QUESTION: I heard part of a talk on radio recently about drug half-life. Please elaborate. What is a half-life? - A.D.
ANSWER: The term half-life is perhaps most familiar in its reference to radioactive substances, where it means the time it takes one half of the substance's radioactivity to decay. But half-life has taken on meaning in the field of phar-macology.The half-life of a drug in the body is the time it takes for the body to get rid of half of it. It is of particular importance in prescribing, especially for older people. That's because their bodies have slower chemistries, metabolisms. Drugs tend to hang around longer and therefore have a longer effect, or accumulate more easily in them.
What this means is that doctors may take this into account in prescribing dosages for older people rather than automatically prescribing as they would for younger adults. Today, most medicines, whether over-the-counter or prescribed, have dosage instructions in two categories - children and adults. I am sure the trend in more and more drugs will be toward expanding this to include older adults.
QUESTION: All of the weight charts I've seen have small, medium and large frames listed, with different weight limits for each. How does a person know what frame he has? I heard someone say you can do it by the size of your wrists. Please tell me about it. I am trying to stick to a diet plan and need this info. - Mrs. J.V.
ANSWER: If you are right handed, wrap your right hand around your left wrist. If the thumb and middle fingers touch, you have a medium frame. If they overlap, you have a small frame. If there's a gap between, you have a large frame.
But all this frame business is a bit hokey. The figure that matters is body-fat percentage. A woman should have no more than 25 percent. Your doctor can measure body fat with calipers.
In another part of your letter, you speak of fasting. Bad idea. It hasn't worked for you and it can be dangerous. Learning sound nutrition and sensible eating habits are your answers. For a sensible plan, see the reducing report. For a copy, write Dr. Donohue/No.27, Box 19660, Irvine, CA 92713-0660, enclosing a long, stamped, self-addressed envelope and $2.
QUESTION: Since I started running, I have developed the worst case of heartburn. I am eating as I always have in the past. The only new thing is my running. Can you explain? - G.G.
ANSWER: You are not the only one with this problem. The explanation given is that while running you swallow a lot of air, which allows stomach juices to escape upward into the esophagus. Acid in the esophagus is the basis of heartburn, which, as you know, has nothing to do with the heart at all.
If this is your problem, and if antacids don't do any good, ask the doctor about a medicine that blocks stomach acid production. Ranitidine is an example of such medicine.
C) 1990 North America Syndicate Inc.