Name: Verapamil

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.

Symptoms of overdose may include:

  • dizziness
  • blurred vision
  • slow, fast, or irregular heartbeat
  • seizures
  • confusion
  • difficulty breathing or swallowing

What Is Verapamil (Calan, Covera HS, Isoptin SR, Verelan)?

Calan, Covera HS, Isoptin SR, Verelan are the brand names of the drug verapamil, which is used to treat high blood pressure and control chest pain known as angina.

The immediate-release tablet form of this medication is also used to prevent and treat irregular heartbeats (arrhythmia).

Although this medicine is not approved by the FDA for migraines, it is often prescribed for preventing them.

Verapamil is in a class of drugs called calcium channel blockers. It works by relaxing blood vessels so the heart doesn't have to work as hard, increasing the supply of blood and oxygen to the heart, and slowing electrical activity in the heart to control heart rate.

Verapamil was approved by the Food and Drug Administration (FDA) in 1981.

The drug comes as a tablet, an extended-release tablet, and an extended-release capsule to take by mouth and injectable solution.

Verapamil is on the World Health Organization's "List of Essential Medicines," a list of the most important drugs needed in a basic health care system.

Verapamil Warnings

This medicine controls high blood pressure, arrhythmia, and angina, but it does not cure these conditions. You should continue to take verapamil even if you feel well.

Before taking verapamil, tell your doctor if you have or have ever had:

  • Any condition that causes food to move through your digestive system more slowly
  • Myasthenia gravis (a condition that causes certain muscles to weaken)
  • Heart failure
  • Heart, liver, or kidney disease
  • Muscular dystrophy (an inherited disease that causes weakening of the muscles).

You should also tell your doctor you are taking verapamil before any type of surgery, including dental procedures.

Your doctor will likely start you on a low dose of verapamil and then gradually increase your dose.

You should keep all appointments with your doctor while taking this medicine. You will need your blood pressure checked regularly to determine how you are responding to verapamil.

If you take a certain version of the extended-release tablets, you might notice an empty tablet shell in your stool. This does not mean that you did not receive your complete dose of medication.

Pregnancy and Verapamil

The safety of verapamil during pregnancy and while breastfeeding has not been determined.

What is the most important information i should know about verapamil?

You should not use verapamil if you are allergic to it, or if you have certain serious heart conditions such as "sick sinus syndrome" or "AV block" (unless you have a pacemaker), low blood pressure, or if you have recently had a heart attack.

Before taking verapamil, tell your doctor if you are allergic to any drugs, or if you have kidney disease, liver disease, congestive heart failure, or a nerve-muscle disorder such as myasthenia gravis or muscular dystrophy.

There are many other drugs that can interact with verapamil. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor. Keep a list of all your medicines and show it to any healthcare provider who treats you.

Verapamil may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Do not stop taking this medication without first talking to your doctor. If you stop taking verapamil suddenly, your condition may become worse.

Verapamil may be only part of a complete program of treatment that also includes diet, exercise, and other medications. Follow your diet, medication, and exercise routines very closely.

If you are being treated for high blood pressure, keep using this medication even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.

What happens if i miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Commonly used brand name(s)

In the U.S.

  • Calan
  • Calan SR
  • Covera-HS
  • Isoptin SR
  • Verelan
  • Verelan PM

Available Dosage Forms:

  • Tablet, Extended Release
  • Capsule, Extended Release
  • Tablet
  • Tablet, Extended Release, 24 HR
  • Capsule, Extended Release, 24 HR

Therapeutic Class: Cardiovascular Agent

Pharmacologic Class: Calcium Channel Blocker

Chemical Class: Phenylalkylamine

Proper Use of verapamil

In addition to the use of verapamil, treatment for your high blood pressure may include weight control and changes in the types of foods you eat, especially foods high in sodium. Your doctor will tell you which of these are most important for you. You should check with your doctor before changing your diet .

Many patients who have high blood pressure will not notice any signs of the problem. In fact, many may feel normal. It is very important that you take your medicine exactly as directed and that you keep your appointments with your doctor even if you feel well .

