DEAR DR. DONOHUE: My uncle, who is 76, has had really high blood pressure for several years. He takes felodipine (Plendil) and lisinopril (Prinivil) several times a day. At times his blood pressure is 160 over 104. How can he bring his pressure down? – T.N.

ANSWER: The treatment goal for high blood pressure is a reduction in pressure to less than 140/90. For people with diabetes or kidney disease, the goal is a pressure less than 130/80. Your uncle is not near either goal.

For pressure that refuses to budge, doctors can increase the dose of medicines currently being taken, devise a different combination of medicines or switch to new medicines. In addition, patients have to make some changes in their diet and lifestyle.

Your uncle takes a combination of medicines. One, Plendil, is an ACE inhibitor. It prevents the body from transforming renin, a kidney-made product, into angiotensin, a substance that causes a profound rise in blood pressure. His other medicine, Prinivil, is a calcium-channel blocker. It prevents minute quantities of calcium from entering muscle fibers that encircle arteries and causing them to contract. When they do, blood pressure rises. This is a good combination, but it’s not doing much for your uncle. There are many other combinations. A diuretic (water pill) rids the body of excessive fluid, and that brings blood pressure down. Beta blocker drugs intercept beta nerve signals that elevate pressure. Your uncle needs either an increased dose of his current medicines or a switch to completely different medicines.

Medicines are not the sole treatment for blood pressure. Your uncle ought to cut his use of salt dramatically. He should be eating more fruits and vegetables. Potassium, calcium and magnesium are three minerals that can bring down pressure. Foods rich in potassium include dried figs, baked potatoes with skins, bananas and oranges. Magnesium-rich foods include leafy green vegetables, nuts, unrefined grains and meat. For calcium, low-fat dairy products fill the bill.

The pamphlet on high blood pressure goes into detail on all aspects of causes and treatments. Readers can order a copy by writing: Dr. Donohue – No. 104, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.50 U.S./$6.50 Can. with the recipient’s printed name and address.

DEAR DR. DONOHUE: I give blood regularly and have done so for years. Does it promote health by making the body replace blood cells that have been taken? Or is the loss of blood hard on the heart and circulatory system? Do donors develop cancer more frequently? – R.R.

ANSWER: I have nothing but praise for you. Would that everyone were as generous. In the United States, more than 40,000 units of blood are used daily. A unit is a pint, about 500 ml. Only 5 percent of people eligible to give blood actually do so. You fulfill a great need. Thank you.

Giving blood doesn’t make a person healthier. It doesn’t make a person unhealthier, either. If a person’s health would be adversely affected by donating blood, the nurses or technicians drawing blood would not allow a donation.

Mind if I answer a few questions you didn’t ask? People can donate blood every 56 days. The blood count returns to normal in three or four weeks. The day of and the day after donation, it would be prudent not to engage in strenuous exertion.

DEAR DR. DONOHUE: Two years ago, my son met a darling girl. I recently learned she has bipolar disease. She has destroyed a beautiful china cabinet, a computer and dishes in fits of rage, and she has hit, bit and kicked my son. She refuses to take medicine. My husband and I are afraid she might kill him. What can be done? – L.P.

ANSWER: With bipolar disorder, a person’s mood swings from the pits of depression to the heights of wild elation. Physical assaults and fits of rage are unusual. This girl must see a mental health professional and must take medicine to restore her brain’s errant chemistry. If she won’t, have your son contact one and follow the advice given.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475.