Symptoms and signs
The effects of acute toxicity from guaifenesin may include gastro-intestinal discomfort, nausea and drowsiness.
When taken in excess, guaifenesin may cause renal calculi.
Treatment
Treatment should be symptomatic and supportive.
This product is contraindicated in individuals with known hypersensitivity to the product, or any of its components.
Not to be used in children under the age of 12 years.
None known
The safety of guaifenesin/menthol is based on available data from clinical trials and adverse drug reactions (ADRs) identified during post-marketing experience are included.
The frequencies are provided according to the following convention:
Very common >1/10
Common >1/100 and < 1/10
Uncommon >1/1,000 and <1/100
Rare >1/10,000 and <1/1,000
Very rare <1/10,000, including isolated reports
Not known (cannot be estimated from the available data)
ADRs are presented for frequency category based on 1) incidence in adequately designed clinical trials or epidemiology studies if available or 2) when incidence cannot be estimated, frequency category is listed as 'Not known'
Adverse Drug Reactions identified During Clinical trials, Epidemiology studies and Post-Marketing Experience with Guaifenesin. Frequency Category Estimated from Clinical Trials or Epidemiology Studies.
| Body system | Incidence | Reported adverse event |
| Immune System Disorders | Not known | Hypersensitivity reactions (hypersensitivity, pruritus and urticaria) Rash |
| Gastrointestinal Disorders | Not known | Abdominal pain upper Diarrhoea Nausea Vomiting |
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard
Carcinogenicity
There is insufficient information available to determine whether guaifenesin or menthol have carcinogenic potential.
Mutagenicity
There is insufficient information available to determine whether guaifenesin has mutagenic potential.
The results of a range of tests suggest that menthol does not have a mutagenic potential.
Teratogenicity
There is insufficient information available to determine whether guaifenesin has teratogenic potential.
The results of a number of studies suggest that the administration of menthol does not produce any statistically significant teratogenic effects in rats, rabbits and mice.
Fertility
There is insufficient information available to determine whether guaifenesin or menthol have the potential to impair fertility.
Benylin Extra Strength Mucus & Phlegm (Non-drowsy) is indicated for the symptomatic relief of cough.
Pharmacotherapeutic Group: Cough and cold preparations, Expectorants. ATC Code: R05CA10
Guaifenesin is thought to exert its pharmacological action by stimulating receptors in the gastric mucosa. This increases the output from secretory glands of the gastrointestinal system and in reflex increases the flow of fluids from glands lining the respiratory tract. The result is an increase in volume and decrease in viscosity of bronchial secretions. Other actions may include stimulating vagal nerve endings in bronchial secretory glands and stimulating certain centres in the brain which in turn enhance respiratory fluid flow. Guaifenesin produces its expectorant action within 24 hours.
Menthol has mild local anaesthetic, decongestant and antitussive properties.
Absorption
Guaifenesin is well absorbed from the gastro-intestinal tract following oral administration, although limited information is available on its pharmacokinetics. After the administration of 600 mg guaifenesin to healthy adult volunteers, the Cmax was approximately 1.4 ug/ml, with tmax occurring approximately 15 minutes after drug administration.
Menthol is well absorbed from the gastrointestinal tract following oral administration.
Distribution
No information is available on the distribution of guaifenesin or menthol in humans.
Metabolism and elimination
Guaifenesin appears to undergo both oxidation and demethylation. Following an oral dose of 600 mg guaifenesin to 3 healthy male volunteers, the t½ was approximately 1 hour and the drug was not detectable in the blood after approximately 8 hours.
Menthol is hydroxylated in the liver by microsomal enzymes to p-methane -3,8 diol. This is then conjugated with glucuronide and excreted both in urine and bile as the glucuronide.
Pharmacokinetics in Renal/Hepatic Impairment
There have been no specific studies of this product, menthol or guaifenesin in hepatic or renal impairment.
Pharmacokinetics in the Elderly
There have been no specific studies in the use of this product, menthol or guaifenesin in the elderly.
This product should not be used for persistent or chronic cough, such as occurs with asthma, or where cough is accompanied by excessive secretions, unless directed by a physician.
Caution should be exercised when using the product in the presence of severe renal or severe hepatic impairment, [See Pharmacokinetics].
Patients with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency should not take this medicine.
This medicinal product contains 5 vol % ethanol (alcohol), i.e. up to 200 mg per 5ml dose, equivalent to approximately 5 ml beer, 2 ml wine per 5 ml dose. This can be harmful for those suffering from alcoholism. The ethanol content should be taken into account in pregnant or breast-feeding women, children and high-risk groups such as patients with liver disease or epilepsy.
This product contains 16.42mg of sodium per 5ml. This should be taken into consideration by those on a controlled sodium diet.
This product contains Ponceau 4R (E124) red colouring which may cause allergic reactions.
This product has no or negligible influence on the ability to drive or operate machinery.
Adults and children aged 12 years and over:
Oral. Two 5 ml spoonfuls four times a day.
Children under 12 years:
This product is contraindicated in children under the age of 12 years.
The Elderly:
As for adults.
Hepatic/renal dysfunction
Experience with the use of this product suggests that normal adult dosage is appropriate for mild to moderate dysfunction. Caution should be exercised in severe hepatic and severe renal impairment. [See Pharmacokinetics].
Do not exceed the stated dose.
Keep out of the reach and sight of children.
No special requirements.
Any unused product or waste material should be disposed of in accordance with local requirements.
Administrative data
