Guaifenesin INN ( /gwa?'f?n?s?n/) or guaiphenesin (former BAN), also glyceryl guaiacolate, is an expectorant drug sold over the counter and usually taken by mouth to assist the bringing up (expectoration) of phlegm from the airways in acute respiratory tract infections. Contents [hide] 1 History 2 Availability 3 Uses 4 Effect and mechanism of action 4.1 Treatment of coughing 4.2 Treatment of asthma 4.3 Treatment of gout 4.4 Treatment of fibromyalgia 4.5 Use to facilitate conception 4.6 Use by singers 5 Side-effects 6 Veterinary use 7 See also 8 References 9 External links  HistorySimilar medicines derived from the guaiac tree were in use as a generic remedy by Native Americans when explorers reached North America in the 16th century. The Spanish encountered guaiacum wood "when they conquered San Domingo; it was soon brought back to Europe, where it acquired an immense reputation in the sixteenth century as a cure for syphilis and certain other diseases..." The 1955 edition of the Textbook of Pharmacognosy states: "Guaiacum has a local stimulant action which is sometimes useful in sore throat. The resin is used in chronic gout and rheumatism, whilst the wood is an ingredient in the compound concentrated solution of sarsaparilla, which was formerly much used as an alternative in syphilis." Guaifenesin was first approved by the Food and Drug Administration (FDA) in 1952. Although previously deemed "Generally Regarded as Safe" in its original approval, the drug received a New Drug Application for the extended-release version, which won approval on July 12, 2002. Because of this, the FDA then issued letters to other manufacturers of timed-release guaifenesin to stop marketing their unapproved versions, leaving Adams Respiratory Therapeutics in control of the market. Adams was subsequently acquired by Reckitt Benckiser, based on the strength of the marketing generated by Adams' Mucinex brand.  AvailabilityGuaifenesin is sold as pills or syrups under many brand names. Single-ingredient formulations of guaifenesin are available, and it is also included in many other over-the-counter cough and cold remedy combinations (usually in conjunction with dextromethorphan and/or pseudoephedrine or phenylephrine and/or acetaminophen). Guaifenesin is a component of Mucinex, Robitussin DAC, Cheratussin DAC, Robitussin AC, Cheratussin AC, Benylin, DayQuil Mucous Control, Meltus, and Bidex 400, as well as Buckley's Cough, Mucus & Phlegm.  UsesThe principal use of guaifenesin is in the treatment of coughing, but the drug has numerous other uses, including medical, veterinary, and personal.  Effect and mechanism of actionGuaifenesin is thought to act as an expectorant by increasing the volume and reducing the viscosity of secretions in the trachea and bronchi. It also stimulates the flow of respiratory tract secretions, allowing ciliary movement to carry the loosened secretions upward toward the pharynx. Thus, it may increase the efficiency of the cough reflex and facilitate removal of the secretions; however, objective evidence for this is limited and conflicting.  Treatment of coughingA Cochrane Collaboration meta-analysis of over-the-counter medicines for acute cough in children and adults found no evidence for the effectiveness of any examined drug other than guaifenesin; evidence for guaifenesin was ambiguous. Guaifenesin is sometimes combined with dextromethorphan, an antitussive.  Treatment of asthmaGuaifenesin is claimed to be effective in the treatment of the thickened bronchial mucosa characteristic of asthma. It works by drawing water into the bronchi. The water both thins mucus and lubricates the airway, facilitating the removal of mucus by coughing. However, asthmatics should not use guaifenesin routinely.  Treatment of goutGuaifenesin is a uricosuric, increasing excretion of uric acid from the blood serum into the urine. This fact was discovered by chance, during a survey of hypouricemia in hospital inpatients. Compared to other uricosuric drugs used to treat gout, guaifenesin is relatively mild.  Treatment of fibromyalgiaBecause of its uricosuric effect, guaifenesin was chosen in the 1990s for the experimental guaifenesin protocol â€“ a treatment for fibromyalgia. Proponents of the guaifenesin protocol believe that it treats fibromyalgia by removing excess phosphate from the body. However, a consumer alert on the Fibromyalgia Network's website states that Dr. St. Amand's claims of guaifenesin's effects on fibromyalgia are groundless, and cites double-blind research by Robert Bennett, M.D., which found no significant differences between guaifenesin and a placebo in terms of any effect on fibromyalgia or its markers.. Of note, the study by Bennett was completed in 1995. Besides the small numbers (16 guaifenesin, 15 placebo) and failure to warn patients about the blocking effects of salicylates other flaws in the project have been fully discussed by St. Amand (project consultant) on website, fibromyalgiatreatment.com. Guaifenesin has not been approved by the FDA for the treatment of fibromyalgia, but no other clinical studies have been reported. The protocol has been adopted by many patients because of the anecdotal evidence of success. However, a more recent paper by Z. Zhang reported twenty-three altered cytokine/chemokine levels in the plasma of 92 women with fibromyalgia and 69 family members. Results were compared to 77 controls. Of the twenty-five tested cytokines/chemokines, 23 were abnormally elevated. Ten were lowered or normalized, 9 were raised, and five remained unchanged (all significant p levels)on guaifenesin treatment.  Feng J, Zhifang Z, Li W, Shen X, Song W, Yang C, Chang F, Longmate J, Marek C, St. Amand RP, Krontis T, Shively J, Sommer SS. Missense Mutations in the MEFV Gene Are Associated with Fibromyalgia Syndrome and Correlate with Elevated IL-beta Plasma Levels. PLosOne December 2009/  Use to facilitate conceptionGuaifenesin is widely used by women to facilitiate conception by thinning and increasing the amount of cervical mucus. Evidence concerning the effectiveness of this use is almost entirely anecdotal; the exception is a very small study without controls. One investigator regards guaifenesin as the simplest but least effective method of improving cervical mucus. Following a medical article in Czech about guaifenesin in the treatment of primary dysmenorrhea, another very small but double-blind and placebo-controlled experiment found that guaifenesin reduced primary dysmenorrhea, but the effect was not significant.  Use by singersOpera singers sometimes refer to guaifenesin as the "wonder drug" for its ability to promote secondary mucosal secretion in the respiratory system. Secondary mucus is the thinner, lubricating mucus that occurs on the vocal folds naturally when they are healthy and well hydrated. Singers use guaifenesin to improve the state of their vocal folds in extremes of humidity (very humid or very dry), after flying long distances, and during mild allergies.  Side-effectsConsumption of guaifenesin in above-normal quantities has the potential to cause side-effects. Known side-effects include nausea, vomiting, and (rarely) the formation of kidney stones of uric acid (uric acid nephrolithiasis). Nausea and vomiting can be reduced by taking guaifenesin with meals. The risk of forming kidney stones can be reduced by maintaining good hydration and increasing the pH of urine (see Uric acid nephrolithiasis). Rarely, severe allergic reactions may occur, including a rash or swelling of the lips or face, which may require urgent medical assistance. Mild dry mouth or chapped lips may also occur when taking this medication. Drinking a glass of water is recommended each time one takes guaifenesin. Water helps to reduce dry mouth, chapped lips, and the risk of kidney stones, and increases the effectiveness of the drug in hydrating mucus.  Veterinary useGuaifenesin's neurological properties first became known in the late 1940s, and it is widely used in veterinary medicine to induce and maintain anesthesia in horses and llamas. In contrast to other propanediol drugs used for this purpose, guaifenesin has less hemolytic activity (i.e., less destruction of red blood cells) and is more soluble in water.