Dear Dr. Donohue: I am 85 and in good health. For the past several years, I have been taking levothyroxine (Synthroid, thyroid hormone) for an underactive thyroid gland. The problem is, I am losing weight and have insomnia. I read that blood tests for thyroid hormone are not always accurate. My daughter says I should stop the drug, and maybe I could gain some weight and get to sleep. What is your opinion?

M.S.

Dear M.S.: Perhaps your thyroid medicine is responsible for your weight loss and insomnia. I'm sure your doctor would approve of you going off it for a few weeks to see what happens.

If you begin to gain weight and get to sleep, you've hit a bases-loaded home run.

Symptoms of an underactive thyroid gland include fatigue, dry skin, weight gain in the face of a poor appetite, constipation, hair loss, a slow heartbeat, feeling cold while those around you are comfortably warm and a disruption of menstrual periods in menstruating women.

Testing for hypothyroidism (an underactive thyroid gland) involves taking blood to check the level of TSH, thyroid stimulating hormone. The pituitary gland at the base of the brain makes TSH.

It does what it says it does. It stimulates the thyroid gland in the neck to make thyroid hormone. If the thyroid gland is not working, the levels of TSH rise in an attempt to jump-start the gland. A high TSH indicates a low output of thyroid hormone.

TSH is a reliable test. It has a sensitivity of 90 percent. After you are off your medicine for some weeks, you can be retested.

From The Detroit News: http://www.detroitnews.com/article/20120726/OPINION03/207260314#ixzz22ElddIL1