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Guaifenesin with diphenhydramine hydrochloride and levomenthol oral


Oral formulation containing guaifenesin, diphenhydramine hydrochloride and levomenthol

Drugs List

  • Therapeutic Indications


    Cough with viscous sputum
    Night time relief of cough



    10ml (two 5ml spoonfuls) at bedtime followed by 10ml (two 5ml spoonfuls) every 6 hours.

    Or 10ml (two 5ml spoonfuls) four times a day.

    Do not take more than 40ml (eight 5ml spoonfuls) in 24 hours.


    Children 12 years and over
    10ml (two 5ml spoonfuls) at bedtime followed by 10ml (two 5ml spoonfuls) every 6 hours.

    Or 10ml (two 5ml spoonfuls) four times a day.

    Do not take more than 40ml (eight 5ml spoonfuls) in 24 hours.


    Children under 12 years
    Within 2 weeks of discontinuing MAOIs
    Hereditary fructose intolerance

    Precautions and Warnings

    Benign prostatic hyperplasia
    Chronic cough
    Excessive bronchial secretions
    Glucose-galactose malabsorption syndrome
    Hepatic impairment
    Narrow angle glaucoma
    Renal impairment
    Urinary retention

    Advise patient drowsiness may affect ability to drive or operate machinery
    Contains glucose
    Preparation contains sucrose
    May affect results of some laboratory tests
    Advise patient to avoid alcohol during treatment
    Advise patient not to exceed stated dose
    Advise patient to consult a doctor if symptoms persist despite treatment

    MHRA/CHM advice (February 2009)

    Cough and cold remedies containing guaifenesin, diphenhydramine hydrochloride 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

    Guaifenesin is considered to be possibly porphyrinogenic and therefore, it should be used only when no safer alternative is available.

    Martindale says diphenhydramine has been associated with acute attacks. NAPOS website has not yet classified the drug and advises, therefore, it is not used. However 'European Porphyria Iniciative' and 'Welsh Medicines Information Porphyria' classifies the drug as safe.

    Pregnancy and Lactation


    Guaifenesin with diphenhydramine and levomenthol should be used with caution in pregnancy.

    Animal data and most published human experience suggest that diphenhydramine does not cause complications in pregnancy. There is one report of a statistical association with cleft palate following first trimester exposure. Premature infants exposed within two weeks of birth may be at risk of toxicity.

    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 to 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 on the internet ( ) or if this is unavailable at the backup site ( ).


    Guaifenesin with diphenhydramine and levomenthol should be used with caution in breastfeeding.

    Diphenhydramine should not be used during lactation as small amounts of antihistamines are excreted in breast milk. Data is limited in humans but expected breast milk concentrations are not thought to be sufficiently high to affect a nursing infant.

    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

    Side Effects

    Blurred vision
    Difficulty in micturition
    Dry mouth
    Dry throat
    Dryness of nose
    Gastro-intestinal symptoms
    Hypersensitivity reactions


    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 ( ).

    Further Information

    Last Full Review Date: May 2016

    Reference Sources

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 9th edition (2011) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.
    Summary of Product Characteristics: Benylin Mucus Cough Night. Revised January 2012.

    Dear Healthcare Professional Letter. Medicines and Healthcare products Regulatory Agency. 28th February 2009.
    Last accessed: 26 May 2016.

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Diphenhydramine; Last revised: 7 September 2013
    Last accessed: 26 May 2016

    The Welsh Medicines Information Centre (WMIC) - Porphyria Information Service.
    Available at:
    Last accessed: 26 May 2016

    The Norwegian Porphyria Centre (NAPOS).
    Available at:
    Last accessed: 26 May 2016

    European Porphyria Network (EpNet).
    Available at:
    Last accessed: 26 May 2016

    The Drug Database for Acute Porphyria (NAPOS)
    Available at:
    Last accessed: 13 July 2015
    Last revised: 23 April 2010

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