Guaifenesin, also known as glyceryl guaiacolate, is an

expectorant Mucoactive agents are a class of chemical agents that aid in the clearance of mucus or sputum from the upper and lower airways, including the lungs, bronchi, and trachea. Mucoactive drugs include expectorants, mucolytics, mucoregulators, and muco ...

medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and re ...

that aids in the elimination of

sputum Sputum is mucus that is coughed up from the lower airways (the trachea and bronchi). In medicine, sputum samples are usually used for a naked eye examination, microbiological investigation of respiratory infections and cytological investigations ...

from the

respiratory tract The respiratory tract is the subdivision of the respiratory system involved with the process of respiration in mammals. The respiratory tract is lined with respiratory epithelium as respiratory mucosa. Air is breathed in through the nose to th ...

. Chemically it is an

ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ...

guaiacol Guaiacol () is an organic compound with the formula C6H4(OH)(OCH3). It is a phenolic compound containing an methoxy functional group. Guaiacol appears as a viscous colorless oil, although aged or impure samples are often yellowish. It occurs wid ...

and

glycerine Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...

. It is often used in combination with other medications. It is taken by mouth. Side effects may include dizziness, sleepiness, skin rash, and nausea. While it has not been properly studied in pregnancy, it appears to be safe. It is believed to work by making airway secretions more liquid. Guaifenesin has been used medically since at least 1933. It is available as a

generic medication A generic drug is a pharmaceutical drug that contains the same chemical substance as a drug that was originally protected by chemical patents. Generic drugs are allowed for sale after the patents on the original drugs expire. Because the active ch ...

and

over the counter Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid prescr ...

. In 2020, it was the 324th most commonly prescribed medication in the United States, with more than 800,000 prescriptions.

Medical use

Guaifenesin is used to try to help with coughing up thick mucus and is sometimes combined with

dextromethorphan Dextromethorphan (DXM) is a medication most often used as a cough suppressant in over-the-counter cold and cough medicines. It is sold in syrup, tablet, spray, and lozenge forms. In 2022, the FDA approved a formulation of it combined with bu ...

, an

antitussive Cold medicines are a group of medications taken individually or in combination as a treatment for the symptoms of the common cold and similar conditions of the upper respiratory tract. The term encompasses a broad array of drugs, including a ...

(cough suppressant), such as in Mucinex DM or Robitussin DM. It is also combined with

ephedrine Ephedrine is a central nervous system (CNS) stimulant that is often used to prevent low blood pressure during anesthesia. It has also been used for asthma, narcolepsy, and obesity but is not the preferred treatment. It is of unclear benefit in ...

to produce Primatene and Bronkaid tablets for symptomatic relief of

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, cou ...

Side effects

Side-effects of guaifenesin include

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

vomiting Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the Human nose, nose. Vomiting can be the result of ailments like Food-poisoning, foo ...

, formation of

kidney stone Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine s ...

s, 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 Hydration may refer to: * Hydrate, a substance that contains water * Hydration enthalpy, energy released through hydrating a substance * Hydration reaction, a chemical addition reaction where a hydroxyl group and proton are added to a compound * ...

and increasing the pH of urine. Rarely, severe allergic reactions may occur, including a rash or swelling of the lips or gums, which may require urgent medical assistance. Mild

dry mouth Xerostomia, also known as dry mouth, is dryness in the mouth, which may be associated with a change in the composition of saliva, or reduced salivary flow, or have no identifiable cause. This symptom is very common and is often seen as a side eff ...

chapped lips Cheilitis is a medical condition characterized by inflammation of the lips. The inflammation may include the perioral skin (the skin around the mouth), the vermilion border, or the labial mucosa. The skin and the vermilion border are more common ...

may also occur when taking this medication. Drinking a glass of water is recommended with each dose of guaifenesin.

Pharmacology

Mechanism of action

Guaifenesin is thought to act as an expectorant by increasing the volume and reducing the viscosity of secretions in the

trachea The trachea, also known as the windpipe, is a Cartilage, cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends ...

and

bronchi A bronchus is a passage or airway in the lower respiratory tract that conducts air into the lungs. The first or primary bronchi pronounced (BRAN-KAI) to branch from the trachea at the carina are the right main bronchus and the left main bronchus. ...

. It may aid in the flow of respiratory tract secretions, allowing ciliary movement to carry the loosened secretions upward toward the

pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struc ...

. Thus, it may increase the efficiency of the

cough reflex The cough reflex occurs when stimulation of cough receptors in the respiratory tract by dust or other foreign particles produces a cough, which causes rapidly moving air which usually remove the foreign material before it reaches the lungs. This ty ...

and facilitate removal of the secretions. Guaifenesin has

muscle relaxant A muscle relaxant is a drug that affects skeletal muscle function and decreases the muscle tone. It may be used to alleviate symptoms such as muscle spasms, pain, and hyperreflexia. The term "muscle relaxant" is used to refer to two major therapeu ...

and

anticonvulsant Anticonvulsants (also known as antiepileptic drugs or recently as antiseizure drugs) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of b ...

properties and may act as an

NMDA receptor antagonist NMDA receptor antagonists are a class of drugs that work to antagonize, or inhibit the action of, the ''N''-Methyl-D-aspartate receptor (NMDAR). They are commonly used as anesthetics for animals and humans; the state of anesthesia they induce ...

History

Similar medicines derived from the guaiac tree were in use as a generic remedy by American indigenous peoples when explorers reached

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

in the 16th century. The Spanish encountered guaiacum wood "when they conquered

Santo Domingo , total_type = Total , population_density_km2 = auto , timezone = AST (UTC −4) , area_code_type = Area codes , area_code = 809, 829, 849 , postal_code_type = Postal codes , postal_code = 10100–10699 (Distrito Nacional) , websi ...

