Vertigo likely not the fault of melatonin

The episodes of extreme dizziness you describe are most consistent with vertigo.

Usually the symptoms of vertigo are not this intense. More often, people with vertigo experience a sensation that the room is spinning or you are spinning in the room. Sometimes, it is just a sense of imbalance. Vertigo may be associated with nausea, vomiting and ringing in one or both ears (tinnitus).

Melatonin is considered to be a relatively safe supplement for short-term use. There are reports of balance and equilibrium problems at higher doses, usually more than 5 milligrams per day. While it's not likely that the melatonin is causing the episodic vertigo, the only way to know is to stop taking it.

When a person has recurrent episodes of vertigo, I usually suspect a disorder called benign position vertigo. In this condition, a change in head position causes sudden episodes of a spinning sensation. BPV is caused by small crystals that break loose in the canals of the inner ear and touch sensitive nerve endings inside.

Another potential cause of episodic vertigo is Meniere's disease. But Meniere's does not usually cause vertigo to occur as frequently as once a week. Also, the vertigo of Meniere's is accompanied by ringing in the ear and some hearing loss.

A rarer cause of recurrent vertigo is intermittent interruption of blood flow to the back part of the brain.

Your next step should be to talk with your doctor. If the problem is benign positional vertigo, your doctor may advise Epley maneuvers. This involves moving the head in a sequence of positions that directs the floating crystals into a part of the inner ear with fewer nerve endings.

Today's Medicine Cabinet was written by Howard LeWine, M.D., clinical instructor of medicine at Harvard Medical School and practicing internist with Harvard Vanguard Medical Associates and Brigham and Women's Hospital in Boston, Mass. For additional consumer health information, visit health.harvard.edu.