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Pethidine hydrochloride

Updated 2 Feb 2023 | Opioid analgesics


Solution for injection containing pethidine hydrochloride 100mg in10ml
Solution for injection containing pethidine hydrochloride 50mg in 5ml

Solution for injection containing pethidine hydrochloride 100mg in 2ml
Solution for injection containing pethidine hydrochloride 50mg in1ml

Drugs List

  • pethidine 100mg/10ml injection
  • pethidine 100mg/2ml injection
  • pethidine 50mg/1ml injection
  • pethidine 50mg/5ml injection
  • Therapeutic Indications


    Pre-anaesthetic medication

    Analgesia during anaesthesia

    Obstetric analgesia

    Management of moderate to severe pain

    Not all brands are licensed for all indications


    Treatment should be supervised by a specialist.


    Management of moderate to severe pain (including post-operative pain)
    By intramuscular or subcutaneous injection: 25mg to 100mg
    By slow intravenous injection: 25mg to 50mg.
    Dose not usually repeated more often than 4 hourly. Some sources suggest that intramuscular or subcutaneous injections can be repeated every 2 to 3 hours if necessary.

    Obstetric analgesia
    By intramuscular or subcutaneous injection: 50mg to 100mg. Repeat after 1 to 3 hours as required
    Maximum dose in 24 hours: 400mg.

    Pre-anaesthetic medication
    By intramuscular injection: 25mg to 100mg, given 60 minutes before operation.

    Enhancement of analgesia
    By slow intravenous injection: 10mg to 25mg as required.


    Use with caution. Elderly patients are more likely to be susceptible to the central depressant effects of pethidine.

    The initial dose should not exceed 25mg. The total daily dose may need to be reduced in elderly patients receiving repeated doses.


    Pre-anaesthetic medication
    By intramuscular injection: 1mg/kg to 2mg/kg, given 60 minutes before operation.

    Management of moderate to severe pain (including post-operative pain)
    By intramuscular injection: 0.5mg/kg to 2mg/kg every 4 hours.

    Obstetric analgesia (unlicensed)
    Children aged 12 to 18 years
    By subcutaneous or intramuscular injection: 1mg/kg (up to 100mg per dose). Repeat 1 to 3 hours later if necessary.
    Maximum dose in 24 hours: 400mg.

    Patients with Renal Impairment

    Severe renal impairment
    Not recommended.

    Mild to moderate renal impairment
    A dose reduction may be required.

    There may be increased cerebral sensitivity if used in patients with renal impairment. Accumulation of potentially toxic metabolites may result, particularly with repeat dosing.

    Patients with Hepatic Impairment

    Severe hepatic impairment
    Not recommended.

    Mild to moderate hepatic impairment
    A dose reduction may be required.

    If used in patients with hepatic impairment, pethidine may precipitate coma, and clearance may be prolonged.


    Solution for injection for intramuscular, intravenous or subcutaneous administration.


    Solution for injection

    For single use only. Any unused portion should be discarded.

    The injection should be administered immediately after the ampoule is opened.


    For slow intravenous administration, the solution for injection may be diluted to 10ml with Water for Injections.

    Following dilution, chemical and physical in-use stability has been demonstrated for 24 hours at 25 degrees C.
    If not used immediately, the in-use storage times and conditions prior to use are the responsibility of the user. These would not normally be for longer than 24 hours at 2 - 8 degrees C, unless dilution occurred under controlled and validated aseptic conditions.


    Pethidine solution for injection is incompatible with the following:
    Heparin sodium
    Hydrocortisone sodium succinate
    Methicillin sodium
    Methyl prednisolone succinate
    Morphine sulfate
    Phenytoin sodium
    Sodium bicarbonate
    Sodium iodide
    Sulfadiazine sodium
    Thiamylal sodium
    Aciclovir sodium
    Potassium iodide
    Liposomal doxorubicin hydrochloride



    Acute respiratory depression

    Obstructive airways disease

    Acute asthma

    Respiratory insufficiency

    Within 2 weeks of discontinuing MAOI's

    Acute alcoholism

    Increased intracranial pressure

    Convulsive disorders

    Paralytic ileus
    Risk of paralytic ileus

    Head injury

    Severe renal impairment

    Severe hepatic impairment


    Delirium tremens

    Supraventricular tachycardia

    Diabetic acidosis

    Within 7 days of discontinuing safinamide

    Precautions and Warnings

    Treatment should be supervised by a specialist.

    Use with caution and reduce dose if necessary in patients with the following conditions:
    Mild to moderate renal impairment - see Dosage; Renal Impairment
    Mild to moderate hepatic impairment - see Dosage; Hepatic Impairment
    Biliary tract disorders
    Hypothyroidism - reduce dose
    Adreno-cortical insufficiency - reduce dose
    Prostatic hypertrophy
    Inflammatory bowel disorders
    Obstructive bowel disorders
    Myasthenia gravis
    Cardiac arrhythmias
    Severe cor pulmonale
    Reduced respiratory reserve
    History of convulsive disorders
    Elderly - see Dosage; Elderly
    Children - see Dosage; Children
    Neonates and premature infants

    Pethidine neurotoxicity may occur in patients with renal failure, cancer or sickle cell anaemia if concurrent anticholinergics are administered or during prolonged administration of increasing pethidine doses.