Remember that verapamil will not cure your high blood pressure, but it does help control it. You must continue to take it as directed if you expect to lower your blood pressure and keep it down. You may have to take high blood pressure medicine for the rest of your life. If high blood pressure is not treated, it can cause serious problems such as heart failure, blood vessel disease, stroke, or kidney disease .

Swallow the extended-release tablet whole with a full glass of water. Do not break, crush, or chew it. It is best to take verapamil with food .

If you cannot swallow the verapamil extended-release capsules, you may open it and sprinkle the pellets contained in the capsule on one tablespoon of applesauce. This mixture must be swallowed immediately with a glass of cool water. The applesauce should not be hot and should be soft enough to be swallowed without chewing. Do not chew or crush the pellets .

If you are taking the extended-release tablets, you may sometimes notice what looks like a tablet in your stool. This is the empty tablet shell that is left after the medicine has been absorbed .


The dose of verapamil will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of verapamil. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For chest pain:
    • For oral dosage form (tablets):
      • Adults—The usual dose is 80 to 120 milligrams (mg) three times a day. Your doctor may adjust your dose if needed.
      • Children—Use and dose must be determined by your doctor .
    • For oral dosage form (extended-release tablets, 24 hr):
      • Adults—At first, 180 milligrams (mg) once daily at bedtime. Your doctor may adjust your dose if needed.
      • Children—Use and dose must be determined by your doctor .
  • For heart rhythm problems:
    • For oral dosage form (tablets):
      • Adults—The total usual dose is 240 to 480 milligrams (mg) divided in three or four equal doses per day.
      • Children—Use and dose must be determined by your doctor .
  • For high blood pressure:
    • For oral dosage form (tablets):
      • Adults—At first, 80 milligrams (mg) three times a day. Your doctor may adjust your dose if needed.
      • Children—Use and dose must be determined by your doctor .
    • For oral dosage form (extended-release capsules):
      • Adults—At first, 200 milligrams (mg) once daily at bedtime. Your doctor may adjust your dose if needed.
      • Children—Use and dose must be determined by your doctor .
    • For oral dosage form (extended-release tablets):
      • Adults—At first, 180 milligrams (mg) once daily in the morning. Your doctor may adjust your dose if needed.
      • Children—Use and dose must be determined by your doctor .
    • For oral dosage form (extended-release tablets, 24 hr):
      • Adults—At first, 180 milligrams (mg) once daily at bedtime. Your doctor may adjust your dose if needed.
      • Children—Use and dose must be determined by your doctor .

Missed Dose

If you miss a dose of verapamil, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule Extended Release 24 Hour, Oral, as hydrochloride:

Verelan: 120 mg, 180 mg [contains fd&c red #40, methylparaben, propylparaben]

Verelan: 240 mg, 360 mg [contains brilliant blue fcf (fd&c blue #1), fd&c red #40, methylparaben, propylparaben]

Verelan PM: 100 mg, 200 mg, 300 mg [contains brilliant blue fcf (fd&c blue #1), fd&c red #40]

Generic: 100 mg, 120 mg, 180 mg, 200 mg, 240 mg, 300 mg, 360 mg

Solution, Intravenous, as hydrochloride:

Generic: 2.5 mg/mL (2 mL, 4 mL)

Tablet, Oral, as hydrochloride:

Calan: 80 mg, 120 mg [scored]

Generic: 40 mg, 80 mg, 120 mg

Tablet Extended Release, Oral, as hydrochloride:

Calan SR: 120 mg

Calan SR: 180 mg [scored]

Calan SR: 240 mg [scored; contains fd&c blue #2 aluminum lake, fd&c yellow #10 aluminum lake]

Generic: 120 mg, 180 mg, 240 mg

Special Populations Elderly

Elimination half-life may be prolonged and bioavailability higher in the elderly.

Dosing Pediatric

SVT: Note: Verapamil is not included in the Pediatric Advanced Life Support (PALS) tachyarrhythmia algorithm. Optimal interval for subsequent doses is unknown and must be individualized for each specific patient.

