Blood Pressure Medications: Calcium Channel Blockers for Hypertension

How do calcium channel blockers treat high blood pressure?

Hypertension Treatment: Calcium Channel Blockers
Choosing the right blood pressure medication. Hero Images

What is a Calcium Channel Blocker?

Calcium channel blockers are a common class of medication used to treat high blood pressure and heart arrhythmias (irregular heartbeats.) Calcium causes the forceful contraction of muscles in the heart and it also causes constriction of the muscles in the walls of the artery. Calcium channel blockers work by reducing the amount of calcium that flows into the heart muscle cells and the cell walls of the arteries.

This causes relaxation of  the blood vessels. When your blood vessels are not constricted, your blood flows easily and results in a lower blood pressure. Calcium channel blockers can also lower the heart rate and decrease the heart's pumping action.They are used to reduce the work of the heart for people who have chest pain from angina. Calcium channel blockers can be used in combination with other medications to lower blood pressure. The research of all available evidence by JNC 8 (Joint National Commission 8) has demonstrated an advantage to the use of calcium channel blockers in certain groups, particularly for the initial treatment of high blood pressure in African American people.The recommendations for treatment of hypertension in black people suggest beginning initial blood pressure treatment with a calcium channel blocker or a thiazide-type diuretic, even in patients with diabetes.

There Are Different Types of Calcium Channel Blockers

There are three different classes of calcium channel blockers, which include L-type, dihydropyridines, and non-dihydropryridines. Each class has different characteristics that make them suitable for treatment of specific conditions. Dihydropyridines are  used to treat high blood pressure, more frequently than the other classes of calcium channel blocker.

This is because they work well to reduce arterial blood pressure and vascular resistance. This class of drug usually ends with the suffix "-pine." Other calcium channel blockers, including diltiazem and verapamil, are used to treat rapid heart rates and angina. Calcium channel blockers are sometimes prescribed in combination forms with a statin or another blood pressure medication.

Examples of Calcium Channel Blockers

  • Verapamil (Calan, Verelan)
  • Amlodipine (Norvasc)
  • Diltiazem (Tiazac, Cardiazem, Dilacor)
  • Nifedipine (Procardia)
  • Nicardipine (Cardene)
  • Amlodipine and benazepril (Lotrel)
  • Amlodipine and atorvastatin (Caduet)
  • Amlodipine and valsartan (Exforge)

Cautions

When taking calcium channel blockers, you should be certain your doctor knows about all of your current medications and supplements, because calcium channel blockers can interact with other compounds. Grapefruit products, including juice, can interfere with metabolism and excretion of these medications, which can result in dangerously high levels of the drugs.

If you are taking a calcium channel blocker, you should wait at least four hours after taking the medication before consuming grapefruit or grapefruit juice.  Magnesium, which is a nutrient found in certain nuts, bananas, spinach, okra, brown rice, and shredded wheat cereal, has natural calcium channel blocker effects, so if your diet includes foods rich in magnesium, check with your doctor to determine if any adjustment is needed. You should not smoke when taking a calcium channel blocker, as this could result in a potentially dangerous rapid heart beat. 

Side Effects Associated With Calcium Channel Blockers

There are a number of side effects that can occur with calcium channel blockers, but they do not occur in all patients and the benefits of therapy are greater than the risk of side effects. These potential side effects include headache, constipation, dizziness, heartburn, nausea, swelling in the lower extremities, fatigue, and rashes or flushing. Side effects associated with calcium channel blockers are less likely to occur in older patients. Patients may also experience low blood sugar. If you notice any side effects, consult your doctor before stopping the medication. Stopping a medication suddenly is never a good idea. Your doctor will be able to advise you about alternatives, including lowered dosage or different medications.

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