Calcium channel blockers (CCBs) , also referred to as calcium antagonists are prescribed to manage high blood pressure, irregular heartbeats and chest pain. The National Institute of Health (NIH) says CCBs stop calcium from entering the muscle cells of the heart and blood vessels. This prompts the blood vessels to relax and lowers blood pressure. CCBs have also been shown to help prevent and treat the symptoms of angina (chest pain) and help manage certain heart rhythm problems. Calcium channel blockers are available only by prescription. They exist in both short-acting and long-acting (time-released) forms. People who take CCBs should be aware of its interaction with grapefruit products. The Canadian Medical Association says grapefruit juice largely affects the intestine.
Grapefruit
Grapefruit juice contains a number of nutrients including vitamin C and lycopene but its chemicals can disrupt the mechanics of the enzymes that break down certain calcium channel blockers in the digestive system.
According to the Mayo Clinic, both grapefruits and grapefruit juice interact with CCBs such as Calan, Procardia, Nifedipine, and Verapamil. These CCBs should not be taken with grapefruit products because they alter the way your body metabolizes the medication.
Physical Effects
The livers diminished ability to eliminate CCBs permits the medication to accumulate in your body. This can lead to extremely high levels of CCBs in the blood and an increased risk of potentially harmful side effects. These include constipation, fatigue, palpitations, feeling lightheaded and possible rashes. In some cases headaches and flushing (sudden reddening of the face and neck) may occur.
Orthostatic Hypotension
According to website USPharmacist.com, you should refrain from drinking large amounts of grapefruit juice concurrently with any calcium antagonist. Otherwise, you may be at a higher risk of orthostatic hypotension (low blood pressure occurring when standing up) that may cause dizziness and fainting. Symptoms may also include chest pain and difficulty holding urine.
Seville Oranges
Seville oranges, which are used primarily for making marmalade, can affect the same enzyme as grapefruit does and therefore may interact in a similar fashion with calcium channel blockers.
The interaction effects of grapefruit juice and seville oranges may vary from person to person. It is generally recommended that patients stop consuming these products approximately three days prior to taking calcium channel blockers.
