Grapefruit juice can reduce the effectiveness of Viagra

By : James | Published : Monday September 5, 2011 | Posted in : Men's Health | Comments

As with all medications, Viagra, or Viagra sildenafil – sildenafil being the active ingredient in the medication – can sometimes cause side effects, and its effectiveness can be hampered when taken with other medications or substances. One example of this is Viagra and grapefruit juice, a perhaps unlikely combination but one which should be avoided if you are using the impotence medication and want it to remain effective. Grapefruit juice stops sildenafil from efficiently entering the blood stream, which renders it inactive.

When a person drinks grapefruit juice, an enzyme which is found in the small intestine wall is blocked and this has the ability to stop some medications from being completely absorbed into the blood stream. Although smaller amounts will make it through, the potency of the drug deteriorates drastically.

It isn’t just Viagra which is affected by grapefruit juice, it can also impact pain medications, antiarrhythmics, immune suppressants, intestinal medications, psychiatric medications calcium channel blockers statins and also some antihistamines. It is therefore very important for you to discuss any regular grapefruit juice consumption with a doctor or, at the very least, study in detail the patient information leaflet packaged with your medication.

The discovery that grapefruit juice could affect Viagra in this way happened by chance during research on the effects alcohol had on felodipine (a calcium blocker). It was being used as a flavouring to mask the taste of the alcohol. Results of the research showed a large amount of felodipine in the blood, which increased the side effects, which was caused by the grapefruit juice and not the alcohol, which was contrary to expectations.

Further research into the juice showed that a compound contained in the fruit called furanocoumarins was a contributing factor to the affects grapefruit juice has on certain medications. Even a measure as small as one glass of grapefruit juice can lead to serious consequences; furanocoumarins can affect the enzymes of the small intestine for up to 24 hours, so it’s not just swallowing a Viagra pill with grapefruit juice which is a problem.

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