Why is Calan prescribed?
Verapamil-based medications can be prescribed for several heart and blood pressure problems. The fast-acting brands (Calan and Isoptin) are taken for angina (chest pain due to clogged cardiac arteries), as well as irregular heartbeat and high blood pressure. The longer-acting brands (Calan SR, Isoptin SR, Verelan, and Verelan PM) are typically used only for high blood pressure. Covera-HS is prescribed for both high blood pressure and angina.
Verapamil is a type of medication called a calcium channel blocker. It eases the heart's workload by slowing down the passage of nerve impulses through it, and hence the contractions of the heart muscle. This improves blood flow through the heart and throughout the body, reduces blood pressure, corrects irregular heartbeat, and helps prevent angina pain.
Some doctors also prescribe verapamil to prevent migraine headache and asthma and to treat manic depression and panic attacks.
Most important fact about Calan
If you have high blood pressure, you must take verapamil regularly for it to be effective. Since blood pressure declines gradually, it may be several weeks before you get the full benefit of verapamil; and you must continue taking it even if you are feeling well. Verapamil does not cure high blood pressure; it merely keeps it under control.
How should you take Calan?
Calan, Isoptin, and Verelan can be taken with or without food. Calan SR and Isoptin SR should be taken with food.
Covera-HS, Calan SR, Isoptin SR, Verelan and Verelan PM must be swallowed whole and should not be crushed, broken, or chewed.
You may open Verelan capsules and sprinkle the pellets on a spoonful of cool applesauce. Swallow all of the mixture immediately, and then drink a glass of cool water.
Take Calan exactly as prescribed, even if you are feeling well. Try not to miss any doses. If the drug is not taken regularly, your condition can get worse.
Check with your doctor before you stop taking Calan; a slow reduction in the dose may be required.
--If you miss a dose...
Take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Never take 2 doses at the same time.
--Storage instructions...
Store at room temperature away from heat, light, and moisture.
What side effects may occur?
Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking verapamil.
• More common side effects may include:
Congestive heart failure, constipation, dizziness, fatigue, fluid retention, headache, low blood pressure, nausea, rash, shortness of breath, slow heartbeat, upper respiratory infection
Why should Calan not be prescribed?
If you have low blood pressure or certain types of heart disease or heartbeat irregularities, you should not take verapamil. Make sure the doctor is aware of any cardiac problems you may have.
If you are sensitive to or have ever had an allergic reaction to Calan or any other brands of verapamil, or other calcium channel blockers, do not take Calan.
Special warnings about Calan
Verapamil can reduce or eliminate angina pain caused by exertion or exercise. Be sure to discuss with your doctor how much exertion is safe for you.
Verapamil may cause your blood pressure to become too low. If you experience dizziness or light-headedness, notify your doctor.
Congestive heart failure and fluid in the lungs have occurred in people taking verapamil together with other heart drugs known as beta blockers. Make sure your doctor is aware of all medications you are taking.
If you have a heart condition, liver disease, kidney disease, myasthenia gravis, or Duchenne's dystrophy (the most common type of muscular dystrophy), make certain your doctor knows about it. Verapamil should be used with caution.
If you are taking Covera-HS and you have a narrowing in your stomach or intestines, be sure your doctor was aware of it when the drug was prescribed.
The outer shell of Covera-HS does not dissolve; do not worry if you see it in your stool.
Possible food and drug interactions when taking Calan
If verapamil is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining verapamil with the following:

ACE inhibitor-type blood pressure drugs such as Capoten and Vasotec
Beta-blocker-type blood pressure drugs such as Lopressor, Tenormin, and Inderal
Vasodilator-type blood pressure drugs such as Loniten
Other high blood pressure drugs such as Minipress
Alcohol
Aspirin
Amiodarone (Cordarone)
Carbamazepine (Tegretol)
Chloroquine (Aralen)
Cimetidine (Tagamet)
Cyclosporine (Sandimmune, Neoral)
Dantrolene (Dantrium)
Digitalis (Lanoxin)
Disopyramide (Norpace)
Diuretics such as Lasix and HydroDIURIL
Erythromycin (E.E.S., Ery-Tab, PCE)
Flecainide (Tambocor)
Glipizide (Glucotrol)
Grapefruit juice
Imipramine (Tofranil)
Lithium (Lithonate)
Nitrates such as Transderm Nitro and Isordil
Phenobarbital
Phenytoin (Dilantin)
Quinidine (Quinidex)
Rifampin (Rifadin)
Ritonavir (Kaletra, Norvir)
Theophylline (Theo-Dur)
Special information if you are pregnant or breastfeeding
The effects of verapamil during pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, inform your doctor immediately. The drug appears in breast milk and could affect a nursing infant. If Calan is essential to your health, your doctor may advise you to discontinue breastfeeding until your treatment is finished.
Recommended dosage
FOR CALAN AND ISOPTIN
Dosages of Calan must be adjusted to meet individual needs. In general, dosages of Calan should not exceed 480 milligrams per day. Your doctor will closely monitor your response to Calan, usually within 8 hours of the first dose.
Safety and effectiveness of Calan in children have not been established.
Angina
The usual initial dose is 80 to 120 milligrams, 3 times a day. Lower doses of 40 milligrams 3 times a day may be used by people who have a stronger response to Calan, such as the elderly or those with decreased liver function. The dosage may be increased by your doctor either daily or weekly until the desired response is seen.
Irregular Heartbeat
The usual dose in people who are also on digitalis ranges from 240 to 320 milligrams per day divided into 3 or 4 doses.
In those not on digitalis, doses range from a total of 240 to 480 milligrams per day divided into 3 or 4 doses.
Maximum effects of Calan should be seen in the first 48 hours of use.
High Blood Pressure
Effects of Calan on blood pressure should be seen within the first week of use. Any adjustment of Calan to a higher dose will be based on its effectiveness as determined by your doctor.
The usual dose of Calan, when used alone for high blood pressure, is 80 milligrams, 3 times per day. Total daily doses of 360 milligrams and 480 milligrams may be used. Smaller doses of 40 milligrams 3 times per day may be taken by smaller individuals and the elderly.
FOR CALAN SR, ISOPTIN SR, AND VERELAN
Dosages for high blood pressure should be adjusted to meet each individual's needs.
Adults
The usual starting dose of Calan SR and Isoptin SR is 180 milligrams taken in the morning. For Verelan, it is 240 milligrams. A lower starting dose of 120 milligrams may be taken if the person is smaller. Your doctor will monitor your response to Calan and may adjust it each week. In addition, your doctor may increase the dose and add evening doses to the morning dose, based on the effectiveness of the drug.
You should see results from the drug within a week.
Children
The safety and effectiveness of Calan in children under age 18 have not been established.
Older Adults
Your doctor may start you at a lower dose of 120 milligrams and then adjust it according to your response.
FOR COVERA-HS AND VERELAN PM
Adults
For use only at bedtime, these delayed-action forms of verapamil are timed to deliver their peak benefits in the morning, when blood pressure tends to spike. The usual starting dose is 180 milligrams of Covera-HS or 200 milligrams of Verelan PM. Your doctor may raise the dose gradually if you need more.
Children
Safety and effectiveness in children under age 18 have not been established.
Older Adults
If you have poor kidneys, the dosage may need to be lowered.
Overdosage
Any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical attention immediately.
An overdose of Calan can cause fluid buildup in the lungs, kidney problems, seizures, dangerously low blood pressure, and life-threatening heart problems such as a slow or irregular heartbeat.
After treatment for an overdose, you should remain under observation in the hospital for at least 48 hours, especially if you have taken the sustained-release form of the drug.