Why Shouldn't I Drink Grapefruit Juice With My Meds?

[Guest guest]

Q. Why Shouldn't I Drink Grapefruit Juice With My Meds?

http://bipolar.about.com/od/medications/f/faq_grapefruitj.htm?nl=1

From Kimberly Read & Marcia Purse,

Your Guide to Bipolar Disorder.

 

FREE Newsletter. Sign Up Now!

Any number of medications can apply to this question: Prozac, BuSpar,

Tegretol, Lipitor, Verapamil, Prednisone and a host of others - even Viagra!

A. The reason why grapefruit juice is a problem for people taking certain

drugs - including many psychotropic meds - is that grapefruit juice (unlike

any other citrus juice) inhibits two enzymes that are important in

metabolizing, or breaking down, these medications. When the enzymes aren't

doing their job, much more of the drug in question remains available to

enter the patient's bloodstream, and in some cases, this can have dangerous,

even toxic, effects.

For example, as much as 99% of BuSpar (Buspirone) is normally metabolized

before the drug ever enters the bloodstream. When taken in the presence of

grapefruit juice (not even at the same time), the amount of BuSpar in the

system could increase as much as 400% - a hazardous situation.

According to Graedon's Guide to Grapefruit Interactions, " The grapefruit

interaction is long-lasting. ... investigators have found that the effect is

measurable for at least 24 hours and may linger up to two days. " This could

mean that if a person drank grapefruit juice every day, there would be an

extra-strength " grapefruit effect " in his system all the time, as the effect

of yesterday's glass might still be lingering when today's glass was drunk.

Besides the ones listed above, psychotropic medications that can be affected

to a greater or lesser degree by grapefruit juice include:

Anafranil

Clozaril

Elavil

Halcion

Haldol

Luvoxx

Seroquel

Serzone

Trazodone

Valium

Versed

Zoloft

 

There are a large number of other types of medications affected by

grapefruit juice as well, including all the cholesterol-lowering statins and

even some antibiotics and birth control pills. Always read all the

literature that accompanies your new prescriptions. Just for example, on my

prescription for Zocor, buried three-quarters of the way down in the fifth

paragraph, " Cautions, " is " Talk with your doctor before including grapefruit

or grapefruit juice in your diet while you are taking this medicine. " That

doesn't seem to me to be a strong enough warning - but at least it's there.

by Marcia Purse

References:

Grapefruit and Prescription Drugs - Mix Carefully - by Mark Bloom

Putting Drug Interactions with Grapefruit Juice in Perspective - by L.

Kendall Shaw, PharmD

Using Medications Safely: Interactions Between Grapefruit Juice and

Prescription Drugs - by R. Elaine Turner and Gail C. Rampersaud

Grapefruit Juice and Medications: A Potential for Adverse Events

Grapefruit Juice Can Interact With Medicines! - by William C. Shiel, Jr, MD,

FACP, FACR

FAQ Index