Guaifenesin

Guaifenesin

Systematic (IUPAC) name
(RS)-3-(2-methoxyphenoxy)propane-1,2-diol
Clinical data
Trade names	Mucinex
AHFS/Drugs.com	monograph
MedlinePlus	a682494
Licence data	US FDA:link
Pregnancy cat.	C (US)
Legal status	OTC (US, CA)
Routes	Oral (PO)
Pharmacokinetic data
Metabolism	Renal
Half-life	2.88 hours[1]
Identifiers
CAS number	93-14-1 Y
ATC code	R05CA03 QM03BX90
PubChem	CID 3516
DrugBank	APRD01005
ChemSpider	3396 Y
UNII	495W7451VQ Y
KEGG	D00337 Y
ChEMBL	CHEMBL980 Y
Chemical data
Formula	C10H14O4
Mol. mass	198.216 g/mol
SMILES	eMolecules & PubChem
InChI InChI=1S/C10H14O4/c1-13-9-4-2-3-5-10(9)14-7-8(12)6-11/h2-5,8,11-12H,6-7H2,1H3 Y Key:HSRJKNPTNIJEKV-UHFFFAOYSA-N Y
N(what is this?)  (verify)

Guaifenesin INN ( /ɡwaɪˈfɛnɨsɪn/) or guaiphenesin (former BAN), also glyceryl guaiacolate,^[2] 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.

History

Similar 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..." ^[3]
The 1955 edition of the Textbook of Pharmacognosy also says that:
"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 alterative in syphilis."^[3]
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. ^{[4] [5]}

Availability

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 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.

Uses

The 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 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.^[6] 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 coughing

A 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.^[7] Guaifenesin is sometimes combined with dextromethorphan, an antitussive.

Treatment of asthma

Guaifenesin is claimed to be effective in the treatment of the thickened bronchial mucosa characteristic of asthma.^{[citation needed]} 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 gout

Guaifenesin is a uricosuric, increasing excretion of uric acid from the blood serum into the urine.^[8] This fact was discovered by chance, during a survey of hypouricemia in hospital inpatients.^[9] Compared to other uricosuric drugs used to treat gout, guaifenesin is relatively mild.^{[citation needed]}

Treatment of fibromyalgia

Because of its uricosuric effect, guaifenesin was chosen in the 1990s for the experimental guaifenesin protocol – 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 ^[10] 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.

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 anecdotal evidence of success.^[11]

Use to facilitate conception

Guaifenesin is widely used by women to facilitiate conception by thinning and increasing the amount of cervical mucus.^[12] Evidence concerning the effectiveness of this use is almost entirely anecdotal; the exception^[13] is a very small study without controls. One investigator^[14] 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,^[15] another very small but double-blind and placebo-controlled experiment^[16] found that guaifenesin reduced primary dysmenorrhea, but the effect was not significant.

Use by singers

Opera 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.^[17]

Other uses

Guaifenesin also has other known physiological effects, including an analgesic effect that is related to its action as a skeletal muscle relaxant, and possible inhibition of platelet aggregation.^{[citation needed]}

Side effects

Consumption 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).^[18] Nausea and vomiting can be reduced by taking guaifenesin with meals.^[2] 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.^[19] 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 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^[20][21] and llamas.^[22] 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.^{[citation needed]}

See also

• Guaiacol
• pseudovent

References

1. ^ 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. http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8218524. 
2. ^ ^{a b} "Guaifenesin". Drugs.com. http://www.drugs.com/ppa/guaifenesin-glyceryl-guaiacolate.html. Retrieved 2008-10-29. 
3. ^ ^{a b} Wallis, Thomas (1955). Textbook of Pharmacognosy. 
4. ^ "Announcements RB Press release - 10/12/2007". http://www.rb.com/site/RKBR/Templates/MediaInvestorsGeneral2.aspx?pageid=262&cc=GB. Retrieved 16 November 2010. 
5. ^ Goldstein, Jacob (25 May 2007). "FDA Bumps Phlegm-Fighters From Market". The Wall Street Journal. http://blogs.wsj.com/health/2007/05/25/fda-bumps-phlegm-fighters-from-market/. Retrieved 16 November 2010. 
6. ^ Gutierrez, K. (2007). Pharmacotherapeutics: Clinical Reasoning in Primary Care. W.B. Saunders Co.
7. ^ Smith SM, Schroeder K, Fahey T (2008). Smith, Susan M. ed. "Over-the-counter medications for acute cough in children and adults in ambulatory settings". Cochrane Database Syst Rev (1): CD001831. doi:10.1002/14651858.CD001831.pub3. PMID 18253996. 
8. ^ Ramsdell CM, Postlethwaite AE, Kelley WN (March 1974). "Uricosuric effect of glyceryl guaiacolate". The Journal of rheumatology 1 (1): 114–6. PMID 4617771. 
9. ^ Ramsdell CM, Kelley WN (February 1973). "The clinical significance of hypouricemia". Annals of internal medicine 78 (2): 239–42. PMID 4683752. 
10. ^ http://www.fmnetnews.com/resources-alert-product6.php
11. ^ Zhang Z, Cherryholmes G, Mao A, Marek C, Longmate J, Kalos M, St. Amand RP, Shively JE. High Plasma Levels of MCP-1 and Eotaxin Provide Evidence for an Immunological Basis of Fibromyalgia. J. of Experimental Biology and Medicine; June 2008
12. ^ Weschler, Toni (2002). Taking Charge of Your Fertility (Revised ed.). New York: HarperCollins. p. 52. ISBN 0-06-093764-5. 
13. ^ Check JH, Adelson HG, Wu CH (1982). "Improvement of cervical factor with guaifenesin". Fertil. Steril. 37 (5): 707–8. PMID 6896190. 
14. ^ Check JH (2006). "Diagnosis and treatment of cervical mucus abnormalities". Clin Exp Obstet Gynecol 33 (3): 140–2. PMID 17089574. 
15. ^ Kraus I, Horský A, Presl J, et al. (September 1981). "[Combined treatment of idiopathic dysmenorrhoea by acetylsalicylic acid and guaiphenezine (author's transl)]" (in Czech). Cesk Gynekol 46 (8): 601–5. PMID 6118209. 
16. ^ Marsden JS, Strickland CD, Clements TL (2004). "Guaifenesin as a treatment for primary dysmenorrhea". J Am Board Fam Pract 17 (4): 240–6. doi:10.3122/jabfm.17.4.240. PMID 15243011. http://www.jabfm.org/cgi/pmidlookup?view=long&pmid=15243011. 
17. ^ http://www.prohealth.com/library/showarticle.cfm?id=7244&t=CFIDS_FM
18. ^ 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. 
19. ^ Guaifenesin http://www.nlm.nih.gov/medlineplus/druginfo/meds/a682494.html
20. ^ McGrath CJ (July 1984). "Anesthesia for cesarean section in large animals". Mod Vet Pract 65 (7): 522–4. PMID 6749119. 
21. ^ 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. 
22. ^ 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. 

External links

• Guaifenesin at nlm.nih.gov
• MedlinePlus DrugInfo meds-a682494
• RxList site giving some properties
• Information from MedicineNet.com