Why does grapefruit juice have an impact on drugs?

Eating grapefruit or drinking grapefruit juice can cause interactions with some medications - but what kind of affect does grapefruit have?

By James Lloyd

Asked by: Len Baker, Leicester

Grapefruit juice is widely regarded as a healthy, all-natural drink rich in vitamins C and A. But researchers have discovered that grapefruit juice affects the action of a human enzyme called CYP3A4, boosting the power of some drugs to potentially dangerous levels. Over 40 drugs are now known to be affected, including some used for treating blood pressure.

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