Q: Four years ago, a friend of mine who has fibromyalgia was referred to a physician in Mexicalli, Mexico. He gave her a prescription for capsules that she has taken every day since. Today, she is totally free of pain. Are you familiar with this Mexican medication? 

A: I don't know what ingredients are in the mystery medicine your friend is taking. If the medication is a prescription that can be filled in U.S. pharmacies, the ingredients should be appear on the package label or insert. If the ingredients aren't listed she should ask the pharmacist. Dispensing a medication without revealing its contents is unethical, and taking such a medication is unwise.

During my years at Mayo Clinic, I saw several patients who had received Mexican medication with undisclosed ingredients. But the drugs' side effects (round face, obesity of the trunk, easy bruising) made it obvious to me what they contained – large doses of cortisone or a cortisone derivative. Cortisone is a powerful medication that can be very useful in arthritis treatment, but its use and risk of side effects have to be evaluated carefully. Taking it unknowingly, particularly in doses larger than necessary, can lead to potentially dangerous side effects.

Another ingredient that has been found in some of these unlabeled capsules is Butazolidin, a potent anti-inflammatory and pain reliever. Because of its associated side effects, however, particularly aplastic anemia, Butazolidin is no longer available in this country.

Doyt Conn. MD, Rheumatologist