Calan is used for:
Treating supraventricular tachycardia, a rhythm disturbance of the heart. It is also used for controlling heart rate response to other rhythm disturbances, specifically atrial fibrillation and atrial flutter. It may also be used for other conditions as determined by your doctor.

Calan is a calcium channel blocker. It works by slowing the electrical conduction in the heart, slowing heart rate, and/or normalizing heart rhythm.

Do NOT use Calan if:
you are allergic to any ingredient in Calan
you have certain heart conditions (eg, sick sinus syndrome or second- or third-degree heart block and do not have a pacemaker) or very low blood pressure
you have atrial fibrillation or flutter and a pre-excitation syndrome (extra conduction pathway in the heart) such as Wolff-Parkinson-White syndrome (WPW) or Lown-Ganong-Levine syndrome (LGL)
you are taking dofetilide or eletriptan

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

Before using Calan :
Some medical conditions may interact with Calan . 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 heart failure or a recent heart attack with lung congestion; low blood pressure; heart problems, including a very slow heart rate, or heart valve disease
if you have kidney or liver disease, muscular dystrophy, or neurologic disease

Some MEDICINES MAY INTERACT with Calan . Tell your health care provider if you are taking any other medicines, especially any of the following:
Beta-blockers (eg, propranolol), disopyramide, ketolides (eg, telithromycin), or macrolides (eg, erythromycin) because the actions and side effects of Calan , some potentially life-threatening, may be increased
Rifampin because it may decrease Calan 's effectiveness
Aldosterone blockers (eg, spironolactone), beta-blockers (eg, propranolol), carbamazepine, digoxin, dofetilide, eletriptan, erythromycin, flecainide, HMG-CoA reductase inhibitors (eg, simvastatin), lithium, nondepolarizing muscle relaxants (eg, atracurium), quinazolines (eg, metolazone), quinidine, or theophyllines (eg, aminophylline) because the actions and side effects, some potentially life-threatening, may be increased by Calan

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

How to use Calan :
Use Calan as directed by your doctor. Check the label on the medicine for exact dosing instructions.
Calan is usually given as an injection at your doctor's office, hospital, or clinic. If you will be using Calan at home, a health care provider will teach you how to use it. Be sure you understand how to use Calan . Follow the procedures you are taught when you use a dose. Contact your health care provider if you have any questions
Do not use Calan if it contains particles, is cloudy or discolored, or if the vial is cracked or damaged.
Keep this product, as well as syringes and needles, out of the reach of children and pets. Do not reuse needles, syringes, or other materials. Ask your health care provider how to dispose of these materials after use. Follow all local rules for disposal.
If you miss a dose of Calan , take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Calan .

Important safety information:
Calan may cause dizziness. These effects may be worse if you take it with alcohol or certain medicines. Use Calan with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
Do not drink alcohol or use medicines that may cause drowsiness (eg, sleep aids, muscle relaxers) while you are using Calan ; it may add to their effects. Ask your pharmacist if you have questions about which medicines may cause drowsiness.
Calan 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.
Lab tests, including liver function, kidney function, complete blood count, ECG, and blood pressure, may be performed while you use Calan . These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
Use Calan with caution in the ELDERLY; they may be more sensitive to its effects.
Calan should not be used in CHILDREN; safety and effectiveness in children have not been confirmed.
PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Calan while you are pregnant. Calan is found in breast milk. Do not breast-feed while taking Calan .

Possible side effects of Calan :
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; fatigue; headache; lightheadedness.
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); chest pain; lightheadedness, especially upon standing; severe dizziness; shortness of breath; swelling of feet or hands; unusually fast, slow or irregular heartbeat.