COMMON BRANDS: Calan, Isoptin, Isoptin SR, Calan SR, Covera HS, Isoptin IV, Verap, Verapamil SR, Verelan, Verelan PM

Verapamil is an oral prescription drug, belongs to a class of medications known as calcium channel blockers. It works by reducing arterial blood pressure by vasodilation blood vessels throughout your body thereby reducing peripheral vascular resistance and also increases the supply of blood and oxygen to the heart. This result in less pressure to built up and slow down your heart rate thereby reducing its workload.

Verapamil is available in both brand-name version and generic-name version. Brand name version is available as an immediate-release, extended-release tablet and delayed-release capsule. The verapamil tablet is sold under the common brand “Calan” and “Calan SR”, whereas the capsule is sold under the common brand “Verelan”.

What is Verapamil used for?


Verapamil is either used alone or in combination with other medications to treat high blood pressure. Lowering high blood pressure prevents strokes, heart attacks, and kidney problems.


Verapamil is also used to treat certain types of chest pain (chronic stable angina). It may also increase your ability to exercise and limit the frequency of angina attacks. It should be avoided to treat attacks of chest pain when they happen.

Atrial fibrillation and supraventricular tachycardia:

This drug is also used to treat chronic atrial fibrillation (irregular and often rapid heart rate), supraventricular tachycardia (abnormally rapid heartbeat that originates above the ventricles) and tardive dyskinesia along with other drugs.

Verapamil also used to treat Migraines.

How to use Verapamil?

Verapamil immediate-release tablet usually taken three or four times with or without food in a day and extended-release tablet should be taken once a day with or without meals. Certain verapamil brands should be taken in the morning and others at bedtime. Discuss with your doctor what the best time is for you to take your medication.

Swallow the whole tablets; do not split, chew, or crush them.

If you can’t, swallow the whole capsule, carefully open the capsule and sprinkle the contents on a spoonful of applesauce. Make sure that the applesauce is not hot, and it should be soft enough to be swallowed. Swallow the applesauce right away without chewing, and then drink a glass of water to assure that you have consumed all of the medicine. Do not store the mixture for further use.

The dose of the drug depends upon your medical examination and response to treatment. Your doctor may slowly increase your dose if needed.

To help you remember to take this drug, take it at around the same time every day. Carefully follow all the directions on your prescription label and discuss with your doctor or pharmacist if you have any doubt.

Take verapamil precisely as instructed. Do not alter your dosage or take it more frequently than prescribed by your doctor.

In the case of angina, this medication must be taken without missing to be effective. It should not be used in the treatment of angina when chest pain occurs. Use other drugs (for example sublingual nitroglycerin) to reduce attacks of chest pain as directed by your doctor. Discuss with your doctor for further information.

Notify your doctor if your health does not improve or if it worsens (for example, your blood pressure remain high or increase, chest pain persists or worsens).

What are the side effects of Verapamil?

The commonly observed side effects with the use of this drug include dizziness or lightheadedness, a headache, nausea, vomiting, rash, flushing, edema (swelling in the legs or feet), weakness. Inform your doctor/pharmacist immediately, If any of these side effects continue or worsen.

To lower your danger of dizziness and lightheadedness, stand up slowly when rising from a sitting or lying position.

Get emergency medical assistance promptly, if you notice any of the following serious side effects like chest pain getting worse, symptoms of a heart attack (like chest pain radiating to jaw/left arm, shortness of breath, unusual sweating. edema), low blood pressure or low heart rate (symptoms like lightheadedness, fainting), fast/irregular/pounding heartbeat.

Rarely this drug may cause liver damage symptoms like yellowing of the skin and whites of the eyes, dark-colored urine, stomach pain. If you notice any of these effects notify your doctor right away.

Severe allergic reaction to this drug is uncommon. However, get medical assistance help right away if you notice any symptoms of a severe allergic reaction, severe dizziness, rash, itching/swelling (especially of the face/tongue/throat), trouble breathing.

This is not a full record of all possible side effects. Inform your doctor at the earliest, if you notice any of the side effects that are not mentioned in this article.

What are the precautions while using Verapamil?

Inform your doctor/pharmacist before taking Verapamil, if you are allergic to it; or if you have other allergies. This drug may also contain some inactive ingredients that can cause allergic reactions or other problems. Talk to your doctor/pharmacist for more information.

Inform your doctor/pharmacist about all the products you are using including prescription, non-prescription, vitamins, nutritional supplements, and herbal products.

Before taking this drug, tell your doctor or pharmacist about your medical history, mainly of liver problems, kidney problems, certain heart problems (such as congestive heart failure, aortic stenosis, myocardial infarction).

Verapamil may cause dizziness, do not drive, use machinery, or do anything that needs sharpness until you can do it cautiously. Limit use of alcoholic beverages. Speak to your doctor if you are using marijuana.

If you are undergoing any surgery, including dental surgery, inform your doctor that you are taking verapamil.

Older adults may be more likely susceptible to the side effects of this drug, mainly dizziness, constipation, swelling of ankles/feet.

This medication should be used only if needed during pregnancy and for more information about the safety of drug talk to your doctor.

This drug crosses into breast milk and may have undesirable effects on a nursing infant. Discuss with your doctor before breastfeeding.

What are the drug interactions of Verapamil?

Verapamil may interact with other medications, herbs, or vitamins you may be using. A drug interaction is when a substance changes the way a drug works which can be harmful or hinder the drug from working well.

