Guaifenesin 1% oral solution
Guaifenesin possesses a storied history, having been originally formally approved by the US FDA in 1952 and continues to be one of very few - if not perhaps the only drug that is readily available and used as an expectorant [F4525].
Safety information for pregnancy and breastfeeding
Pregnancy
Breastfeeding
Always consult your doctor or midwife before taking any medicine during pregnancy or while breastfeeding. Source: DrugBank (CC BY-NC 4.0).
Official documents, adverse reaction reporting, and safety monitoring
Report a side effect
Submit a Yellow Card report to the MHRA
Official medicine documents
Safety monitoring data
Yellow Card reports
The MHRA Yellow Card scheme collects reports of suspected side effects from healthcare professionals and patients. View the Drug Analysis Profile (iDAP) for real-world adverse reaction data.
View Drug Analysis Profile
Browse all Drug Analysis Profiles A–Z
Browse all iDAP reports
Interactive Drug Analysis Profiles for all medicines
Report a side effect
Submit a Yellow Card report to the MHRA
Data from the MHRA Yellow Card scheme. A reported reaction does not necessarily mean the medicine caused it. Contains public sector information licensed under the Open Government Licence v3.0.
EudraVigilance
The European Medicines Agency (EMA) collects suspected adverse reaction reports from across the EU/EEA through the EudraVigilance system. Search for safety data on this medicine.
View EudraVigilance report
Suspected adverse reactions reported for Guaifenesin
About EudraVigilance
Learn about EU pharmacovigilance and safety monitoring
EudraVigilance data is published by the European Medicines Agency (EMA). A suspected adverse reaction is not necessarily caused by the medicine.
1 branded products available
WHO defined daily dose (DDD)
900 mg
Not a recommended dose. The DDD is the assumed average maintenance dose per day for a drug used for its main indication in adults. It is a statistical measure used for research and comparison purposes only.
Source: WHO Collaborating Centre for Drug Statistics Methodology, distributed via the NHS dm+d supplementary BNF/ATC mapping files (NHSBSA). Contains public sector information licensed under the Open Government Licence v3.0.
Therapeutically similar medicines
Similarity is based on WHO Anatomical Therapeutic Chemical (ATC) classification and on a factual NHS dm+d therapeutic-grouping code prefix. Source data: NHS dm+d via TRUD (OGL v3.0), WHO ATC/DDD Index.
Guidelines from the National Institute for Health and Care Excellence
NICE clinical guidance(1)
Source: National Institute for Health and Care Excellence (NICE). Contains public sector information licensed under the Open Government Licence v3.0.
Check stock at pharmacies and supply information
Pharmacy stock checkers
Search for this medicine at major UK pharmacy chains. These links open the retailer's own website — results depend on their current online catalogue.
Supply & safety information
Official UK regulator monitoring and safety alerts
Pharmacy links redirect to the retailer's own search and do not represent real-time stock levels. Shortage and safety information sourced from MHRA drug safety updates (gov.uk, Crown Copyright under OGL v3.0).
Codes for healthcare professionals and prescribing systems
These codes are used by healthcare IT systems and prescribers to identify this medicine.
NHS UK identifiers
Browse tools
SNOMED CT and dm+d codes from NHS TRUD (Technology Reference data Update Distribution), licensed under the Open Government Licence v3.0. BNF code shown is the factual mapping value distributed by NHS Business Services Authority (NHSBSA) in the dm+d supplementary file under OGL v3.0; it is not affiliated with, nor licensed from, the publishers of the British National Formulary. ATC codes from the WHO Collaborating Centre for Drug Statistics Methodology (whocc.no).
Active and completed clinical studies from ClinicalTrials.gov
Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine (NLM), National Institutes of Health (NIH). Data accessed via ClinicalTrials.gov API v2. Trial information is provided for research purposes and does not constitute medical advice.
Academic studies and reviews for this medicine's active substance
Showing the 50 most relevant studies.
Reviews & meta-analyses: 3 · 1982–2026
Showing the 50 most relevant studies, sorted by most relevant.
H. Albrecht, P. Dicpinigaitis, E. Guenin
Multidisciplinary Respiratory Medicine, 2017
Jill Ohar, James F. Donohue, Selwyn Spangenthal
Chronic Obstructive Pulmonary Diseases Journal of the COPD Foundation, 2019
M. Bateman, Stephen Brunton, Wendy L Wright, et al.
Postgraduate Medicine, 2025
- Common Cold
- Cough
- Guaifenesin
Michael M. Crowley, Anke Fredersdorf, Britta Schroeder, et al.
