Guaifenesin protocol is an experimental, alternative treatment for fibromyalgia proposed in the 1990s by Dr. R. Paul St. Amand.

The proposed treatment involves three parts:
1. Titrating to the proper guaifenesin dosage.
2. avoiding salicylates and mint.
3. Following a low-carbohydrate diet if the patient is hypoglycemic.

Guaifenesin has not been approved by the FDA for the treatment of fibromyalgia, and the protocol has not been shown to be effective in clinical trials as of 2008. It has been adopted by many due to evidence of success.

Treatment details

Guaifenesin Dosage:
The dosage is individually determined by slowly titrating the dosage up until a worsening of symptoms is noticed and there is a decrease of the lesions that can be palpated in the muscles. Patients begin with 300 mg twice a day and increase from there. The guaifenesin should be pure guaifenesin and not a preparation including other medications.

Avoiding salicylic acid
Salicylic acid in even tiny amounts blocks guaifenesin from binding in the kidneys. It is present in many drugs such as aspirin, Salsalate, Disalcid, Anacin, and Excedrin. Plants produce salicylic acid, so herbal medications must be avoided as well as plant oils, gels and extracts in cosmetics and any product that touches the skin. These ingredients include aloe, castor oil, camphor, and mint. Any plants can be eaten, however, because the small amount of salicylic acid present in food is broken down in the digestive system and tagged with glycine by the liver before reaching the kidneys.

Treating hypoglycemia
Many symptoms of hypoglycemia (or perhaps more aptly titled Carbohydrate Intolerance) are similar to fibromyalgia, and, while leaving hypoglycemia untreated will not hinder the reversal of the disorder with guaifenesin, the symptoms will continue to plague the patient. The only treatment is a life-long avoidance of simple sugars, caffeine, starchy foods, and any other foods that cause insulin spikes.

Theory of fibromyalgia cause
This theory involves phosphate accumulation in cells that eventually reach a level to impede the ATP process, possibly caused by a kidney dysfunction or missing enzyme that prevents the removal of excess phosphates from the blood stream. This theory posits that fibromyalgia is an inherited disorder, and that phosphate build up in cells is gradual (but can be accelerated by trauma or illness). Calcium is required to buffer the excess phosphate when it enters the cells. The additional phosphate slows down the ATP process; however the excess calcium prods the cell to action. The causative mechanism in the kidneys is unknown.

The phosphate build-up theory is said to explain the myriad symptoms present in fibromyalgia and provides an underlying cause, but remains theoretical; there is no clinical evidence that the phosphate build-up theory is correct, or that Guaifenesin protocol is effective.

History
This theory arose when Dr. St. Amand noticed that patients with fibromyalgia symptoms had an increase of tartar on the teeth in the form of calcium phosphate. Crystals are also often found on urinalysis, which further points to calcium phosphate, and muscle biopsies show an increase of phosphate in the cytosol. Lesions of muscles, tendons, and ligaments can be felt by a method of palpation called mapping developed by Dr. St. Amand. These lesions are thought to be contracted cells forming a spastic area caused by an excess of calcium in the cytosol of the cells.

The treatment was discovered serendipitously when the physician found that uricosuric drugs for treating gout also coincided with relief of fibromyalgia symptoms. Guaifenesin is mildly uricosuric but, unlike standard uricosuric drugs, has almost no side-effects. Dr. St. Amand therefore began to study whether guaifenesin might relieve the symptoms of fibromyalgia while causing fewer side-effects than other uricosuric drugs had caused.

References
^ a b Bennett RM, De Garmo P, Clark SR (1996). "A Randomized, Prospective, 12 Month Study To Compare The Efficacy Of Guaifenesin Versus Placebo In The Management Of Fibromyalgia" (reprint). Arthritis and Rheumatism 39: S212. doi:10.1002/art.1780391004. http://www.myalgia.com/guaif2.htm.
Lay summary and report:
Melissa Kaplan (April 19, 2007). "Is One Placebo Better Than Another? -- The Guaifenesin Story". Chronic Neuroimmune Diseases. Fibromyalgia Network. http://www.anapsid.org/cnd/drugs/guai2.html.
^ Robert Bennett. "Speculation as to the mechanism whereby some of Dr. St. Amand's fibromyalgia patients experienced improvement while taking guaifenesin". Fibromyalgia Information Foundation. http://www.myalgia.com/Treatment/guaifspe.htm. Retrieved on 2008-01-06.
^ St. Amand, R. Paul. "A Response To The Oregon Study's Implication", Clinical Bulletin of Myofascial Therapy, Vol. 2(4) 1997. c 1997 by The Haworth Press.