Doctors who prescribe vitamin B6 to carpal tunnel syndrome patients could be doing them more harm than good, a University of Michigan study indicates.

The vitamin supplements could cause serious nerve damage to patients with the painful wrist ailment, the study said.

Doctors occasionally prescribe B6 to carpal tunnel syndrome patients because limited studies have indicated the vitamin may have some therapeutic effects, said Dr. Alfred Franzblau of the University of Michigan School of Public Health.

But this is not so, Franzblau said.

"When you actually look at these studies and review them carefully, they are very, very bad," he said last week.

Franzblau said the U.S. Recommended Dietary Allowance of B6 for adults is 1.6 to 2.0 milligrams a day. Doctors are prescribing supplements of 150 milligrams to 300 milligrams a day.

Too much B6 can cause permanent nerve damage, including symptoms that mirror multiple sclerosis, experts say.

Uncovering the harmful effects of vitamin B6
Critics of megavitamin therapy often have been tolerant of the practice because it seemed to do no harm. This view was especially common in the case of water-soluble vitamins such as vitamin B6. The amount beyond that needed by your body was presumably harmless and eliminated in the urine. (Fat-soluble vitamins are stored in fat cells and remain for a longer time in your body.)

Recently abuse of vitamin B6 has been the focus of much concern. Vitamin B6 has been touted as a way to build muscles; to relieve fluid retention and other problems associated with premenstrual syndrome (PMS); and to treat kidney stones, nausea during pregnancy and a variety of chronic
pain syndromes.

Like the claims for megavitamin therapy in general, these attributes of vitamin B6 have never been verified. But we do know that excessive consumption of vitamin B6 can cause serious nerve damage.

Symptoms include unsteadiness (to the point of being unable to walk without a cane) and numbness or tingling of the feet and hands. When large doss of vitamin B6 are taken, microscopic analysis shows deterioration of nerve fibers in direct proportion to the amount of B6 ingested. Large dose4s of vitamin B6 also can alter the effects of penicillin, some medications for Parkinson's disease and certain anticonvulsants.

Discontinuing megadose therapy will reduce or eliminate most symptoms. However, adverse effects can linger for more than a year in some cases.

It is recommended that you
Avoid self-medication with large doses of any vitamins. But particularly vitamin B6. Although vitamins are a "natural" part of your diet, some can have toxic effects if the dosage is too large.
We discourage megavitamin therapy except in rare instances, when supervised by a physician.

If you take vitamin supplements in excess of 100 per cent of the daily RDA, we urge you to tell your doctor. This information can be of vital importance to your doctor in assessing your health and prescribing medications for you.

Vitamin B6
The following items are on vitamin B6 and they reinforce the fact that vit. B6 can be harmful.
Megadoses of Vitamin B6
Harmless vitamin can lead to serious nerve problems (February 1989)

"It can't hurt and it might help, so why not?" "More is better." "You can't get too much of a good thing."

Our society's casual attitude toward multivitamins has dangerous implications. Only a few generations ago, vitamin deficiency was a frequent cause of disease; today, people sometimes have health problems because they take too many vitamins.

Evidence now shows that at least one vitamin - B6 (Pyridoxine) - can cause serious harm.

Despite a daily recommended dietary allowance (RDA) of 2 or 3 milligrams of vitamin B6, tablets containing as much as 50 and 500 milligrams are readily available. People who apparently believe vitamin B6 has no side effects sometimes consume 1,000 milligrams or more each day. Such excessive dosages have recently been linked to incapacitating nerve damage, from which recovery often can take months or even years. In rare cases, the nerve damage may be permanent.