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Felodipine and High Blood Pressure

How Does This Medication Help, and Who Can Take It?

By Marc Lallanilla

Updated December 12, 2008

(LifeWire) - Felodipine is a medication prescribed for high blood pressure, heart arrhythmia and angina (chest pain resulting from a low supply of blood to the heart muscle). Marketed by AstraZeneca Pharmaceuticals under the brand name Plendil, felodipine belongs to a class of medicines known as calcium-channel blockers. It was approved by the FDA in 1991.

Calcium-channel blockers -- sometimes called calcium antagonists -- work by reducing the uptake of calcium into the muscles of the heart and arteries. Because muscles require calcium to contract, reducing the availability of calcium relaxes arterial muscles and allows the arteries to open wider, which reduces blood pressure.

Felodipine is also available in combination with enalapril, an angiotensin-converting enzyme (ACE) inhibitor, as a treatment for high blood pressure. This combination therapy is marketed as Lexxel.

Felodipine has been studied for its use in heart failure by numerous researchers, and has been found to have no quality of life or survival benefit for that condition. Calcium-channel blockers like felodipine can also cause fluid retention, which is particularly dangerous in patients with heart failure. For patients with heart failure, most doctors prescribe other drugs like ACE inhibitors or beta blockers.

Although felodipine is generally well tolerated, side effects do occur in some patients. These may include swelling in the lower legs and feet, irregular heartbeat, headache, dizziness, upset stomach, swelling of the gums and flushing. It is not known if felodipine is safe for use by pregnant women or nursing mothers. Grapefruit and grapefruit products can interact with felodipine; therefore, patients taking felodipine are advised to avoid all grapefruit products.

There is some concern among medical experts about overdoses of calcium-channel blockers like felodipine. These overdoses are considered one of the leading causes of prescription drug deaths. Over 9,500 cases of calcium-channel blocker overdoses were reported to poison control centers in 2002. Toxic levels of calcium-channel blockers, whether brought about by intentional or accidental overdosing, can cause heart attacks, shock and sudden cardiac collapse.

Though felodipine and other calcium-channel blockers have been used to treat high blood pressure in patients with metabolic syndrome (a group of conditions associated with heart disease), research presented in 2008 finds that diuretics are less costly and more effective, especially among African-American patients.

Sources:

Bailey, David G., George K. Dresser, John H. Kreeft, Claudio Munoz, David J. Freeman, and John R. Bend. "Grapefruit-felodipine interaction: Effect of unprocessed fruit and probable active ingredients." Clinical Pharmacology & Therapeutics 68(2000): 468-77. 24 Nov. 2008. <http://www.nature.com/clpt/journal/v68/n5/abs/clpt2000126a.html>.



"Blood Pressure-Lowering Drugs." 13 Oct. 2008. American Heart Association. 24 Nov. 2008. <http://www.americanheart.org/presenter.jhtml?identifier=159>.



"Diuretics most effective blood pressure medication for people with metabolic syndrome." NIH News. 28 Jan. 2008. National Heart, Lung, and Blood Institute. 23 Nov. 2008. <http://public.nhlbi.nih.gov/newsroom/home/GetPressRelease.aspx?id=2505>.



Doyon, Suzanne. "Calcium Channel Blocker Overdose." Jan. 2000. Toxalert: Maryland Poison Center. 23 Nov. 2008. <http://www.mdpoison.com/publications/pdf/Jan00Toxalert.pdf>.



Littler, W.A. and D.J. Sheridan. "Placebo controlled trial of felodipine in patients with mild to moderate heart failure. UK Study Group." British Heart Journal 73:5(1995): 428-33. 23 Nov. 2008. <http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=483858>.


LifeWire, a part of The New York Times Company, provides original and syndicated online lifestyle content. Marc Lallanilla is a New York-based freelance writer and editor. He has written extensively on health, science, the environment, design, architecture, business, lifestyle and travel.

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