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Injection of lorazepam.

Drugs List

  • lorazepam 4mg/1ml injection
  • Therapeutic Indications


    Acute excitement
    Acute mania
    Anxiety state
    Premedication - sedative
    Status epilepticus

    Preoperative medication or premedication for uncomfortable or prolonged investigations.

    For the treatment of acute anxiety states, acute excitement or acute mania.

    For the control of status epilepticus.


    Dosage and duration of therapy should be individualised. The lowest effective dose should be prescribed for the shortest time possible.


    0.05mg/kg (3.5mg for an average 70kg man). The injection should be given 30 to 45 minutes before surgery, by intravenous route, when sedation will be evident after 5 to 10 minutes and the maximal loss of recall will happen after 30 to 45 minutes. By intramuscular route, the injection should be administered 1 to 1.5 hours before surgery when sedation will be evident after 30 to 45 minutes and maximal loss of recall will happen after 60 to 90 minutes.

    Acute Anxiety
    0.025mg/kg to 0.03mg/kg (1.75mg to 2.1mg for an average 70kg man). Repeat every 6 hours.

    Status Epilepticus
    4mg intravenously.


    Initial dose: reduce the initial dose by approximately 50% and adjust the dosage as needed and tolerated.


    Children aged 12 to 18 years
    (See Dosage; Adult)

    The following dosage may also be suitable, however not licensed for use in children under 12 years:
    Children aged 1 month to 18 years
    50micrograms/kg to 100micrograms/kg by intravenous injection 30 to 45 minutes before surgery. Maximum of 4mg per dose.

    Acute Anxiety
    Children aged 12 to 18 years
    (See Dosage; Adult)

    Not recommended for use in children under 12 years.

    Status Epilepticus
    2mg intravenously.

    The following dosing schedule may also be suitable:

    Children aged 12 to 18 years
    4mg intravenously as a single dose repeated once after 10 minutes if necessary into a large vein.

    Children aged 1 month to 12 years
    100micrograms/kg as a single dose by slow intravenous injection. If considered necessary dose may be repeated once after 10 minutes into a large vein. Maximum of 4mg per dose.


    100micrograms/kg as a single dose, repeated once after 10 minutes if necessary into a large vein.

    Additional Dosage Information

    Debilitated patients
    Initial dose: reduce the initial dose by approximately 50% and adjust the dosage as needed and tolerated.


    Injection can be administered intravenous (preferred route) in larger veins or intramuscularly.

    Precautions should be considered to avoid injection into small veins and intra-arterial route.

    Intravenous injection should be administered slowly except in the control of status epilepticus where rapid injection is required.


    Hypersensitivity to benzyl alcohol
    Acute respiratory impairment
    Myasthenia gravis
    Severe hepatic impairment
    Sleep apnoea

    Precautions and Warnings

    Females of childbearing potential
    Severe illness
    Acute narrow angle glaucoma
    Chronic obstructive pulmonary disease
    Chronic respiratory impairment
    History of alcohol abuse
    History of drug misuse
    History of seizures
    Mild hepatic impairment
    Personality disorder
    Reduced respiratory reserve
    Renal impairment

    Advise patient ability to drive or operate machinery may be impaired
    Advise patient not to drive or operate machinery within 24-48 hours of dose
    Advise patient not to drive until they know how the medicine affects them
    Advise patient this medicine is subject to driving restrictions
    Not recommended for chronic administration
    Not suitable as sole treatment of depression or anxiety with depression
    Contains benzyl alcohol
    Injection contains propylene glycol
    A patent airway and adequate oxygenation must be maintained
    Ventilatory support facilities must be immediately available
    For intravenous or intramuscular administration only
    May cause respiratory depression
    Monitor haematological parameters regularly throughout treatment
    Observe patient for at least 8 hours post injection
    Potential for drug abuse
    Prolonged or excessive use may result in dependence
    Amnesia may occur
    May cause anaphylactic / anaphylactoid reactions
    Potential for withdrawal symptoms
    Withdrawal symptoms may follow short courses at normal doses
    Avoid abrupt withdrawal
    Advise patient to seek advice at first indications of pregnancy
    Discontinue if angioedema occurs
    Discontinue if paradoxical reactions occur
    Consider dose reduction in hepatic impairment
    Consider dose reduction in renal impairment
    Not licensed for all indications in all age groups
    Reduce dose in elderly
    Advise patient not to take alcohol during and for 48 hours after therapy
    Advise that effects are potentiated by CNS depressants (including alcohol)
    Advise patient on possible rebound phenomena on withdrawal

    Although hypotension has been observed only rarely, benzodiazepines should be administered with caution to patients, like the elderly, in whom a drop in blood pressure might lead to cardiovascular or cerebrovascular complications.

    Patients receiving lorazepam as an outpatient should be accompanied when discharged.

    Care should be exercised to patients with status epilepticus, especially when the patient has received other central nervous system depressants.

