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Guaifenesin with menthol


Oral liquid containing 100mg guaifenesin and 1.1mg levomenthol in each 5ml.

Drugs List

  • guaifenesin 100mg/5ml and levomenthol 1.1mg/5ml oral solution
  • Therapeutic Indications


    Symptomatic relief of chesty cough.



    10ml four times a day.


    Children 12 years and over
    10ml four times a day.


    For oral use.


    Children under 12 years.

    Porphyria (See under 'Porphyria sec.')

    Hereditary fructose intolerance.

    Precautions and Warnings

    Use with caution in the following:
    Severe renal impairment.
    Severe hepatic impairment.

    Preparation contains sucrose and liquid glucose and caution should, therefore, be exercised in patients with glucose-galactose malabsorption syndrome.

    Preparation contains alcohol.

    Persistent / chronic cough such as occurs with asthma, or cough accompanied by excessive secretion: use guaifenesin with menthol only on physician's advice.

    Pregnancy (see Pregnancy section).
    Lactation (see Lactation section).

    Advise patient to consult a doctor if symptoms persist despite treatment.

    If urine is collected within 24hours of a dose of guaifenesin a metabolite of guaifenesin may cause a colour interference with laboratory determinations of urinary 5-hydroxyindoleacetic acid (5-HIAA) and vanillylmandelic acid (VMA).

    CSM Warnings

    MHRA/CHM advice (February 2009)

    Cough and cold remedies containing guaifenesin and levomenthol should no longer be used in children under 6 as the balance of benefits and risk has not been shown to be favourable.

    However, the MHRA/CHM also lists a number of combination products which are being phased out from the market for use in children under 12 years. This product is included on this list, therefore, it is not recommended for children up to the age of 12 years.

    MHRA/CHM advice (March 2008)

    Children should not be given more than one cough or cold preparation at a time because different brands may contain the same active ingredient; care should be taken to give the correct dose.

    Use in Porphyria

    Martindale considers guaifenesin to be unsafe in patients with porphyria because it has been shown to be porphyrinogenic in animals. NAPOS website says it should be used only when no safer alternative is available.

    Pregnancy and Lactation


    There is insufficient information available to determine if guaifenesin has teratogenic or mutagenic potential. There is no data to support an association between guaifenesin and congenital defects.

    Animal studies show that menthol does not produce statistically significant teratogenic effects in rats, rabbits and mice, and has no mutagenic potential.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14-17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password at ( ) or if this is unavailable at the backup site ( ).


    At the time of writing, there is no published experience concerning the use of guaifenesin during breast feeding.

    Guaifenesin is excreted in breast milk in small amounts with no effects expected on the infant.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Effects on Ability to Drive and Operate Machinery

    No effects likely.


    Advise patient to consult a doctor if symptoms persist despite treatment.

    Side Effects

    Gastrointestinal discomfort

    Effects on Laboratory Tests

    If urine is collected within 24hours of a dose of guaifenesin a metabolite of guaifenesin may cause a colour interference with laboratory determinations of urinary 5-hydroxyindoleacetic acid (5-HIAA) and vanillylmandelic acid (VMA).


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Shelf Life and Storage

    Store below 30 degrees C.

    Reference Sources

    Summary of Product Characteristics: Benylin Mucus Cough, McNeil Products Ltd, revised May 2009.

    Martindale: The Complete Drug Reference, 35th edition (2007) ed. Sweetman, S. Pharmaceutical Press, London. British National Formulary, 57th Edition (2009) Pharmaceutical Press, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 8th edition (2008) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Dear Healthcare Professional Letter. Medicines and Healthcare products Regulatory Agency. 28th February 2009.
    Last accessed: 14th September, 2009.

    Last accessed: 14th September, 2009

    NICE Evidence Services Available at: Last accessed:17 August 2017

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