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Chlorphenamine oral

Updated 2 Feb 2023 | Sedating antihistamines


Oral formulations containing chlorphenamine maleate.

Drugs List

  • ALLERIEF 2mg/5ml oral solution
  • ALLERIEF 4mg tablets
  • chlorphenamine 2mg/5ml oral solution
  • chlorphenamine 2mg/5ml oral solution sugar-free
  • chlorphenamine 4mg tablets
  • HAYLEVE 4mg tablets
  • PIRITON 2mg/5ml syrup
  • PIRITON 4mg tablets
  • PIRITON ALLERGY 4mg tablets
  • Therapeutic Indications


    Allergic reaction - responsive to antihistamines
    For the symptomatic relief of itch associated with chickenpox



    4mg (10ml) every 4 to 6 hours. Maximum daily dose 24mg (60ml).


    A lower daily dose should be considered to a maximum of 12mg (30ml) in 24 hours as these patients are more likely to suffer from confusional psychosis and other neurological anticholinergic effects.


    Not all formulations are licensed in children under 6 years.

    Children aged 12 to 18 years
    4mg (10ml) every 4 to 6 hours. Maximum daily dose 24mg (60ml).

    Children aged 6 to 12 years
    2mg (5ml) every 4 to 6 hours. Maximum daily dose 12mg (30ml) in any 24 hours.

    Children aged 2 to 6 years
    1mg (2.5ml) every 4 to 6 hours. Maximum daily dose 6mg (15ml) in any 24 hours.

    Children aged 1 to 2 years
    1mg (2.5ml) twice daily. The minimum interval between doses should be 4 hours. Maximum daily dose 2mg (5ml).

    Children aged 1 month to 1 year (unlicensed)
    1mg (2.5ml) twice daily.


    Neonates under 1 month
    Within 2 weeks of discontinuing MAOIs

    Precautions and Warnings

    Children under 18 years
    Benign prostatic hyperplasia
    Cardiovascular disorder
    Epileptic disorder
    Glucose-galactose malabsorption syndrome
    Hepatic impairment
    Hereditary fructose intolerance
    Lactose intolerance
    Pyloroduodenal obstruction
    Raised intra-ocular pressure
    Renal impairment
    Severe hypertension
    Urinary retention

    Advise ability to drive/operate machinery may be affected by side effects
    Not all available brands are licensed for use in children under 6 years
    Not all formulations are licensed for all uses
    Oral solution with maltitol unsuitable in hereditary fructose intolerance
    Some formulations contain lactose
    Some formulations contain sucrose
    Reduce dose in elderly
    Should not be taken with other cough or cold medicine
    Advise patient to avoid alcohol during treatment
    Alcohol may enhance side effects

    Pregnancy and Lactation


    Use chlorphenamine with caution in pregnancy.

    The manufacturers note that the safety of chlorphenamine in pregnancy has not been established. Use during the third trimester may result in reactions in the newborn or premature neonates.

    Briggs notes the use of chlorphenamine in pregnancy as having a low risk of harm to the foetus but an association between exposure during the last 2 weeks of pregnancy to antihistamines in general and retrolental fibroplasia in premature infants has been reported.

    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 ( ).


    Use chlorphenamine with caution in breastfeeding.

    The manufacturers note that small amounts of antihistamines may be excreted in breast milk and may inhibit lactation.

    Medications and Mothers' Milk note that although no data is available on chlorphenamine and its excretion into breast milk, it has not been reported to produce side effects. Sedation is the only likely side effect.

    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

    Abdominal pain
    Anaphylactic reaction
    Antimuscarinic effects
    Blood dyscrasias
    Blurred vision
    Chest tightness
    Dry mouth
    Excitement (paradoxical)
    Exfoliative dermatitis
    Extrapyramidal effects
    Gastro-intestinal disturbances
    Haemolytic anaemia
    Hair loss
    Hepatic impairment
    Hypersensitivity reactions
    Impaired concentration
    Muscle weakness
    Sleep disturbances
    Thickening of bronchial secretions
    Urinary retention


    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 2018

    Reference Sources

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.

    Medications and Mothers' Milk, Sixteenth Edition (2014) Hale, T and Rowe, H, Hale Publishing, Plano, Texas.

    Summary of Product Characteristics: Allerief 2mg/5ml oral solution. Crescent Pharma Limited. Revised March 2018.

    Summary of Product Characteristics: Allerief 4mg tablets. Crescent Pharma Limited. Revised December 2017.

    Summary of Product Characteristics: Hayleve. Chelonia Healthcare Limited. Revised August 2016.

    Summary of Product Characteristics: Piriton Allergy Tablets. GlaxoSmithKline Consumer Healthcare (UK) Trading Limited. Revised April 2016.

    Summary of Product Characteristics: Piriton Tablets. GlaxoSmithKline Consumer Healthcare (UK) Trading Limited. Revised April 2016.

    Summary of Product Characteristics: Piriton Syrup. GlaxoSmithKline Consumer Healthcare (UK) Trading Limited. Revised March 2016.

    NICE Evidence Services Available at: Last accessed: 08 May 2018

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