Naomi Carr
Author: Naomi Carr Medical Reviewer: Dr. Leila Khurshid Last updated:

Verapamil is a calcium-channel blocker used for treating various heart conditions and sometimes for the treatment of bipolar disorder. Take this medication exactly as prescribed. Always consult your doctor or pharmacist before starting a new medication (prescribed or over the counter) while taking verapamil, as adverse effects can occur.

Verapamil brand names

  • Calan
  • Calan SR
  • Covera HS
  • Isoptin (discontinued)
  • Verelan
  • Verelan PM

What is verapamil prescribed for?

Verapamil is prescribed to treat various heart conditions, including angina, high blood pressure, and tachycardia.[1]

Calcium channel blockers, such as verapamil, are also used in treating bipolar disorder, particularly acute manic phases.[2]

The U.S. Food and Drug Administration (FDA) has not determined the effectiveness or safety of verapamil for bipolar disorder, so it is not an approved use of this medication and is instead used off-label. However, there is research and evidence to suggest that it can be a useful treatment for bipolar [2][3][4], and it may be prescribed by a medical professional for this purpose.

How does verapamil work?

Verapamil blocks calcium from entering certain parts of the brain, which results in the relaxation of the brain and heart muscle and a reduction of certain brain activity. [1][2]

As such, it can reduce the symptoms of various heart conditions but may also reduce symptoms of bipolar disorder by stabilizing mood.

How is verapamil usually taken?

Verapamil is available an oral tablet, both immediate-release and extended-release, and as an extended-release capsule.

Tablets must be swallowed whole without being crushed or broken.

Capsules should be swallowed whole without crushing. Alternatively, they can be opened, and the medication sprinkled over a soft food, such as applesauce, which can then be swallowed without chewing.

Immediate-release verapamil is generally taken 3-4 times per day, as the medication is released and absorbed into the body very quickly. On the other hand, extended-release medication is generally taken 1-2 times per day, as it is released more slowly into the body, having a longer-lasting effect.

Your doctor will likely initially prescribe you a low dose of verapamil, closely monitoring any changes in your physical or mental state. This dose can then be increased gradually to find the most effective dose for you.

Your dose may depend on the severity of your condition, your age, weight, and response to the medication.

Ensure you take your medication exactly as prescribed, using the correct type of verapamil, the correct dose, and the correct times, for the duration of the medical treatment.

If you forget one dose, take it as soon as you remember, or if it is near your next dose, skip the missed dose and take the next. Never take double your prescribed dose, as adverse effects can occur.

How long does verapamil stay in your system?

When you start taking verapamil, you may notice some changes in your symptoms within the first week or two, although it may take several weeks for the medication to take full effect.

After verapamil is stopped, it may take 1-2 weeks for the medication to fully leave your system, depending on the dosage and length of your treatment. [5]

Never suddenly stop taking verapamil, even if you feel better, as this can cause adverse effects on both your mental and physical health. However, if your doctor advises that it is safe to stop taking this medication, they will likely reduce your dose slowly to prevent adverse effects.

Verapamil side effects

When you start a new medication, you may experience some common side effects. These should reduce within the first week or two, but if they continue or become problematic, consult your doctor, as you may need a change of dose or medication.

Common side effects of verapamil include:

  • Heartburn
  • Constipation
  • Dizziness
  • Headache

Serious side effects of verapamil are less common but may still occur. If you experience any of the following, contact your doctor immediately:

  • Extreme tiredness
  • Swelling of the hands or feet
  • Breathing difficulties
  • Fainting
  • Blurry vision
  • Unexplained bruising or bleeding
  • Loss of appetite or weight
  • Stomach pain
  • Yellowing of the face or eyes
  • Fever or sweating

Verapamil precautions

Discuss with your doctor all your past and present physical health conditions, as this may impact your ability to take verapamil safely.

Because of the potential side effects, you may not be able to take this medication if you have experienced certain heart, liver, kidney, digestive, muscular, or breathing-related conditions. However, if your doctor deems it necessary for you to take this medication, they will closely monitor any changes in your physical health, and you may be prescribed a lower dose.

It is important that your doctor is aware of any past or present mental health conditions you have experienced to enable safe monitoring of your condition while on this medication or to decide if it is safe for you.

Tell your doctor and pharmacist about all medications you are taking or plan to take (including vitamins and dietary supplements), as they may cause adverse reactions.

Inform your doctor if you are pregnant or planning to become pregnant. Verapamil may harm your fetus, so it is important that you are aware of the risks so that you can make an informed decision about your treatment. If it is deemed necessary to take this medication while pregnant, your doctor will closely monitor the physical health of your fetus, particularly heart functioning.[1]

If you are breastfeeding, it may be safe to take this medication. However, very small amounts of verapamil may pass to your baby through breast milk, so it is advised to use it cautiously and to carefully monitor your baby for any unusual changes in its physical or mental state.

