregnancy and breast-feeding: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Betapace while you are pregnant. Betapace is found in breast milk. Do not breastfeed while taking Betapace.

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:

Dizziness; drowsiness; headache; light-headedness; tiredness; trouble sleeping.

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

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); abnormally fast, slow, or irregular heartbeat; changes in vision; decreased appetite; excessive thirst; numbness of an arm or leg; severe or persistent nausea, vomiting, or diarrhea; severe stomach pain; sharp or crushing chest pain; sudden leg pain; sudden severe headache, vomiting, dizziness, or fainting; sudden shortness of breath; unusual sweating.

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.