August 27 2008, 10:33 am PT | Posted in: Drugs
Hi Dr. Rassman,
This news story recently came up and I was wondering if it at all pertains to Propecia? Do fruit juices hamper the effect of the pills or does Propecia work no matter what it’s ingested with? Thanks for your time and consideration.
Taking pills? Lose the juice and take with water to ensure absorption: study
It has been known for some time that grapefruit juice can decrease the effectiveness of certain drugs. I do not believe Propecia is one of them, but if you are concerned, then simply do not take Propecia (finasteride 1mg) with grapefruit juice. The article does do a good job telling you when grapefruit juice is a problem.
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Propecia should have no interaction with grapefruit juice. Drugs with such interactions affect the cytochrome P450 liver enzymes, which are involved in drug metabolism. Finasteride does not appear to affect the cytochrome P450-linked drug metabolism enzyme system.
It has been known for a long time that grapefruit juice can increase the activity (by inhibiting cytochrome P-450) of certain drugs. This is the first study I’ve heard of that demonstrated that grapefruit juice can also decrease the absorption of certain drugs, thereby decreasing their activity.