Fruited medicines  Grapefruits are high in vitamin C, potassium,
and dietary fiber.  So they’re good for us, right?    Well, in
1989 there was a study conducted to see if grapefruit juice
could mask the taste of alcohol.  Through this study,
researchers discovered that something in the grapefruit juice
caused a rise in the blood levels of a particular blood pressure
medicine.  Since this study, other research has determined that
grapefruits and grapefruit juice affect the blood levels of many
other commonly used medications.  A drug taken by mouth must get
absorbed by the intestines.  It then enters the blood stream and
travels throughout the body, affecting changes in the system. 
For example, a pill taken to lower cholesterol travels to the
liver where it will block cholesterol production.  A pill for
blood pressure may work in the kidneys, arteries or veins.
However, the drug doesn’t work indefinitely.  It is eventually
metabolized or broken down so that it can be eliminated from the
body.  The enzymes th