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Solution for injection containing promethazine hydrochloride.

Drugs List

  • PHENERGAN 25mg/1ml injection
  • promethazine hydrochloride 25mg/1ml injection
  • promethazine hydrochloride 50mg/2ml injection
  • Therapeutic Indications


    Allergic reaction - responsive to antihistamines
    Paediatric sedative - short term use
    Premedication - sedative
    Shock - anaphylactic

    Unlicensed Uses

    Sedation of children and adolescents on Intensive Care Units


    Intravenous injection should be performed with extreme care to avoid extravasation or inadvertent intra-arterial injection, which could lead to necrosis and peripheral gangrene. If a patient complains of pain during intravenous injection, stop the injection immediately, as this may be a sign of extravasation or inadvertent intra-arterial injection. Intramuscular injection must also be performed carefully to avoid inadvertent subcutaneous injection, which could lead to local necrosis.


    25mg to 50mg (1ml to 2ml) by deep intramuscular injection.
    In emergency, the injection solution containing 2.5% solution may be diluted to 10 times its volume with water for injections immediately before use and given by slow intravenous injection.
    Maximum parenteral dose 100mg.


    Children aged 10 to 18 years
    25mg to 50mg (1ml to 2ml) by deep intramuscular injection.
    In emergency, the injection solution containing 2.5% solution may be diluted to 10 times its volume with water for injections immediately before use and given by slow intravenous injection.
    Maximum parenteral dose 100mg.

    Children aged 5 to 10 years
    6.25mg to 12.5mg (0.25ml to 0.5ml) by deep intramuscular injection.

    The following alternative dosing schedule may be suitable for sedation of children in intensive care:
    Children aged 10 to 12 years:
    500micrograms/kg to 1mg/kg up to four times a day. Maximum single dose is 25mg.

    Children aged 1 month to 10 years (unlicensed):
    500micrograms/kg to 1mg/kg up to four times a day. Maximum single dose is 25mg.


    For deep intramuscular injection.

    It may be given by slow intravenous injection after dilution to 10 times its volume with water for injections at a rate not exceeding 25mg per minute. The maximum parenteral dose is 100mg.


    Incompatible with alkaline substances, which precipitate the insoluble promethazine base.


    Neonates under 1 month
    Within 2 weeks of discontinuing MAOIs
    2 weeks prior to estimated delivery date
    Central nervous system depression
    Long QT syndrome
    Torsade de pointes

    Precautions and Warnings

    Children under 2 years
    Family history of long QT syndrome
    Bladder outflow obstruction
    Diabetes mellitus
    Electrolyte imbalance
    Epileptic disorder
    Hepatic disorder
    History of torsade de pointes
    Narrow angle glaucoma
    Pyloroduodenal obstruction
    Renal impairment
    Reye's syndrome or Reye-like symptoms in children or adolescents
    Severe ischaemic heart disease

    Adjustment of hypoglycaemic therapy may be necessary in diabetes mellitus
    Correct electrolyte disorders before treatment
    May mask ototoxicity caused by ototoxic drugs e.g. salicylates
    Patients with diabetes may experience fluctuations in blood glucose
    Suppressed vomiting may mask diagnosis of raised ICP or GI obstruction
    Advise impaired alertness may affect ability to drive or operate machinery
    Contains sulfite. Discontinue if hypersensitivity reactions occur
    For deep intramuscular injection
    For slow intravenous injection only after diluting correctly
    Breastfeeding: Monitor infant for systemic effects of treating the mother
    Consider monitoring ECG in patients at risk of QT prolongation
    Monitor carbohydrate metabolism in diabetes mellitus
    Monitor serum electrolytes
    Discontinue 72 hours before skin tests involving allergies
    Immunological pregnancy tests may produce false results during treatment
    Advise patient to avoid alcohol during treatment
    Pregnancy: Not recommended in the 2 weeks prior to estimated delivery date
    Advise patient to avoid exposure to direct sunlight

    Use with caution in patients with asthma, bronchitis or bronchiectasis as promethazine may thicken or dry lung secretions and impair expectoration.

    Pregnancy and Lactation


    Promethazine is contraindicated in the 2 weeks prior to the delivery date.

    Promethazine has been in widespread use for many years and it seems unlikely that its use during pregnancy is associated with major birth defects. The majority of surveillance studies have found no association with promethazine use and malformations. Only one such study found a possible association with any major defects (cardiac) but other factors (mother's disease, concurrent drug use etc) may have been involved with this observation.

    Significant neonatal respiratory depression was observed in a small group of patients following promethazine use during labour. However no respiratory depression was seen in three other large studies. Transient behavioural and EEG changes were seen in newborns in another study. The use of promethazine is not recommended by some manufacturers in the 2 weeks prior to delivery in view of the risk of irritability and excitement in the neonate.

    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 promethazine with caution in breastfeeding.

    Available evidence suggests that the amount of promethazine excreted in breast milk is insignificant. However, there are risks of neonatal irritability and excitement and that the infant should be monitored for excess sedation if the mother is on repeated doses.

    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 disorders
    Blood dyscrasias
    Blurred vision
    Circulatory collapse
    CNS depression
    Dry mouth
    Excitement (paradoxical)
    Extrapyramidal effects
    Gastric irritation
    Gastro-intestinal symptoms
    Glaucoma (closed angle)
    Haemolytic anaemia
    Hepatic impairment
    Hypersensitivity reactions
    Muscle spasm
    Pain on intramuscular injection
    Psychomotor impairment
    Sleep disturbances
    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: October 2016

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 2nd edition (2007) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    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: Phenergan Injection. Sanofi. Revised August 2016.

    Summary of Product Characteristics: Promethazine Hydrochloride Injections. Goldshield plc. Revised September 2007.

    NICE Evidence Services Available at: Last accessed: 13 September 2017

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Promethazine Last revised: 10 March 2015
    Last accessed: 06 April 2016

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