Verapamil interactions

Some medications or substances may interact with verapamil, impacting the effectiveness of the medication or increasing the risk of serious side effects. This includes some antibiotic and antifungal medications, beta blockers, diuretics, blood pressure medication, lithium, St. John’s wort, and some other psychiatric medications.

It is advised to avoid or limit alcohol use while taking verapamil, as the medication can increase the effects of alcohol [6].

Large amounts of grapefruit or grapefruit juice should not be consumed with verapamil, as it can increase the effects of the medication, increasing the risk of side effects.

Verapamil storage

Always keep all medications out of reach of children.

Store verapamil in its original packaging, in airtight containers, and at room temperature (never above 86 F).

If you need to dispose of medication that is expired or no longer needed, contact a medical professional to ensure it is disposed of appropriately. Never flush medications down the toilet or put them in the trash, as this can create unnecessary risks.

What to do if you overdose on verapamil

If you overdose on verapamil, call a medical professional or Poison Control at 1-800-222-1222, or in case of an emergency, call 911. Symptoms of a verapamil overdose include breathing difficulties, feeling dizzy, irregular heartbeat, seizure, coma, or even death.


How long does verapamil take to work?

Verapamil may take up to two weeks to be in full effect. You may notice changes in your symptoms within this time. If you have not noticed any improvements within 2-3 months, inform your doctor, as it may be that this medication is not the best treatment for you, and you may need to try alternatives.[2][5]

Are there any alternatives to verapamil?

There are several medications available for the treatment of bipolar disorder. Some of these medications include lithium; anticonvulsant medications, such as lamotrigine, valproate, and carbamazepine; antipsychotic medications, such as aripiprazole and risperidone; and antidepressant medications, such as fluoxetine and citalopram.[7]

You can discuss alternative medications with your doctor, who can advise you on the benefits and side effects of each medication so that you can make an informed decision about your treatment.

People often respond to medications differently, so what works for one person may not work for another. Therefore, you may need to try more than one or a combination of medications to find what works well for you.

You may also wish to engage in talking therapy alongside your medication, as this is often the most effective treatment plan to help you manage your condition.[8]

  1. Fahie, S., & Cassagnol, M. (2022). Verapamil. In StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing. Retrieved from
  2. Cipriani, A., Saunders, K., Attenburrow, M. J., Stefaniak, J., Panchal, P., Stockton, S., Lane, T. A., Tunbridge, E. M., Geddes, J. R., & Harrison, P. J. (2016). A Systematic Review of Calcium Channel Antagonists in Bipolar Disorder and Some Considerations for their Future Development. Molecular Psychiatry21(10), 1324–1332. Retrieved from
  3. Wisner, K. L., Peindl, K. S., Perel, J. M., Hanusa, B. H., Piontek, C. M., & Baab, S. (2002). Verapamil Treatment for Women with Bipolar Disorder. Biological Psychiatry51(9), 745–752. Retrieved from
  4. Mallinger, A. G., Thase, M. E., Haskett, R., Buttenfield, J., Luckenbaugh, D. A., Frank, E., Kupfer, D. J., & Manji, H. K. (2008). Verapamil Augmentation of Lithium Treatment Improves Outcome in Mania Unresponsive to Lithium Alone: Preliminary Findings and a Discussion of Therapeutic Mechanisms. Bipolar Disorders10(8), 856–866. Retrieved from
  5. Follath, F., Ha, H. R., Schütz, E., & Bühler, F. (1986). Pharmacokinetics of Conventional and Slow-Release Verapamil. British Journal of Clinical Pharmacology21 Suppl 2(Suppl 2), 149S–153S. Retrieved from
  6. Verapamil: MedlinePlus Drug Information. (Revised 2017). MedlinePlus. Retrieved from
  7. Geddes, J. R., & Miklowitz, D. J. (2013). Treatment of Bipolar Disorder. Lancet (London, England)381(9878), 1672–1682. Retrieved from
  8. Bipolar Disorder. (n.d.) NAMI. Retrieved from
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Naomi Carr
Author Naomi Carr Writer

Naomi Carr is a writer with a background in English Literature from Oxford Brookes University.

Published: Nov 23rd 2022, Last edited: Oct 12th 2023

Dr. Leila Khurshid
Medical Reviewer Dr. Leila Khurshid PharmD, BCPS

Dr. Leila Khursid is a medical reviewer with a Doctor of Pharmacy degree and completed a PGY1 Pharmacy Residency from St. Mark's Hospital.

Content reviewed by a medical professional. Last reviewed: Nov 23rd 2022