Guaifenesin for Fibromyalgia?

What can you tell me about guaifenesin as a treatment for fibromyalgia?

– November 21, 2014

Fibromyalgia is a chronic condition characterized by a generalized, aching pain. In the United States, an estimated 10 million people suffer from this disorder. Most are women of childbearing age. Symptoms include aches and stiffness in muscles, tendons (which attach muscles to bone) and ligaments (which attach bones to each other). The pain can occur in any part of the body and can be widespread or localized. Symptoms typically develop gradually and frequently come and go in cycles. Women tend to experience more widespread problems, while men more often develop localized symptoms, such as pain in a shoulder.

Guaifenesin (pronounced gwai-FEN-es-en) is an ingredient used in many cough syrups to loosen mucus in the respiratory tract. For several years, this drug has been promoted as a natural treatment for fibromyalgia by a Los Angeles physician, R. Paul St. Amand, M.D., assistant clinical professor of medicine at Los Angeles Harbor/UCLA Hospital. Dr. St. Amand claims that guaifenesin relieves fibromyalgia symptoms by ridding muscles, tendons, joints, and other tissues of harmful calcium phosphate deposits that result from defective kidney function.

However, I have found no scientific studies demonstrating that calcium phosphate deposits are a contributing factor in fibromyalgia, or that guaifenesin actually relieves symptoms. What’s more, there does not appear to be a single study in the medical literature demonstrating that guaifenesin is an effective fibromyalgia treatment. The only research I’ve seen is a yearlong, double-blinded, placebo-controlled investigation conducted by Robert M. Bennett, M.D., (now retired) professor of medicine and chairman of the Division of Arthritis and Rheumatic Diseases at Oregon Health & Science University. Dr. Bennett’s study, completed in 1996, was never published in a medical journal but the results were widely circulated. They showed no difference between guaifenesin and placebo for fibromyalgia treatment – and no significant change in symptoms or in levels of phosphates.

Guaifenesin adherents have criticized Dr. Bennett’s study as “flawed,” maintaining that participants may have used cosmetics and other topical products containing salicylates, which supposedly interfere with guaifenesin. There is no evidence for that assertion either.

Nevertheless, guaifenesin still has supporters, and some patients claim it has helped them, but it is not a therapy I advocate or recommend. Here are my recommendations for treatment of fibromyalgia.

Andrew Weil, M.D.

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