You've probably heard that grapefruit juice shouldn't be taken with medications because a chemical quirk in the juice boosts the potency of certain drugs, increasing the risk of a dangerous overdose.
It appears that grapefruit juice impedes an enzyme that plays a key role in metabolizing some drugs. When the effect of the enzyme is derailed, more of a drug's active ingredient reaches the bloodstream.
The enzyme - known as CYP 3A4 - may also be affected by apple juice, lime juice and orange juice made from Seville oranges. These juices should also be avoided with cholesterol lowering statin drugs (such as Lipitor), selective serotonin reuptake inhibitors (such as Prozac) and, as mentioned above, drugs that manage blood pressure.
Researchers note that the effect grapefruit juice has on specific drugs may vary from patient to patient.
( taken from HSI)