Grapefruit Juice Dangers Q&A

What is the problem with grapefruit juice?

Dr. Talano: The problem with grapefruit juice is that it interferes with the metabolism of certain drugs in the liver. As a result of that, it potentiates the effects of these drugs. What I mean by that is normally there are many drugs that are broken down by the liver, and the use of grapefruit blocks the breakdown of the drug by the liver, and consequently the levels of this drug that are circulating are much higher. So as a result of that, you get a greater toxic effect of the high levels of that drug.

What kind of damage can that cause?

Dr. Talano: For instance, with the use of statans, drugs to lower cholesterol, it can actually cause muscle damage. As a result of the muscle damage, you can actually get kidney damage and kidney failure. So these are very toxic effects of the drugs that can actually kill you. There are other drugs, for instance, that if taken with this can cause arrhythmias of the heart. We know some of the antihistamines that were used, which are now off the market, were causing cardiac arrhythmias. As a result of that, patients who were taking these drugs with grapefruit could potentiate the effects of these drugs and cause abnormal arrhythmias of the heart.

Aren't some of the antihistamines still on the market?

Dr. Talano: Some of these drugs are still on the market, but Seldane, for instance, has been taken off the market and replaced by another drug simply because of its anti-arrhythmic effects. So these drugs, at least the real toxic ones have been recognized, and voluntarily the companies have taken them off the market.

How much is too much grapefruit juice? Should we just stop drinking it all together?

Dr. Talano: No, I don't think it's necessary to stop drinking grapefruit juice. I just think that if you are on drugs, such as the statan drugs or antihistamines, you need to just drink grapefruit juice in moderation. One glass a day is not going to kill you, but if you take four or five or six glasses a day or you're on a grapefruit juice diet, that can have a detrimental effect by potentiating the effects of these drugs.

What about eating grapefruit, is that okay?

Dr. Talano: Eating grapefruit is fine. You're going to get some of the grapefruit juice, but you will not get as much as you do from drinking the juice directly. So eating a grapefruit is fine. Eating four or five grapefruits again could be detrimental.

How potent can medications become as a result of interaction with a lot of grapefruit juice?

Dr. Talano: Quite potent. If you take a drug like Halcion, which is a sleeping drug, and you drink it with a lot of grapefruit juice or you take it with erythromycin, the Halcion is potentiated in the blood and you can have marked depression associated with it. So you may be sleeping for days by taking the drug with other medications or with grapefruit juice. So I think it's important for us physicians and also the patients to be aware of these drug interactions when taking so many drugs for so many conditions.

What is the patient's responsibility in knowing about what is potentially damaging when you mix it with medications you're taking?

Dr. Talano: I think the grapefruit interaction has been something that's been of recent interest. In fact, most of the information the patients have received has been off of the Internet. This is something that has been perpetuated and maybe a little bit overblown, but nonetheless I think people should be aware of this, especially those who are on binge diets or diets that take a heavy amount of grapefruit. As far as the patient is concerned, I think knowledge of a potential interaction is sufficient. If they're aware of it and they are aware they shouldn't be excessively drinking grapefruit juice, I think that's sufficient.

Could it be a fatal problem?

Dr. Talano: The problem with grapefruit juice is it's going to potentiate the effects of other drugs. So other drugs that normally would be metabolized by the liver are not going to be metabolized as rapidly. So they will be around the circulation for a long period of time. As a result, these drugs will affect the circulation and consequently will have toxic effects. Those are the things that can kill you, the toxic effects of the drug, whether it's an arrhythmia of the heart, muscle damage or nerve damage. Those are the things that can actually cause a person to die or cause a person's death.

Is it okay to drink grapefruit juice two to five hours after taking medications?

Dr. Talano: You can have grapefruit juice four or five hours after you take the medication. By that time, most of the drug has been absorbed and is in the process of being metabolized by the liver. So even if you drink grapefruit juice, the liver effects have already taken place, and the drug has been substantially metabolized -- except for the long-acting drugs, or those that take a long time to break down. Seldane, which is off the market now, has a long half life, and you couldn't drink grapefruit juice for maybe 10 or 12 hours. So except for those few drugs that are long-lasting, the effects can be mitigated after four or five hours.

What's your advice to patients concerning this issue?

Dr. Talano: My advice to patients on this issue is that if you like to drink grapefruit juice, continue to drink it. Just drink it in moderation and make sure it's at least four or five hours after you've taken medication. If you like to drink it with your medication, make sure it's only a small glass full and not a large amount.

Are there good effects to grapefruit?

Dr. Talano: Yes. There are some good effects with grapefruit. The flavanoids in grapefruit have a beneficial effect on the body. They actually have some anti-cancer effects. So the flavanoids are quite good and quite beneficial. I think you can see flavanoids in other foods, but again grapefruit juice is a good source of flavanoids.

This information is intended for additional research purposes only. It is not to be used as a prescription or advice from Ivanhoe Broadcast News, Inc. or any medical professional interviewed. Ivanhoe Broadcast News, Inc. assumes no responsibility for the depth or accuracy of physician statements. Procedures or medicines apply to different people and medical factors; always consult your physician on medical matters.