Q. I'd like some information on treating angina with medications. My doctor says I don't have the kind of heart problem that requires bypass surgery. I'd like to know what medicines are used to treat this condition.

A. Angina is chest pain that occurs when the heart muscle doesn't get enough oxygen. It's similar to muscle cramps caused by overuse, and usually results from narrowing of the heart's arteries, known as coronary arteries.

There are three types of medicines that help this condition, either by decreasing the heart's need for oxygen, increasing its supply, or both. These are the nitrates, beta blockers and calcium blockers.

Nitrates are the oldest and most familiar medicines for angina. They're also relatively inexpensive, and many physicians consider these the first drugs to try. Nitrates come in many forms, including pills that dissolve under your tongue and work very rapidly, pills that you swallow, long-lasting discs that you place on your gums, ointment that's slowly absorbed through the skin, long-acting skin discs, and an intravenous form that's sometimes used in patients hospitalized with angina or a heart attack.

Beta blockers are often used for angina and other conditions, such as high blood pressure, irregular heart rhythms and migraine headaches. They are also used after heart attacks to reduce your risk of another heart attack or sudden death. There are eight brands of beta blockers currently sold, each with slightly different characteristics, and more are on the way.

Calcium blockers are the newest class of drugs for angina treatment. Three are now available, with more expected soon. Calcium blockers are particularly effective for angina caused by spasms -- brief contractions -- of the coronary arteries. They are also sometimes used for treating heart failure, high blood pressure and certain kinds of irregular heart rhythms.

In choosing from all these medicines, your doctor takes several factors into mind, including cost, side effects and other medical problems you have. Depending on how well a particular medicine works for you and what side effects you have, your doctor may select another drug in its class, or a drug from another class entirely.

In addition to taking medications for angina, some other things you can do are to exercise regularly as advised by your doctor, lose weight if overweight, lower your blood cholesterol level and blood pressure if they're high, and not smoke.

One final point is that aspirin has been shown to reduce the risk of heart attacks in people with uncontrolled angina. Studies are under way to see if it helps prevent or reduce hardening of the arteries, angina and heart attacks in most people.

An informative booklet, "Understanding Angina," is available from the local affiliate of the American Heart Association, 2233 Wisconsin Ave. NW, Washington, D.C. 20007.

Q. Would you please tell me about the condition known as hypoglycemia? I understand that in many cases you can have symptoms from it even with a normal amount of sugar (glucose) in tha blood.

A. Hypoglycemia means low blood sugar. Although many people have been told they have this problem, or think they have it, experts believe this condition has been over-diagnosed and incorrectly used to explain various symptoms.

Low blood sugar can produce symptoms from lack of glucose itself, such as weakness, fatigue, headache, hunger, drowsiness or confusion, or from the body's response to this lack, such as anxiety, trembling, sweating or rapid heart beat. But the majority of people with symptoms like these do not have hypoglycemia.

There are two types of hypoglycemia -- reactive and fasting. Reactive hypoglycemia occurs after meals (in reaction to eating), while fasting hypoglycemia occurs after not eating for many hours. Fasting hypoglycemia is uncommon, but usually more serious. Its causes include tumors of the pancreas, which as a result overproduces insulin, thereby lowering your blood sugar; alcohol abuse; and, very rarely, failure of the pituitary or adrenal glands to work properly.

Reactive hypoglycemia occasionally occurs in people who have had a stomach operation and some people with mild diabetes. For otherwise healthy people, reactive hypoglycemia is probably uncommon. According to criteria of the American Diabetes Association, a diagnosis of this disorder depends on your having a blood test showing a low blood sugar level at the time you have symptoms, and your symptoms being relieved by eating.

The test most often used to see if your blood sugar level drops after eating is known as an oral glucose tolerance test. In this test, your blood sugar is measured several times after you drink a liquid glucose solution. Because this concentrated glucose drink often makes the blood sugar fall in normal people, without causing any symptoms, some experts feel the best test is measuring your blood sugar after eating a regular meal. When this test is done, few people with symptoms of hypoglycemia turn out to really have reactive hypoglycemia.

Blood sugar tests can now be done at home using chemical strips that measure glucose from a drop of blood. Your doctor might suggest trying this technique to see if your symptoms are really due to low blood sugar. If this screening test is positive, I think it's best to get further confirmation.

As you say in your question, some people believe that a slight drop in your blood sugar level, even though still in the normal range, can produce symptoms of hypoglycemia. If this is true, then what a person with that condition has is not, by definition, true hypoglycemia, but more likely a heightened sensitivity to normal variations in body function.

Treatment of true reactive hypoglycemia is dietary, and consists of frequent, low-carbohydrate, high-protein meals.