Key takeaways:
Calcium channel blockers (CCBs) are medications that treat high blood pressure and other heart-related health conditions.
Common CCB side effects include constipation, swelling in the arms and legs, and a slow heart rate. Fatigue, flushing, and dizziness can also occur.
CCBs can cause worsening of heart problems, such as heart failure. These medications are usually avoided in people with heart failure.
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Have you recently received a prescription for a calcium channel blocker (CCB)? If so, you’ll be benefitting from a medication that promotes heart health by relaxing blood vessels throughout your body. This popular group of medications treats high blood pressure and other cardiac-related health conditions.
What’s more, there are two groups of CCBs. Dihydropyridine (DHP) CCBs are most abundant, as many CCBs fall into this category. Their drug names tend to end in -pine, with top examples being amlodipine (Norvasc, Katerzia) and nifedipine (Procardia).
Non-dihydropyridine (non-DHP) CCBs are also available. Rather than focusing on your blood vessels, they prioritize managing the speed and strength of your heart beat. The two non-DHP CCBs are diltiazem (Cardizem, others) and verapamil (Verelan, Calan SR).
You may be familiar with one or more of these medications. But it can be hard to remember their benefits and risks. While each CCB is unique, here are seven possible CCB side effects to keep in mind.
1. Constipation
Constipation occurs when bowel movements become difficult or infrequent. It’s a common side effect of many medications, and CCBs are no exception.
This side effect is thought to be connected to how CCBs work. While they’re relaxing smooth muscles in your blood vessels, they can also relax stomach muscles. This can contribute to constipation.
While constipation has been reported for many CCBs, some tend to cause more constipation than others. Verapamil and diltiazem are the biggest culprits. Verapamil appears to have the highest risk, with up to 11% of people experiencing this side effect while taking it.
Fortunately, there are ways to help ease this unwanted side effect. Adjusting your diet to include plenty of fiber, getting an adequate amount of water, and routine exercise can help manage it. Several over-the-counter (OTC) laxatives are also available to help move things along, as well. But these are generally used for short-term relief, not long-term treatment; talk to your healthcare provider to determine if an OTC laxative is right for you.
2. Swelling in your arms or legs
Edema, or swelling in your arms or legs from fluid buildup, is another common side effect of CCBs.
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This fluid buildup is more likely to happen in certain groups of people. Research has shown that swelling is more common in women taking CCBs compared to men. Research also shows that there’s a possible link between edema and increased age. Warm environments, such as seasonal weather or work conditions, can also make things worse.
What’s more, certain CCBs are more prone to cause swelling than others. Specifically, DHP CCBs are about four times more likely to cause arm and leg swelling compared to non-DHP CCBs. Higher doses of CCBs and longer durations of treatment have also been linked to an increased risk of edema.
Unfortunately, swelling from CCBs doesn’t always get better with time. But there are still ways to combat it. Elevating your legs or using compression socks can help ease swelling. Taking your medication in the evening may also help. In more severe cases, switching to another medication may be warranted.
3. Slow heart rate
A low heart rate, or bradycardia, is another possible CCB side effect. It’s more likely with non-DHP CCBs. Non-DHP CCBs, like diltiazem and verapamil, decrease the amount of work your heart has to do by slightly lowering your heart rate.
A lower heart rate from taking a CCB shouldn’t cause you to feel symptoms of bradycardia. However, if you feel symptoms like dizziness or shortness of breath, there’s a chance your heart rate could be too low.
4. Dizziness
Dizziness is the feeling of being unsteady, lightheaded, or weak. This can happen when first starting a CCB or if your blood pressure has gone down too much. This feeling can also occur when you move from a lying down or sitting position to standing up, so it’s important to move positions slowly while taking your medication.
Dizziness occurs more frequently in people taking higher doses of CCBs. This side effect should improve over time as your body gets used to your medication. Contact your healthcare provider if you feel bothered or uncomfortable by the extent of your dizziness.
5. Fatigue
Fatigue is another common CCB side effect. In fact, many blood pressure medications can make you feel like you’re dragging behind.
Like dizziness, fatigue should improve as your body adjusts to your CCB. In the meantime, exercising and eating healthy can help boost your energy levels. Drinking plenty of water and electrolytes may also help.
Contact your healthcare provider if your fatigue noticeably worsens or becomes bothersome. It’s important to be sure your symptoms aren’t being caused by having an excessively low heart rate or blood pressure.
6. Flushing
Flushing, or when your skin gets red and warm to the touch, is another common side effect of CCBs. This is more common in people who take a DHP CCB like amlodipine. This side effect happens as a result of blood vessel widening, which causes more blood to enter your tissues.
Women are about three times as likely to experience flushing from CCBs compared to men. This side effect also appears to be dose-related, meaning a higher dose correlates to a higher risk of flushing.
Fortunately, this side effect should go away once your body gets used to the CCB. Let your healthcare provider know if your flushing becomes bothersome or it lingers.
7. Worsening heart problems
CCBs are effective treatment options for certain heart conditions, such as high blood pressure and coronary artery disease. However, some CCBs also have the ability to worsen other types of heart problems, such as heart failure.
This is especially true for a specific form of heart failure called systolic heart failure. Because of this, most CCBs aren’t generally recommended for people who are living with heart failure. This potentially serious risk is more relevant among people who take verapamil or diltiazem.
When should I contact my healthcare provider about calcium channel blocker side effects?
Most side effects associated with CCBs are mild and manageable. They should subside as your body adjusts to your medication. Although some side effects can linger on, it’s not normal for them to get worse with time. Alert your healthcare provider if this becomes the case.
It’s also important to report significant episodes of dizziness or fatigue to your healthcare provider. They may want to check that your blood pressure and heart rate aren’t too low and that the dose of your medication is appropriate.
Certain situations warrant more immediate medical attention. Go to the nearest emergency room if you experience sudden chest pain or shortness of breath. These symptoms may or may not be related to your CCB, but it’s important to get evaluated and treated right away.
The bottom line
Common calcium channel blocker side effects include constipation, reduced heart rate, and fatigue. Dizziness, flushing, and edema are also possible. Side effects like these are often mild and temporary, but some serious risks are also possible. Most CCBs should be avoided in people with heart failure, especially in those with systolic heart failure. Keep in mind that specific side effects vary by person and medication.
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References
American Heart Association. (2017). Types of heart failure.
Elsevier. (2012). Calcium channel blockers.
Elsevier. (2021). Calcium channel blockers.
Makani, H., et al. (2011). Peripheral edema associated with calcium channel blockers: Incidence and withdrawal rate – a meta-analysis of randomized trials. Journal of Hypertension.
McKeever, R. G., et al. (2022). Calcium channel blockers. StatPearls.
Natale, F., et al. (2011). Worsening of rosacea in patients treated with dihydropyridine calcium channel blockers: a clinical observation. Hypertension Research.
Sica, D. A. (2007). Calcium channel blocker-related peripheral edema: Can it be resolved?The Journal of Clinical Hypertension.
