How come you can not drink grapefruit juice with some medications?

Answer 1

Karch, an expert on drug interactions, explains that grapefruit juice is one of the foods most likely to cause problems with drugs, because it is metabolized by the same enzyme in the liver that breaks down many drugs. The cytochrome P-450 3A4 enzyme breaks down grapefruit juice into useful components for body, just like it breaks down dozens of medications. Karch says when the system is overloaded, the grapefruit juice can “swamp” the system, keeping the liver busy and blocking it from breaking down drugs and other substances.

Drugs that use the same pathway and interact with grapefruit juice target some of the most common health problems doctors see today. The list consists of more than 50 medications, including some drugs used to treat high cholesterol, depression, high blood pressure, cancer, depression, pain, impotence, and allergies.

Answer 2

Certain chemicals in grapefruit juice interfere with the normal breakdown of medications, so the effective dose can be much higher. Scientists don't know exactly how it happens, but it is well documented.

Here's a clip:
"Grapefruit juice provides many nutrients, such as vitamin C and lycopene. But chemicals in grapefruit interfere with the enzymes that break down (metabolize) certain drugs in your digestive system. This can result in excessively high levels of these drugs in your blood and an increased risk of serious side effects.

The exact chemicals in grapefruit juice that cause this interaction aren't known. "

See the rest of the link for more info, including a list of meds that are known to be problematic: http://www.mayoclinic.com/health/food-and-nutrition/AN00413

Answer 3

Because the grapefruit juice interferes with the same enzymes that break down same medications, so you wind up with a backup of medication in your system because the receptors are busy dealing with the grapefruit

Answer 4

Because it binds some of the medication so they cannot be absorbed by the body and utilized. This is especially true w/ Lipitor, as it binds it and it will no longer block cholesterol being absorbed.

Answer 5

It's a highly acidic fruit which can breakdown the medication faster than it should be disintegrating, and could potentially give you stomach problems.