DEAR DR. DONOHUE: I have had severe high blood pressure for many years. I have tried all the medicines you can think of. I am 62 and have had one ministroke. I’m not looking for another. I used to weigh 235 pounds. I lost 100 pounds. I watch my salt. I have tried everything. My family has a history of high blood pressure. Can you recommend anything? – F.

ANSWER: Blood pressure that doesn’t drop by making life changes (weight loss and diet) or by taking three or four blood pressure medicines is called resistant high blood pressure (hypertension). Your weight loss is admirable. It should have reduced your pressure. Watching your salt intake is also important. That entails more than not using the salt shaker. It requires you to carefully look for the salt content (listed as sodium or sodium chloride) of all your foods. Commercial soups, frozen dinners, many canned goods and luncheon meats often have a high salt content. Your diet should be one of fruits, vegetables, whole grains (unrefined wheat, barley, rye and oats) and one where meat and fats are eaten sparingly. Increase foods with lots of potassium in them: tomatoes, potatoes, prunes, lima beans, kidney beans, navy beans, bananas, oranges and orange juice, spinach, peaches, cantaloupe and broccoli. Potassium lowers blood pressure.

Exercise for 30 minutes every day. Get your doctor’s approval first, and start out modestly. Brisk walking is fine.

For resistant high blood pressure, your doctor has to look for the less-common causes of it. Sleep apnea (loud snoring with pauses when there is no breathing), adrenal gland tumors, Cushing’s syndrome, narrowed kidney arteries and rare tumors such as pheochromocytoma are cases in point.

Go over your medicines. Some medicines raise pressure. Nonsteroidal anti-inflammatory drugs are an example – Aleve, Advil, Motrin, Aspirin and other NSAIDs. Don’t drink more than two alcohol drinks a day.

More than 30 blood pressure medicines are on the market. I bet you haven’t tried all 30 or combinations of them. Some brands come with two medicines in one pill, easing the burden of pill-taking. A new medicine, one completely different from all other medicines, is now available. It is Tekturna. Something must be done for you pressure.

The booklet on high blood pressure gives the story of this very common malady. To receive a copy, write: Dr. Donohue – No. 104, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Allow four weeks for delivery.

DEAR DR. DONOHUE: At age 3 or 4, my niece took a butcher knife away from my great-nephew. He was on his way upstairs to kill his older brother. He is now 9 or 10 and continues to threaten his brother (no knives). He can be very belligerent, disruptive and unruly. Then, the next minute, he is the most loving, caring and polite child. He is loved, disciplined and cared for. He is very smart in school. He has seen school counselors, psychologists and medical doctors, and is on medication. I think he needs to see a pediatric psychiatrist, if there is such a person. Please help us. There must be other children like him. – J.D.

ANSWER: Child psychiatrists are found everywhere, and your great-nephew would benefit from seeing one. If he’s on medicine, I assume he is seeing such a doctor. If he’s not making any progress, he should see another.

DEAR DR. DONOHUE: Please explain mitochondria. So few have heard of it. – D.S.

ANSWER: Every body cell has mitochondria (MY-toe-CON-dree-uh), small, cigar-shaped structures that provide energy for the cell. They are body cells’ batteries.

Many diseases feature mitochondria malfunction. Usually those illnesses affect the nervous system or the muscular system, including heart muscle. I hate to leave you up in the air about this, but I can’t go further without knowing the name of your mitochondrial illness or your symptoms. If you’ll send me that information, I’ll try to oblige you.

DEAR DR. DONOHUE: I have never seen the topic of colitis in your column. I have microscopic colitis and would like more information on it. Is there a cure? I pretty much have to stay home because of it. Is it stopping me from getting all the nutritional value from food? – B.M.

ANSWER: “Colitis” means colon inflammation. The colon is the same thing as the large bowel, the last 4 to 5 feet of the digestive tract. The colon is the place where most of the fluid of undigested food is returned to the body. Food absorption takes place in the small intestine. If you’re not losing weight, you are meeting your nutritional needs.

Ulcerative colitis, Crohn’s disease and many, many intestinal infections are the chief causes of colitis. “Colitis” is a word that shouldn’t stand by itself. It needs another word to signify the kind of colitis.

Microscopic colitis is a newcomer to the colitis family, and it is subdivided into collagenous colitis and lymphocytic colitis. It’s called microscopic because only a microscopic exam of a colon biopsy can prove the diagnosis. Collagenous colitis is primarily a female condition in which bands of collagen, the body’s support tissue, are found beneath the colon lining. Its chief sign is watery diarrhea. Budesonide (a cortisone medicine), Lomotil or sulfasalazine usually can keep it in check. In lymphocytic colitis, lymphocytes (one of the white blood cell varieties) infiltrate the colon to cause the same problem — diarrhea. The same medicines are used for it. It, however, can be complicated by celiac disease, which requires abstaining from wheat, barley and rye grains.

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. Readers may also order health newsletters from www.rbmamall.com.