Grapefruit Juice and Medication

How does grapefruit juice affect medicines?

Grapefruit juice contains chemicals that can cause problems with enzymes that break down certain types of medicines in your intestines. When a medicine does not get broken down properly in the intestines, you can end up with too much medicine in your blood. Having too much medicine in your blood increases your chances of having serious side effects.

Which medicines are affected by grapefruit juice?

Most medicines are not affected by grapefruit juice. But more than 50 medicines are affected by grapefruit juice. These include medicines for:

• Abnormal heart rhythm.
• Allergies.
• Anxiety.
• Asthma.
• Blood clots.
• Cancer.
• Cough.
• Depression.
• Emphysema.
• Epilepsy.
• Erectile dysfunction.
• Heart attack or heart disease.
• High blood pressure.
• High cholesterol.
• HIV.
• Infection.
• Pain.
• Enlarged prostate.
• Stroke.

Not all medicines for the health problems listed above are affected by grapefruit juice. Ask your doctor how your medicines are affected by grapefruit juice and if you need to make any changes to avoid problems.

Is grapefruit juice safe for me?

If you regularly drink grapefruit juice, ask your doctor or pharmacist if any of your medicines are affected by grapefruit juice. If your medicine is making you feel sick or is causing unusual or uncomfortable side effects, talk to your doctor.

All new medicines are tested for problems caused by grapefruit juice before they are approved by the Food and Drug Administration (FDA). Medicines that are affected by grapefruit juice must have warnings in their patient information sheets. When you pick up a new medicine, your pharmacist will talk to you or give you written information about foods to avoid while taking your medicine. Some medicines may also have warnings on the “food-drug interactions” section of the bottle label.

In general, the more grapefruit juice you have, the greater the possible effects. ¹ It has been shown that even one glass of grapefruit juice—at any time of the day—is enough to cause certain medicines to work differently than they are supposed to. ² Sometimes the effects of one glass of juice can last up to 3 days.

In most cases, you may be able to have a glass of grapefruit juice without problems. Ask your doctor or pharmacist how much is safe for you.

What can happen if grapefruit juice affects my medicine?

The problems you may have from taking medicines that interact with grapefruit juice depend on the kind of medicine you are taking. Some problems are mild, while others are more serious. In general, older people are more likely than younger people to develop serious problems.

For example, if you are taking a medicine for high blood pressure, you may develop dangerously low blood pressure. If you are taking a medicine for high cholesterol, you may develop muscle breakdown problems or liver failure.

For more specific information on the kinds of health problems you could have if you drink grapefruit juice while taking a certain medicine, talk to your doctor or pharmacist.

How can I prevent problems?

You can take steps to avoid problems with grapefruit juice and your medicine.

• Before you take any medicine, ask your doctor or pharmacist if you can safely drink grapefruit juice.
• Read the labels on foods and natural health products to make sure they do not contain grapefruit, grapefruit juice, or grapefruit extract. You may also want to avoid Seville oranges (which are sometimes used in marmalade but not in orange juice), pomelos, and tangelos, because some studies have shown that they can also cause problems. ³
• Always read the warning labels for any medicine you are taking. If you have questions, ask your doctor or pharmacist.
• Tell your doctor if you are having unusual or uncomfortable side effects from your medicine.
• Tell your doctor and other health professionals about all the medicines you are taking, both prescription and over-the-counter.

Coffee: Does it offer health benefits?

Q:

I’m confused. Is coffee good or bad for me?

A:

Coffee has a long history of being blamed for many ills — from the humorous, “It will stunt your growth” to the not-so-humorous claim that it causes heart disease and cancer. But some recent research indicates that coffee may not be so bad after all. So which is it — good or bad for your health? The best answer may be: It doesn’t seem to hurt and it may help.

To get an idea of where the confusion comes from, consider two recent studies. A study of 128,000 men and women showed no increase in the risk of heart disease from drinking filtered coffee. The findings of the study — which published in May 2006 in the journal “Circulation” — indicated that it didn’t matter how much coffee participants drank.

Another study of 4,000 coffee drinkers published in March 2006 in the “Journal of the American Medical Association” found that two or more cups of coffee a day can increase the risk of heart disease in people with a specific — and fairly common — genetic mutation that slows the breakdown of caffeine in the body.

The design of a study can have some effect on the interpretation of results, which may be another reason for the different conclusions. Overall, given the large number of participants in the study that showed no risks from drinking coffee, it would be reasonable to conclude that coffee poses little or no threat to health.

But this doesn’t mean you should disregard the old maxim, “Everything in moderation.” Although coffee may not be harmful, other beverages such as milk and juice contain important nutrients that coffee does not.

Regarding other health effects of coffee, some evidence suggests that drinking coffee may protect against type 2 diabetes and colon cancer. But there is much more evidence of a protective effect from fruits, vegetables and whole grains than from coffee. So don’t be afraid to enjoy your coffee as part of a healthy diet that includes a wide variety of foods.