Do not start, stop, or alter the dose of the drug without discussing your doctor because your doctor may be monitoring you for possible drug interactions.

Grapefruit juice may interact with this drug and increase its concentration. Discuss with your doctor about taking grapefruit juice with verapamil.

Using beta-blockers like metoprolol or propranolol, along with verapamil may cause additive negative effects like a decrease in heart rate, atrioventricular conduction, and cardiac contractility. For hypertensive patients, this combination should be used only with caution and regular monitoring.

Taking aspirin with verapamil may cause increased in bleeding times than observed with aspirin alone.

Long-term use of verapamil along with digoxin can increase the amount of digoxin in your body to toxic levels. Regular monitoring is required and if needed your doctor may decrease your digoxin dose.

In some patients, combining quinidine with verapamil may result in extremely low blood pressure. Avoid using these drugs.

Combining amiodarone with verapamil may affect heart contraction. This lead to a slow heart rate, heart rhythm problems, or reduced blood flow. Regular monitoring is needed.

Verapamil can interact with simvastatin, atorvastatin, lovastatin and increase their level in your body which results in more side effects. Dose adjustments may be required during co-administration of these drugs with verapamil.

Do not take eletriptan along with verapamil. Verapamil can increase the concentration of eletriptan in your body to 3 times. This can lead to toxic effects. Do not take eletriptan for at least 72 hours after you take verapamil.

Verapamil can increase the concentration of these medications such as lithium, carbamazepine, cyclosporine, theophylline in your body which result in more side effects.

Taking certain antibiotics like rifampin with verapamil decreases the levels of verapamil and make this drug less effective.

NSAIDs (such as ibuprofen, naproxen), a nasal decongestant (such as phenylephrine, pseudoephedrine), cough-and-cold products, may decrease the effectiveness of verapamil.



Verapamil may further decrease the blood pressure which results in symptomatic hypotension. Frequent monitoring of blood pressure is necessary. Dose adjustments are needed based on your clinical condition.

Cardiac Conduction:

Verapamil may cause slow heart rates, and this effect is more in the patients who are on beta-blockers or digitalis. Frequent monitoring of heart function is necessary. Dose adjustments are needed based on your clinical condition

Acute Hepatic Injury (Impaired liver function):

Verapamil mild increase liver enzymes like alkaline phosphatase, LDH, SGOT, SGPT. These elevated levels return to normal after stopping the medicine. Regular monitoring of liver function tests is necessary.

Second or third-degree heart block:

This drug is contraindicated in people with second or third degree AV block (but not in patients with a functioning artificial ventricular pacemaker).

What are the forms and strengths of Verapamil?

Generic: Verapamil

Form: Oral immediate-release tablet
Strengths: 40mg, 80mg, 120mg

Form: Oral extended-release tablet
Strengths: 120mg, 180mg, 240mg

Form: Oral extended-release capsule
Strengths: 100mg, 120mg, 180mg, 200mg, 240mg, 300mg

Brand: Calan
Form: Oral immediate-release tablet
Strengths: 80mg, 120mg

Brand: Calan SR
Form: Oral extended-release tablet
Strengths: 120mg, 240mg

Brand: Verelan
Form: Oral extended-release capsule
Strengths: 120mg, 180mg, 240mg, 360mg

Brand: Verelan PM
Form: Oral extended-release capsule
Strengths: 100mg, 200mg, 300mg

What is the dosage of Verapamil?

For Hypertension (high blood pressure):

Adult (18 and above):

Immediate-release tablet (Calan):

Initial dose: Take 180mg three times a day (240mg/day). The dose can be increased to 360–480mg/day but, a dose higher than 360mg/day generally do not provide added benefit.

Extended-release tablet (Calan SR):

Initial dose: Take 180mg every morning.
Dose increase: 240mg taken every morning or 180mg taken every morning and 180mg taken every evening or 240mg taken every morning plus 120mg taken every evening or 240mg taken every 12 hours.

Extended-release capsule (Verelan):

Initial dose: Take 120mg once per day in the morning.
Maintenance dose: Take 240mg once per day in the morning. The dose can be increased to 180mg, 240mg, 360mg, or 480mg.

Extended-release capsule (Verelan PM):

Initial dose: Take 200mg once per day at bedtime. The dose can be increased to 300mg or 400mg (two 200mg capsules) depending upon your response to treatment.

Geriatric (65 years and older):

Older adults are susceptible to the side effects of this drug due to slow kidney and liver function. To avoid this, your doctor may initiate your treatment on a low dose.

Special Considerations:

In case if you have a neuromuscular condition like Duchenne muscular dystrophy or myasthenia gravis, your doctor may decrease your dose of verapamil

Most common questions asked about Verapamil / Q&A’s:

What are the symptoms of Verapamil overdose?

Verapamil overdose symptoms may include dizziness, blurred vision, slow/fast/irregular heartbeat, confusion, seizures, difficulty breathing or swallowing. Seek a medical emergency as soon as possible if you experience any of these symptoms.


TheMedPharma has made every effort to make sure that all the information is factually correct, comprehensive, and up-to-date. However, this website should not be considered as a substitute for the advice, knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or licensed health care professional before taking any medication. The drug information contained herein is subjected to changes if required. The lack of warnings or other information for a given drug does not mean that the drug or its combination is safe, effective or appropriate for use in all patients.