    Angioedema has been reported during treatment, some may experience additional symptoms such as dyspnoea, throat closing or nausea and vomiting. If angioedema involves the tongue, glottis or larynx, airway obstruction may be fatal.

    Withdrawal symptoms can appear after as little as one week of therapy. Withdrawal symptoms may occur when treatment is changed from long duration of action to short duration of action.

    Treatment may have a disinhibiting effect and can cause suicidal tendencies in depressed patients.

    Consider a more specific treatment if anxiety or insomnia present.

    Allergic reactions may be caused by benzyl alcohol, only if necessary should high volumes be used, particularly those at risk of accumulation and toxicity.

    Medical monitoring is required in paediatric patients with liver or hepatic function impairment receiving more than or equal to 50mg/kg/day of propylene glycol because of renal failure, renal dysfunction and liver dysfunction.

    Pregnancy and Lactation


    Lorazepam is contraindicated during pregnancy.

    The manufacturer does not recommend the use of lorazepam during pregnancy, especially during the first and last trimesters unless administration is deemed clinically justifiable by a physician. Since there is not enough data regarding obstetrical safety of parenteral lorazepam (including use in caesarean section), its use is also not recommended.

    Treatment may cause foetal damage when administered to pregnant women. The use of lorazepam during the late phase of pregnancy may require ventilation for the infant at birth. Using lorazepam during the late phase of pregnancy or during labour at high doses can lead to effects on the neonate such as hypothermia, hypotonia and moderate respiratory depression. Infants of mothers who ingested benzodiazepines for several weeks or more preceding delivery presented withdrawal symptoms during the postnatal period. Other symptoms presented in neonates born of mothers taking benzodiazepines during the late phase of pregnancy or at delivery are apnoea, feeding problems and impaired metabolic response to cold stress.

    Briggs (2015) suggests that lorazepam crosses the placenta. High doses used near delivery may lead to the "floppy infant" syndrome.


    Use lorazepam with caution during breastfeeding.

    The manufacturer does not recommend breastfeeding whilst taking lorazepam unless the expected benefit to the women outweighs the potential harm to the infant. Available data suggests lorazepam is present in breast milk.

    LactMed (2021) indicates that lorazepam is found in low levels in breastmilk and can be safely administered directly to infants. Evidence suggests that lorazepam does not cause any adverse effects in breastfed infants with usual maternal dosages. No special precautions are required.

    Briggs (2015) indicates that in prolonged exposures the effects of lorazepam can be of concern, according to the American Academy of Paediatrics.

    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). This medicine may be subject to police testing and has specified maximum blood levels for driving.
    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.
    It is an offence to drive while under the influence of this medicine. However, a patient is not committing an offence (called 'statutory defence') if: 1. The medicine has been prescribed to treat a medical or dental problem and 2. The medicine has been taken according to the instructions given by the prescriber and/or in the information provided with the medicine, and 3. The medicine was not affecting the ability to drive safely. For further guidance see

    Side Effects

    Allergic skin reactions
    Blood dyscrasias
    Blurred vision
    Cardiac arrest
    Changes in libido
    Concentration disturbances
    Decrease in blood pressure
    Exacerbation of obstructive pulmonary disease
    Extrapyramidal effects
    Gastro-intestinal disturbances
    Hypersensitivity reactions
    Inappropriate secretion of antidiuretic hormone
    Increase in alkaline phosphatase
    Increases in hepatic enzymes
    Local pain (injection site)
    Muscle weakness
    Orgasmic dysfunction
    Paradoxical reactions
    Pre-existing depression may be unmasked
    Respiratory depression
    Serum bilirubin increased
    Sexual disturbances
    Skin reactions
    Sleep disturbances
    Slurred speech
    Suicidal tendencies
    Throat tightness
    Visual disturbances
    Withdrawal symptoms

    Withdrawal Symptoms and Signs

    Withdrawal symptoms may appear following the cessation of treatment and can occur after as little as one week of therapy. Patients should be informed that treatment will be of limited duration and that discontinuation of treatment will be gradual.

    Symptoms of withdrawal include, headaches, muscle pain, anxiety, tension, depression, insomnia, restlessness, confusion, irritability, sweating, and a rebound phenomena. In severe cases derealisation, depersonalisation, hyperacusis, tinnitus, numbness and tingling of the extremities, hypersensitivity to light, noise and physical contact, involuntary movements, vomiting, hallucinations and convulsions may occur.

    Patients should be aware of the 'rebound' phenomena to reduce anxiety should symptoms occur.


    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: September 2021

    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.

    Summary of Product Characteristics: Lorazepam Macure 4mg/ml solution for injection. Macure Pharma UK Ltd. Revised March 2021. 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: 10 September 2021

    NICE Evidence Services Available at: Last accessed: 10 September 2021

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Available at:
    Lorazepam Last revised: 21 June 2021
    Last accessed: 07 October 2021

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