European Journal of Pharmaceutical Sciences, 2004
- Drug Interactions
- Guaifenesin
- Ketoprofen
Osman Duman, Sibel Tunç, Bahar Kancı Bozoğlan
Journal of Fluorescence, 2013
- Circular Dichroism
- Binding Sites
- Energy Transfer
SA Greene, J. C. Thurmon, William J. Tranquilli, et al.
American Journal of Veterinary Research, 1986
- Anesthesia, General
- Blood Pressure
- Cardiovascular System
Tahani Y. A. Alanazi, Samar M. Mahgoub, Hoda A. Ahmed, et al.
Reviews in Analytical Chemistry, 2025
A. Roshdy, R. A. Salam, Ghada M. Hadad, et al.
Luminescence : the journal of biological and chemical luminescence, 2024
- Guaifenesin
- Codeine
- Morpholines
A. A. Zaitsev, I. Leshchenko, N. A. Esaulova, et al.
Terapevticheskii arkhiv, 2023
- Bronchitis
- Bromhexine
- Ambroxol
AIM To evaluate the efficacy and safety of a combination drug containing ambroxol, guaifenesin, and levosalbutamol, oral solution, versus Ascoril Expectorant, syrup (combination of bromhexine, guaifenesin, and salbutamol) in the treatment of productive cough in adult patients with acute bronchitis. MATERIALS AND METHODS This open-label, randomized, phase III study included patients with acute bronchitis who had a productive cough with difficulty in sputum expectoration. 244 patients were randomized in a 1:1 ratio and received 10 mL of the study drug or reference drug 3 times daily for 2 weeks. After 7 and 14 days of treatment, the physician evaluated patient's subjective complaints and the efficacy of therapy. The primary endpoint was the proportion of patients with high and very high efficacy. RESULTS The primary endpoint was reached by 70 (0.5738) patients in the study drug group and 54 (0.4426) in the reference drug group (p=0.04). The intergroup difference was 0.1311 [95% confidence interval: 0.0057; 0.2566]. The lower limit of the 95% confidence interval was above zero, which confirms the superiority of therapy with the study drug over therapy with Ascoril Expectorant. The proportion of patients with a 1-point total score reduction and with complete resolution of all symptoms according to the Modified Cough Relief and Sputum Expectoration Questionnaire after 7 and 14 days was numerically higher in the study drug group versus the reference drug group. There were no statistically significant differences between the groups in the incidence of adverse events. CONCLUSION The efficacy of a new combination drug containing ambroxol, guaifenesin, and levosalbutamol in the treatment of productive cough in adult patients with acute bronchitis is superior to the efficacy of Ascoril Expectorant. The safety profiles of the study drug and the reference drug were comparable.
Abstract licence: CC BY-NC-SA 4.0
Muthana S. Ali, Ali E. Karim, Maiser Z. Mohye, et al.
Al-Kitab Journal for Pure Sciences, 2023
Sources: aggregated from Europe PMC (EMBL-EBI), OpenAlex, Crossref, PubMed and other open scholarly databases. Retracted articles are excluded. Study information is provided for research purposes and does not constitute medical advice.
Pharmacology and chemical data from DrugBank
Key facts
Drug status
Approved
Major interactions
None known
Half-life
Not available
Mechanism
Although the exact mechanism of action of guaifenesin may not yet be formally or…
Food interactions
2 warnings
Human targets
1 target
Data: DrugBank · CC BY-NC 4.0
Pharmacokinetics at a glance
Absorption
Half-life
Protein binding
Volume of distribution
116L
Metabolism
400 mg
Elimination
Clearance
94.8 L/h
Pharmacokinetic data: DrugBank · CC BY-NC 4.0
Regardless, on March 1, 2007, the FDA received a petition asking the FDA to notify the public that some antitussives, expectorants, decongestants, antihistamines, and cough/cold combinations are not known to be safe and effective in children under the age of 6 years F4525. After the negotiation between FDA and major manufacturers, a voluntary transition of labels for not using guaifenesin in children under the age of 4 years was endorsed by FDA in 2008 F4525.
Furthermore, there has also been contemporary research to suggest that guaifenesin possesses and is capable of demonstrating anticonvulsant and muscle relaxant effects to some degree possibly by acting as an NMDA receptor antagonist [A177652].
[L6100]
Although adequate and well-controlled studies in pregnant women have not been performed, the Collaborative Perinatal Project monitored 197 mother-child pairs exposed to guaifenesin during the first trimester .
