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Chlorphenamine parenteral

Updated 2 Feb 2023 | Sedating antihistamines


Solution for injection containing chlorphenamine maleate

Drugs List

  • chlorphenamine 10mg/1ml injection
  • Therapeutic Indications


    Allergic reaction - responsive to antihistamines
    Anaphylaxis acute - emergency treatment

    Allergic reactions including acute urticaria, control of allergic reactions to insect bites and stings, angioneurotic oedema, drug and serum reactions, desensitisation reactions, hayfever, vasomotor rhinitis, severe pruritus of non-specific origin.



    Anaphylactic reaction
    10mg to 20mg repeated if required up to a maximum of 40mg in 24 hours.
    If rapid effect is needed, the intravenous route is recommended alongside emergency therapy with adrenaline (epinephrine), corticosteroids, oxygen and supportive therapy as needed. In this instance chlorphenamine injection is injected slowly over a period of one minute, using the smallest adequate syringe. Any drowsiness, giddiness or hypotension which may follow is usually transitory.

    Blood transfusion reaction
    10mg to 20mg by subcutaneous route. This can be repeated up to a total of 40mg within a 24 hour period, or oral forms of chlorphenamine may be given until the symptoms subside.

    Prevention of delayed reaction
    Chlorphenamine injection may be helpful in preventing delayed reactions to penicillin and other drugs when given separately by intramuscular injection immediately prior to administration of the other drug. 10mg is the usual dose. Chlorphenamine injection is not to be depended upon to prevent anaphylactic reactions in patients who have known allergies to particular drugs.


    Dose is calculated on child's age or child's body weight:

    Children aged 12 to 18 years
    10mg to 20mg (or 200 micrograms/kg).

    Children aged 6 to 12 years
    5mg to 10mg (or 200 micrograms/kg).

    Children aged 1 to 6 years
    2.5mg to 5mg (or 200 micrograms/kg).

    Children aged 1 month to 1 year
    250 micrograms/kg.

    Extra care should be taken when preparing injection for children under 1 year due to small volumes required. Dilution of chlorphenamine should assist the preparation.

    The following alternative dosing schedule may be suitable:

    Children aged 12 to 18 years
    10mg, repeated if required up to 4 times in 24 hours.

    Children aged 6 to 12 years
    5mg, repeated if required up to 4 times in 24 hours.

    Children aged 6 months to 6 years
    2.5mg, repeated if required up to 4 times in 24 hours.

    Children aged under 6 months
    250 micrograms/kg (maximum 2.5 mg), repeated if required up to 4 times in 24 hours.


    By subcutaneous, intramuscular or by intravenous injection over 1 minute.


    Neonates under 1 month
    Within 2 weeks of discontinuing MAOIs

    Precautions and Warnings

    Children 1 month to 18 years
    Benign prostatic hyperplasia
    Cardiovascular disorder
    Epileptic disorder
    Hepatic impairment
    Pyloroduodenal obstruction
    Raised intra-ocular pressure
    Severe hypertension
    Urinary retention

    Advise ability to drive/operate machinery may be affected by side effects
    Advise patient to avoid alcohol during treatment
    Alcohol may enhance side effects

    Pregnancy and Lactation


    Use chlorphenamine with caution in pregnancy.

    The manufacturer notes 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, Freeman & Yaffe note that an association between exposure during the last 2 weeks of pregnancy to antihistamines in general and retrolental fibroplasia in premature infants has been reported. They categorise the use of chlorphenamine in pregnancy as having a very low risk of harm to the foetus.

    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 manufacturer notes that it is reasonable to assume that chlorphenamine may inhibit lactation and may be excreted in breast milk.

    However, 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

    Antimuscarinic effects
    Blood dyscrasias
    Blurred vision
    CNS stimulation
    Dry mouth
    Exfoliative dermatitis
    Extrapyramidal effects
    Gastro-intestinal disturbances
    Haemolytic anaemia
    Hepatic impairment
    Hyperexcitability (children)
    Hypersensitivity reactions
    Impaired concentration
    Injection site reactions
    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: March 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.

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

    Summary of Product Characteristics: Chlorphenamine Injection. Kyowa Kirin Ltd. Revised March 2017.

    Summary of Product Characteristics: Chlorphenamine Injection. Wockhardt UK Ltd. Revised January 2016.

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

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