Q. Where can I find out more about grapefruit interactions with medicines? I would like to know which prescription drugs are negatively affected. My pharmacist couldn’t tell me whether red yeast rice that I take to lower my cholesterol would be affected by grapefruit.
Guide to Grapefruit Interactions
A. Grapefruit or grapefruit juice can raise blood levels of lovastatin, the ingredient in red yeast rice. This might increase the risk for side effects. Atorvastatin and simvastatin are also affected, as are some blood pressure drugs and sleeping pills.
We are sending you our Guide to Grapefruit Interactions with a list of problem drugs and frequently asked questions about such incompatibilities. One point that is sometimes missed is that the grapefruit effect lasts more than 24 hours. So if you are taking your red yeast rice every day for cholesterol control, avoiding a grapefruit interaction goes beyond not taking your pills with grapefruit juice. It is essentially a ban on grapefruit (and marmalade) for as long as you are taking the supplement.
People who are taking prescription medications should ask their physicians and pharmacists whether their drugs are affected. Those who are fond of grapefruit might ask if there is an alternative that is not affected. While the cholesterol-lowering drugs simvastatin (Zocor) and atorvastatin (Lipitor) interact with grapefruit, for example, pravastatin (Pravachol) does not. In many cases, the physician may be able to find a substitute for the medication that does not pose any risk in combination with grapefruit.