[L6100]
An increased occurrence of inguinal hernias was found in the neonates .
[L6100]
However, congenital defects were not strongly associated with guaifenesin use during pregnancy in 2 large groups of mother-child pairs .
[L6100]
Moreover, guaifenesin is excreted in breast milk in small quantities .
[L6100]
Subsequently, caution should be exercised by balancing the potential benefit of treatment against any possible risks .
[L6100]
Additionally, an LD50 value of 1510 mg/kg (rat, oral) has been reported for guaifenesin MSDS.
Consequently, while it is generally proposed that guaifenesin functions as an expectorant by helping to loosen phlegm (mucus) and thin bronchial secretions to rid the bronchial passageways of bothersome mucus and make coughs more productive, there has also been research to suggest that guaifenesin possesses and is capable of demonstrating anticonvulsant and muscle relaxant effects to some degree possibly by acting as an NMDA receptor antagonist [A177652].
How the body processes this drug — absorption, distribution, metabolism, and elimination
[A177676][L6100]
Moreover, it has been observed that guaifenesin also experiences both oxidation and demethylation .
[A177676]
In particular, the medication is quickly metabolized hepatically by way of oxidation to β-(2-methoxyphenoxy)-lactic acid .
[A177676]
Furthermore, guaifenesin is also demethylated by O-demethylase in liver microsomes to the point where about 40% of an administered dose is excreted as this metabolite in the urine within 3 hours .
[A177676]
In fact, O-demethylase appears to be the primary enzyme for the metabolism of guaifenesin and the primary metabolites of the substance are β-(2-methoxyphenoxy)-lactic acid and the demethylated hydroxyguaifenesin, both of which are themselves inactive moieties .
[A177676]
Proteins and enzymes this drug interacts with in the body
GluN3B subunit also binds D-serine and, in the absence of glycine, activates glycinergic receptor complexes, but with lower efficacy than glycine (By similarity). Each GluN3 subunit confers differential attributes to channel properties, including activation, deactivation and desensitization kinetics, pH sensitivity, Ca2(+) permeability, and binding to allosteric modulators (By similarity)
ATC R05CA03
Chemical identifiers
CAS, UNII, InChI Key and database cross-references
Show
Chemical identifiers
CAS, UNII, InChI Key and database cross-references
Linked compound data from DrugBank Open Data (CC BY-NC 4.0)
Guaifenesin
Additional database identifiers
Drugs Product Database (DPD)
9615
ChemSpider
3396
BindingDB
50240098
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4584
GenAtlas
GRIN1
GeneCards
GRIN1
GenBank Gene Database
D13515
GenBank Protein Database
219920
Guide to Pharmacology
455
UniProt Accession
NMDZ1_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4585
GenAtlas
GRIN2A
GeneCards
GRIN2A
GenBank Gene Database
U09002
GenBank Protein Database
558749
Guide to Pharmacology
456
UniProt Accession
NMDE1_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4586
GenAtlas
GRIN2B
GeneCards
GRIN2B
GenBank Gene Database
U90278
GenBank Protein Database
1899202
Guide to Pharmacology
457
UniProt Accession
NMDE2_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4587
GenAtlas
GRIN2C
GeneCards
GRIN2C
GenBank Gene Database
L76224
GenBank Protein Database
1196449
Guide to Pharmacology
458
UniProt Accession
NMDE3_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:4588
GenAtlas
GRIN2D
GeneCards
GRIN2D
GenBank Gene Database
U77783
GenBank Protein Database
2444026
UniProt Accession
NMDE4_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:16767
GenAtlas
GRIN3A
GeneCards
GRIN3A
GenBank Gene Database
AJ416950
GenBank Protein Database
20372905
UniProt Accession
NMD3A_HUMAN
HUGO Gene Nomenclature Committee (HGNC)
HGNC:16768
GenAtlas
GRIN3B
GeneCards
GRIN3B
GenBank Gene Database
AC004528
GenBank Protein Database
3025446
UniProt Accession
NMD3B_HUMAN
DrugBank citations
If you use DrugBank data in your research, please cite the following publications:
Show earlier publications
Structured knowledge from the free knowledge base
ATC classifications (Wikidata)
Linked open data from Wikidata (Q420682), a free and open knowledge base operated by the Wikimedia Foundation. Data is available under the Creative Commons CC0 1.0 Public Domain Dedication. WHO INN from the World Health Organization.