; 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 Pharmacognosy is the study of medicinal plants and other natural substances as sources of drugs. The American Society of Pharmacognosy defines pharmacognosy as "the study of the physical, chemical, biochemical, and biological properties of drug ...

'' 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 Sarsaparilla often refers to the sarsaparilla soft drink, made from Smilax plants. Sarsaparilla may also refer to: Biology *Several species of plants, of the genus ''Smilax'', including: **''Smilax ornata'', also known as Honduran or Jamaican sar ...

, which was formerly much used as an alternative in syphilis." In the US, guaifenesin was first approved by the

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

(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 received approval on 12 July 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. In 2007, Adams was acquired by

Reckitt Benckiser Reckitt Benckiser Group plc, trading as Reckitt, is a British multinational consumer goods company headquartered in Slough, England. It is a producer of health, hygiene and nutrition products. The company was formed in March 1999 by the merg ...

. The drug is sold over-the-counter by many companies, alone and in combination.

Availability

Guaifenesin is taken

by mouth Oral administration is a route of administration where a substance is taken through the mouth. Per os abbreviated to P.O. is sometimes used as a direction for medication to be taken orally. Many medications are taken orally because they are i ...

. It is available under many

brand name A brand is a name, term, design, symbol or any other feature that distinguishes one seller's good or service from those of other sellers. Brands are used in business, marketing, and advertising for recognition and, importantly, to create an ...

s, as either the lone

active ingredient An active ingredient is any ingredient that provides biologically active or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease or to affect the structure or any function of the body of humans or animals. T ...

or as one part of a

combination drug A combination drug or a fixed-dose combination (FDC) is a medicine that includes two or more active ingredients combined in a single dosage form. Terms like "combination drug" or "combination drug product" can be common shorthand for a FDC prod ...

. Drugs combined with guaifenesin in over-the-counter preparations include the cough-suppressant

analgesics An analgesic drug, also called simply an analgesic (American English), analgaesic (British English), pain reliever, or painkiller, is any member of the group of drugs used to achieve relief from pain (that is, analgesia or pain management). It i ...

such as

paracetamol Paracetamol, also known as acetaminophen, is a medication used to treat fever and mild to moderate pain. Common brand names include Tylenol and Panadol. At a standard dose, paracetamol only slightly decreases body temperature; it is inferior ...

/acetaminophen, and

decongestants A decongestant, or nasal decongestant, is a type of pharmaceutical drug that is used to relieve nasal congestion in the upper respiratory tract. The active ingredient in most decongestants is either pseudoephedrine or phenylephrine (the latter o ...

such as

pseudoephedrine Pseudoephedrine (PSE) is a sympathomimetic drug of the phenethylamine and amphetamine chemical classes. It may be used as a nasal/sinus decongestant, as a stimulant, or as a wakefulness-promoting agent in higher doses. It was first characteri ...

, or

phenylephrine Phenylephrine is a medication primarily used as a decongestant, to dilate the pupil, to increase blood pressure, and to relieve hemorrhoids. In the United States, it was previously used orally as an over-the-counter decongestant to relieve nas ...

Veterinary use

Guaifenesin's neurological properties first became known in the late 1940s. Guaifenesin is a centrally acting muscle relaxant used routinely in large-animal veterinary surgery. Guaifenesin is used in combination with, for example,

ketamine Ketamine is a dissociative anesthetic used medically for induction and maintenance of anesthesia. It is also used as a recreational drug. It is one of the safest anesthetics, as, in contrast with opiates, ether, and propofol, it suppresses ne ...

, since guaifenesin does not provide analgesia nor does it produce unconsciousness.

Research

The guaifenesin protocol was studied as a method to treat

fibromyalgia Fibromyalgia (FM) is a medical condition defined by the presence of chronic widespread pain, fatigue, waking unrefreshed, cognitive symptoms, lower abdominal pain or cramps, and depression. Other symptoms include insomnia and a general hyp ...

; a one-year double-blind study found that the treatment performs no better than placebo. Guaifenesin was studied as a possible

fertility medication Fertility medications, also known as fertility drugs, are medications which enhance reproductive fertility. For women, fertility medication is used to stimulate follicle development of the ovary. There are very few fertility medication options a ...

, working by thinning and increasing the stretchability (

spinnbarkeit Spinnbarkeit (English: spinnability), also known as fibrosity, is a biomedical rheology term which refers to the stringy or stretchy property found to varying degrees in mucus, saliva, albumen and similar viscoelastic fluids. The term is used esp ...

) of the

cervical mucus The cervix or cervix uteri (Latin, 'neck of the uterus') is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long (~1 inch) and roughly cylindrical in shape, which changes during ...

, during the few days before ovulation, thus facilitating sperm penetration. Results from a 2014 study by the Virginia Commonwealth University's Department of Pediatrics indicated that guaifenesin did not have significant impact on sputum production or clearance in upper respiratory infections. This was consistent with a 2014 study involving 378 adult and adolescent participants, which indicated guaifenesin had no significant effect as either mucolytic or expectorant compared to placebo: "Although the upper respiratory quality of life improved over the course of the study in both the uaifenesinand placebo groups, this improvement was not accompanied by changes in sputum properties".

References

External links

* * {{Portal bar , Medicine Drugs with unknown mechanisms of action Expectorants Catechol ethers Wikipedia medicine articles ready to translate Uric acid Glycerols Methoxy compounds