Calcium Channel Blockers

Calcium channel blockers are most often used to treat high blood pressure, also called hypertension. Some drugs in this class have been used to prevent migraine attacks, since they are easy to use and have few side effects.¹

However, the most recent guidelines put out by the American Headache Society in 2018 do not include calcium channel blockers in their table of treatments with evidence of effectiveness to prevent migraine.² Instead, calcium channel blockers have been downgraded to a status (Level U) that states: “Evidence is conflicting or inadequate to support or refute the use of the following medications for migraine prevention.³

It’s possible that calcium channel blockers could be used in patients who are not good candidates for other first-line preventive medications like beta blockers, because of other health concerns.

When they are used, calcium channel blockers can sometimes lose their effectiveness over time, but this can often be helped by taking a higher doses or switching to a similar drug.

How do calcium channel blockers work?

Calcium channel blockers (also called calcium antagonists) prevent calcium from entering cells of the heart and blood vessel walls. This helps prevent the muscles in the vessels from contracting and tightening. As a result, the blood vessels relax and widen, which leads to lower blood pressure. Some calcium channel blockers work more specifically on the heart muscle and others work better on blood vessels.⁴

What are some calcium channel blockers?

• Nicardipine (Cardene®)
• Nifedipine (Adalat®, Procardia®, Afeditab®)
• Nimodipine
• Verapamil (Calan® , Covera® , Verelan®)

What are some side effects of calcium channel blockers for migraine?

• Dizziness
• Drowsiness
• Constipation
• Nausea
• Headache
• Rash
• Swelling of the legs with fluid, edema
• Low blood pressure
• Rapid heartbeat, tachycardia
• Sudden reddening of the face, neck or upper chest, flushing

These are not all the possible side effects of calcium channel blockers. Patients should talk to their doctor about what to expect with calcium channel blockers as treatment.

What else should I know about calcium channel blockers?

Calcium channel blockers shouldn’t be taken with grapefruits or grapefruit juice. Grapefruit reduces the liver’s ability to eliminate the drug from your system, which could cause a dangerous build-up of the medication in your body.

It is important not to take calcium channel blockers if you have had a recent heart attack or have uncontrolled high blood pressure.

Before you begin calcium channel blockers, tell your doctor if:

• You are allergic to the medication
• You have heart problems besides angina or high blood pressure
• You are pregnant or breastfeeding
• You have diabetes
• You have liver problems
• You are taking or using any other medicines, supplements, or vitamins⁵

You should begin no medication or supplement without first checking with your health care provider and should let them know of any other prescriptions, OTCs, and herbals you are taking to ensure there are no interactions.