    Use with caution in debilitated patients. A reduction in dosage may be advisable in these patients.

    Use with caution in patients with drug addiction or a history of drug addiction.

    Pregnancy - see Pregnancy section

    Breastfeeding - see Lactation section

    Repeated use can lead to tolerance and dependence. Withdrawal symptoms may occur on cessation of therapy, therefore abrupt withdrawal should be avoided.

    Pethidine may cause drowsiness. The ability to drive or operate machinery may be severely affected during and for some time after the administration of pethidine. If affected patients should be advised not to drive or operate machinery.

    Not all available brands are licensed for all indications.

    Pregnancy and Lactation


    The manufacturer advises that pethidine may only be administered during pregnancy if the expected benefits outweigh the potential risks.

    Safety of pethidine administration during pregnancy has not been adequately established. However, this product has been widely used for many years without apparent ill consequence, and epidemiologic studies have not uncovered an association between use during the first trimester and congenital malformations. Animal studies have not shown any hazard associated with pethidine.

    Pethidine crosses the placenta rapidly during pregnancy. It can reach higher foetal concentrations than in maternal serum due to the limited metabolic capacity of the foetus: pethidine is decomposed slowly and has a considerably lengthened half-life of 18 hours, compared to 3-4 hours in adults.

    Administration during labour may cause respiratory depression in the neonate and gastric stasis and inhalation pneumonia in the mother. However, Schaefer states that pethidine is the analgesic of choice during labour as labour is not lengthened, the strength of contractions is not diminished, and neither the severity of bleeding or the involution of the uterus is influenced. Neonates may experience withdrawal symptoms if the mother is dependent on pethidine.

    Schaefer concludes that although use as an analgesic during pregnancy is not recommended, inadvertent use does not require either a termination or additional diagnostic procedures.

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


    The manufacturer advises that pethidine may only be administered during breastfeeding if the expected benefits outweigh the potential risks.

    Pethidine is excreted in breast milk. No adverse effects in nursing infants were reported in studies of mothers who had received pethidine during labour. However, the long half-life of pethidine and its metabolite may result in neonatal plasma accumulation, especially in premature infants. Schafer recommends that pethidine is acceptable if necessary, but because of its depressive effect on respiration, particular care should be taken with children with a tendency towards apnoea. A physician should be contacted immediately if the neonate shows signs of increased sleepiness, difficulty breastfeeding, breathing difficulties or limpness.

    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

    This class of medicine is in the list of drugs included in regulations under 5a of the Road Traffic Act 1988 (England and Wales). When prescribing this medicine: Advise patient the medicine can affect cognitive function and is likely to affect ability to drive. Advise patient not to drive until they know how the medicine affects them.


    Advise patients that their ability to drive and operate machinery may be impaired by treatment.

    Side Effects

    Respiratory depression
    Anaphylactic reaction
    Orthostatic hypotension
    Facial flushing
    Loss of mental acuity
    Mood changes
    Blurred vision
    Double vision
    Visual disturbances
    Dry mouth
    Biliary spasm
    Injection site reactions
    Urinary retention
    Difficulty in micturition
    Ureteric spasm
    Anti-diuretic effect
    CNS excitation
    Reduced libido
    Reduction of male potency
    Decreased corneal reflex
    Dry eye
    Muscle twitch
    Renal colic
    Sexual dysfunction
    Muscle rigidity
    Sleep disturbances


    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

    Do not store above 25 degrees C
    Keep in the outer carton

    Further Information

    Last Full Review Date: July 2011

    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, 8th edition (2008) ed. Briggs, G., Freeman, R. and Yaffe, S. Lippincott Williams & Wilkins, Philadelphia.

    Medications and Mothers' Milk, 14th Edition (2010) Hale, T. Hale Publishing, Amarillo, Texas.

    Summary of Product Characteristics: Pethidine Injection 50mg/ml. Auden McKenzie Ltd. Revised July 2010
    Summary of Product Characteristics: Pethidine Injection 1%. Martindale Pharmaceuticals. Revised July 2008
    Summary of Product Characteristics: Pethidine Injection 5%. Martindale Pharmaceuticals. Revised October 2009
    Summary of Product Characteristics: Pethidine Injection. Goldshield. Revised April, 2008 Government departments. Department for Transport. Publications. Drug driving and medicine: advice for healthcare professionals. Drug driving: Guidance for healthcare professionals on drug driving. Available at: Last accessed: 6 January 2015
    New drug driving offence implications for medicines packaging. Medicines Regulatory News. 10 December 2013. Available at: Last accessed: 6 January 2015

    NICE Evidence Services Available at: Last accessed: 14 September 2017

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Meperidine - Record 365. Last revised: July 5, 2011
    Last accessed: July 19, 2011

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