Children and Adolescents 1 to 15 years: IV, Intraosseous: 0.1 to 0.3 mg/kg/dose over 2 minutes; maximum: 5 mg/dose, may repeat dose in 15 to 30 minutes if inadequate response; maximum for second dose: 10 mg (Kliegman 2016; PALS [Kleinman 2010]; Park 2014)

Adolescents >15 years: IV:


Manufacturer labeling: 5 to 10 mg (0.075 to 0.15 mg/kg)

PALS guidelines: 0.1 to 0.3 mg/kg/dose; maximum dose: 5 mg/dose (PALS [Kleinman 2010]; Park 2014)

Repeat dose: May repeat dose in 15 to 30 minutes if adequate response not achieved; maximum for second dose: 10 mg/dose (Kliegman 2015; PALS [Kleinman 2010]; Park 2014)

Dosing Hepatic Impairment

Oral: In cirrhosis, reduce dose to 20% of normal and monitor ECG (Somogyi 1981).

Calan, Calan SR, Verelan: Administer 30% of the normal dose in severe hepatic impairment.

Verelan PM: Initial: 100 mg once daily at bedtime.

Injection: There are no dosage adjustments provided in the manufacturer’s labeling; use with caution and consider additional ECG monitoring in severe impairment. In cirrhosis, reduce dose to 50% of normal and monitor ECG (Somogyi, 1981). Repeated injections in patients with hepatic failure may lead to accumulation and excessive pharmacologic effects and should be avoided. If repeated injections are essential, monitor blood pressure and PR interval closely and use smaller repeat doses.

Usual Adult Dose for Supraventricular Tachycardia

-Initial dose: 5 to 10 mg (0.075 to 0.15 mg/kg) IV bolus over at least 2 minutes
-Repeat dose: 10 mg (0.15 mg/kg) IV (over 2 minutes) 30 minutes after the initial dose if the response is inadequate

-Each dose should be administered over at least 2 minutes under continuous ECG and blood pressure monitoring.

Use: Treatment of supraventricular tachyarrhythmia, including:
-Rapid conversion to sinus rhythm of paroxysmal supraventricular tachycardia, including those associated with accessory bypass tracts
-Temporary control of rapid ventricular rate in atrial flutter/fibrillation EXCEPT when atrial flutter/fibrillation are associated with accessory bypass tracts

Renal Dose Adjustments

Oral formulations: Use with caution.
Parenteral formulations: In general, multiple doses in patients with renal impairment should be avoided. If repeated injections are essential, smaller repeat doses are recommended.


  • May be used as an ongoing treatment to relieve symptoms such as chest pain in people with unstable or chronic stable angina, or angina due to coronary artery spasm. Will not relieve acute episodes of angina (other medications such as sublingual nitroglycerin are used for this purpose).
  • May be used to treat certain arrhythmias such as atrial fibrillation, atrial flutter, and repetitive paroxysmal supraventricular tachycardia.
  • May be used for the treatment of high blood pressure (hypertension), alone or in combination with other agents for high blood pressure.
  • Available as immediate-release tablets, extended/sustained-release tablets and capsules, and in an injectable form.
  • Generic verapamil is available.


If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Constipation, dizziness, headache, facial flushing, nausea, low blood pressure, edema, elevated liver enzymes, sexual dysfunction, and shortness of breath. May also cause cold-like symptoms such as a stuffy nose, sinus pain, and sore throat.
  • May interact with a number of different medications including some anti-infectives, tuberculosis medications, other drugs to manage blood pressure or arrhythmias, statins, and grapefruit products.
  • May not be suitable for some people including those with certain preexisting heart conditions including severe heart failure and hypotension. People with kidney or liver disease may need extra monitoring.
  • Verapamil is not FDA approved for people younger than 18 years.

Notes: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. For a complete list of all side effects, click here.

Response and Effectiveness

  • Peak levels of verapamil are reached one to two hours after oral administration. Peak levels may be increased in people with liver disease or of an older age.

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