Verapamil (patient information)
Why this medication is prescribed
Verapamil is used to treat irregular heartbeats (arrhythmias) and high blood pressure. It relaxes your blood vessels so your heart does not have to pump as hard. It also increases the supply of blood and oxygen to the heart to control chest pain (angina). If taken regularly, verapamil controls chest pain, but it does not stop chest pain once it starts. Your doctor may give you a different medication to take when you have chest pain.
This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.
How this medication should be used
Verapamil comes as a regular tablet and as an extended-release (long-acting) tablet and capsule to take by mouth. The regular tablet is usually taken three times a day. The extended-release tablet and capsule are usually taken one or two times a day and should be swallowed whole. Do not chew, divide, or crush the extended-release tablet or capsule. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take verapamil exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Verapamil controls arrhythmias, high blood pressure, and chest pain (angina) but does not cure them. Continue to take verapamil even if you feel well. Do not stop taking verapamil without talking to your doctor.
Other uses for this medicine
Verapamil is also used sometimes to treat migraine headaches and cardiomyopathy. Talk to your doctor about the possible risks of using this drug for your condition.
Special precautions
Before taking verapamil:
- tell your doctor and pharmacist if you are allergic to verapamil or any other drugs.
- tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially aspirin, carbamazepine (Tegretol); cyclosporine (Neoral, Sandimmune); fentanyl (Duragesic); heart and blood pressure medications such as beta-blockers, digoxin (Lanoxin), disopyramide (Norpace), flecainide (Tambocor), quinidine (Quinaglute, Quinidex), diuretics ('water pills'), or any other blood pressure lowering medication; lithium (Eskalith, Lithobid); medications to treat depression; medications to treat glaucoma (increased pressure in the eye); phenobarbital; rifampin (Rifadin, Rimactane); theophylline (Theo-Dur); and vitamins.
- tell your doctor if you have or have ever had heart, liver, or kidney disease, muscular dystrophy, or gastrointestinal obstruction (strictures).
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking verapamil, call your doctor.
- if you are having surgery, including dental surgery, tell your doctor or dentist that you are taking verapamil.
- you should know that verapamil may increase the effects of alcohol and make them last longer.
Special dietary instructions
Verapamil may cause an upset stomach. Take verapamil with food or milk.
Talk to your doctor before using salt substitutes containing potassium. If your doctor prescribes a low-salt or low-sodium diet, follow these directions carefully.
What to do if you forget a dose
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
Side Effects
Minor Side Effects
Verapamil may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- constipation
- dizziness or lightheadedness
- headache
- upset stomach
- heartburn
- excessive tiredness
- flushing (feeling of warmth)
- slow heartbeat
- vivid, unusual dreams
Severe Side Effects
If you experience any of the following symptoms, call your doctor immediately:
- swelling of the face, eyes, lips, tongue, arms, or legs
- difficulty breathing or swallowing
- fainting
- rash
- yellowing of the skin or eyes
- fever
- increase in frequency or severity of chest pain (angina)
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/MedWatch/report.htm] or by phone [1-800-332-1088].
Storage conditions needed for this medication
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of emergency/overdose
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Other information
Keep all appointments with your doctor and the laboratory. Your blood pressure should be checked regularly to determine your response to verapamil.
Your doctor may ask you to check your pulse (heart rate) daily and will tell you how fast it should be. If your pulse is slower than it should be, call your doctor for directions on taking verapamil that day. Ask your doctor or pharmacist to teach you how to check your pulse.
The extended-release tablet (Covera) does not dissolve in the stomach after being swallowed. It slowly releases medicine as it passes through the small intestines. It is not unusual to see the tablet shell eliminated in the stool.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
Brand names
- Calan®
- Calan® SR Caplets®
- Covera-HS®
- Isoptin® SR
- Verelan®
- Verelan® PM
Brand names of combination products
- Tarka® containing Verapamil Hydrochloride and Trandolapril