|Systematic (IUPAC) name|
|Licence data||US FDA:|
|Pregnancy cat.||C (US)|
|Legal status||Over the counter (Behind the Counter when combined with pseudoephedrine)|
|ATC code||R05 QM03|
|Mol. mass||198.216 g/mol|
| (what is this?)
Guaifenesin INN (pron.: //) or guaiphenesin (former BAN), also glyceryl guaiacolate, is an expectorant drug sold over the counter and usually taken orally to assist the bringing up (expectoration) of phlegm from the airways in acute respiratory tract infections.
A closely related compound is guaietolin (3-(2-ethoxyphenoxy)propane-1,2-diol) which is used for similar purposes.
Similar medicines derived from the guaiac tree were in use as a generic remedy by American Indians when explorers reached North America in the 16th century. The Spanish encountered guaiacum wood "when they conquered Santo 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.
||The examples and perspective in this section deal primarily with North America and do not represent a worldwide view of the subject. (February 2012)|
Guaifenesin 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 acetaminophen and/or ephedrine/pseudoephedrine or phenylephrine). Guaifenesin is a component of Mucinex, Robitussin DAC, Cheratussin DAC, Robitussin AC, Cheratussin AC, Benylin, Buckley's, DayQuil Mucus Control, Meltus, and Bidex 400, as well as Buckley's Cough, Mucus & Phlegm, Walmart Equate Tussin, and Cough Be Gone.
Medical Uses 
The principal use of guaifenesin is in the treatment of coughing. A Cochrane Collaboration meta-analysis of over-the-counter medicines for acute cough in children and adults concluded that there was not enough high quality clinical data to prove or disprove the effectiveness of any examined drug including guaifenesin. Guaifenesin is sometimes combined with dextromethorphan, an antitussive.
Other Uses 
Guaifenesin 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. The guaifensen protocol is an attempt to market guaifenesin as a purported treatment for fibromyalgia.  Guaifenesin has not been approved by the FDA for the treatment of fibromyalgia. Based on a small, non-blinded study , Guaifenesin has been promoted to facilitiate conception, by thinning and increasing cervical mucus, during the few days before ovulation.
Mechanism of action 
Guaifenesin 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.
Side-effects of guaifenesin include nausea, vomiting, formation of kidney stones , diarrhea, and constipation. Nausea and vomiting can be reduced by taking guaifenesin with meals. The risk of forming kidney stones during prolonged use can be reduced by maintaining good hydration and increasing the pH of urine. 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.
Guaifenesin "increases the analgesic effect of paracetamol (acetaminophen) and aspirin, increases the sedative effects of alcohol, tranquilisers, sleep-pills and total anesthetics. Guaifenesin increases the effects of medication that decrease muscle tone. Guaifenesin effects are increased by lithium and magnesium."
Veterinary use 
Guaifenesin'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. This can be mostly explained by its amplifying effect on sedatives and total anestetics so that lower total doses can be used.
See also 
- Aluri JB, Stavchansky S (1993). "Determination of guaifenesin in human plasma by liquid chromatography in the presence of pseudoephedrine". J Pharm Biomed Anal 11 (9): 803–8. doi:10.1016/0731-7085(93)80072-9. PMID 8218524.
- "Guaifenesin". Drugs.com. Retrieved 2008-10-29.
- Wallis, Thomas (1955). Textbook of Pharmacognosy. Unknown parameter
- "Announcements RB Press release - 10/12/2007". Retrieved 16 November 2010.
- Goldstein, Jacob (25 May 2007). "FDA Bumps Phlegm-Fighters From Market". The Wall Street Journal. Retrieved 16 November 2010.
- Smith SM, Schroeder K, Fahey T (2008). "Over-the-counter medications for acute cough in children and adults in ambulatory settings". In Smith, Susan M. Cochrane Database Syst Rev (1): CD001831. doi:10.1002/14651858.CD001831.pub3. PMID 18253996.
- Ramsdell CM, Postlethwaite AE, Kelley WN (March 1974). "Uricosuric effect of glyceryl guaiacolate". The Journal of rheumatology 1 (1): 114–6. PMID 4617771.
- Ramsdell CM, Kelley WN (February 1973). "The clinical significance of hypouricemia". Annals of internal medicine 78 (2): 239–42. PMID 4683752.
- "Consumer Alert — Guaifenesin for Fibromyalgia". Fmnetnews.com. Retrieved 2012-01-04.
- 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 (10): S212. doi:10.1002/art.1780391402.
- Check JH, Adelson HG, Wu C-H. "Improvement of cervical factor with guaifenesin". Fertility and Sterility. 1982;37:5.
- Weschler, Toni (2002). Taking Charge of Your Fertility (Revised ed.). New York: HarperCollins. p. 52. ISBN 0-06-093764-5.
- Gutierrez, K. (2007). Pharmacotherapeutics: Clinical Reasoning in Primary Care. W.B. Saunders Co.
- Bennett S, Hoffman N, Monga M (December 2004). "Ephedrine- and guaifenesin-induced nephrolithiasis". J Altern Complement Med 10 (6): 967–9. doi:10.1089/acm.2004.10.967. PMID 15673990.
- Guaifenesin Side Effects http://www.drugs.com/sfx/guaifenesin-side-effects.html
- Guaifenesin http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682494.html
- "STOPTUSSIN". Teva. Retrieved 2013-01-28.
- McGrath CJ (July 1984). "Anesthesia for cesarean section in large animals". Mod Vet Pract 65 (7): 522–4. PMID 6749119.
- Lin HC, Wallace SS, Robbins RL, Harrison IW, Thurmon JC (January 1994). "A case report on the use of guaifenesin-ketamine-xylazine anesthesia for equine dystocia". Cornell Vet 84 (1): 61–6. PMID 8313710.
- Hopkins SM, Althouse GC, Jackson LL, Evans LE (October 1991). "Surgical treatment of uterine torsion in a llama (Lama glama)". Cornell Vet 81 (4): 425–8. PMID 1954745.
- Guaifenesin at nlm.nih.gov
- MedlinePlus DrugInfo meds-a682494
- Mucinex Side Effects
- RxList site giving some properties
- Information from MedicineNet.com