Sodium valproate poisoning

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    Poisoning - acute guidelines for initial management

    Key points

    1. Toxicity is dose-dependent and serious symptoms are unlikely with ingestions less than 400 mg/kg
    2. Sodium valproate concentrations and an ECG can be helpful in assessment
    3. Early consideration of transfer to a tertiary centre due to need for intensive care support (eg enhanced elimination with haemodialysis)

    For 24 hour advice, contact the Poisons Information Centre 13 11 26


    Symptom onset is usually within 4 hours for standard release preparations, and up to 12 hours following enteric-coated formulations

    Monitoring of drug concentrations can be helpful, particularly in the case of larger ingestions. Bone marrow suppression may occur 3 to 5 days after massive ingestion

    Children requiring assessment

    • All children with deliberate self-poisoning or significant accidental ingestion (>200 mg/kg in drug naïve children OR 50 mg/kg more than the child’s usual single therapeutic dose)
    • Any symptomatic child
    • Acute ingestion of unknown quantity
    • Any child where the developmental age is inconsistent with accidental poisoning as non-accidental poisoning should be considered

    Risk assessment


    • Intentional overdose or accidental
    • Dose:
      • Stated or likely dose taken
      • Presented as syrup, immediate or enteric coated tablets
      • If possible, determine the exact name and tablet size
      • Calculate the maximum possible dose per kg
    • Consider the possibility of co-ingestants (eg paracetamol), either accidental or deliberate  
    Sodium valproate dose response relationship:
    • <200 mg/kg — unlikely to develop more than mild sedation
    • 200 to 400 mg/kg — moderate toxicity with CNS depression
    • >400 mg/kg — risk of multi-organ system toxicities
    • >1000 mg/kg — coma, multi-organ failure, cerebral oedema, potentially life-threatening


    • Central nervous system: drowsiness, ataxia, seizures, coma
    • Gastrointestinal: nausea, vomiting, abdominal pain
    • Cardiovascular: hypotension, arrhythmias (QT prolongation), tachycardia
    • Metabolic: hypernatraemia, elevated lactate, metabolic acidosis, hypocalcaemia, hypoglycaemia, hyperammonaemia, deranged liver function tests
    • Myelosuppression – late onset

    Always check for Medicalert bracelet in any unconscious patient, or any other signs of underlying medical condition (fingerprick marks etc.)


    • ECG: initially and repeat at 6 hours until normal
    • Sodium valproate serum concentration:
      • Measure every 6 hours in patients with altered conscious state until the concentration returns to normal
      • Therapeutic range (total valproic acid concentration): 350 to 700 micromol/L (50 to 100 mg/L or micrograms/mL)
      • >6000 micromol/L (850 mg/L) is associated with severe poisoning
    • Blood glucose concentration
    • Electrolytes, liver function test, blood gas, ammonia, calcium
    • Paracetamol concentration in all intentional overdoses

    Acute Management

    All cases of ingestions >400 mg/kg should be discussed with a toxicologist early in regard to decontamination

    1. Resuscitation

    • Supportive treatment to maintain adequate blood pressure and electrolyte balance is essential
    • IV fluid resuscitation 20 mL/kg for hypovolaemia or hypotension
    • Potassium and glucose administration as necessary

    2. Decontamination

    • This should be in discussion with a toxicologist (see discharge information section below for contact details)
    • Consider charcoal if large ingestion (>200 mg/kg ingested) and presentation within 4 hours of ingestion, after discussion with toxicology. Ensure patient is not drowsy or has secure airway (ie intubated)
    • Consider multi-dose activated charcoal for ingestions >500 mg/kg or rising sodium valproate levels
    • Enhanced elimination (eg haemodialysis) is considered in life-threatening poisoning – ingestions >1 g/kg or drug concentrations >6000 micromol/L

    3. Antidote: Carnitine

    • The use of carnitine as an antidote for sodium valproate is not supported by strong evidence, but there is a reasonable biological bases for its use. It is inexpensive and has a low risk of harm
    • Consider using carnitine in patients with sodium valproate poisoning complicated by:
      • significant metabolic acidosis
      • cerebral oedema
      • hyperammonaemia
      • hepatotoxicity
    • If indicated start with 100 mg/kg IV followed by 50 mg/kg every 8 hours until coma or acidosis resolve

    Ongoing care and monitoring

    Mild symptoms
    (eg ataxia, gastrointestinal symptoms)

    • Observe for 6 hours if ingestion of immediate-release preparation or minimum of 12 hours if ingestion of enteric coated preparation
    • Discharge if symptom-free

    Moderate-to-severe or persistent symptoms after 6 hours of observation OR ingestions >400 mg/kg
    (eg depressed conscious state or cardiac arrhythmias)

    • Admit for observation and supportive management in a tertiary centre
    • Serum sodium valproate concentration should be performed at 6 hours
    • If ongoing symptoms, serial drug concentration monitoring should be discussed with a toxicologist (see contact details below)

    Consider consultation with local paediatric team when

    • Any child or young person presents with intentional overdose as admission should be considered
    • Children have persisting symptoms after 6 hours observation

    Consult the Poisons Information Centre 13 11 26 for advice

    Consider transfer when

    • A child has ingested >1 g/kg sodium valproate or valproate serum concentrations >6000 micromol/L
      • the child should be transferred to an intensive care unit with dialysis facilities
    • A child has severe symptoms with the potential to require intensive care review or care required is beyond the comfort level of the current hospital 

    For emergency advice and paediatric or neonatal ICU transfers, see Retrieval Services

    Consider discharge when

    • Normal GCS
    • Normal ECG
    • Period of observation as above

    Assessing risk and connecting to community services

    • Prior to discharge, adolescents who present with deliberate ingestions need a risk assessment regarding the likelihood of further ingestions or other attempts to self-harm
    • Assessment of other drug and alcohol use should also be undertaken
    • If, after risk assessment, it is deemed safe to discharge a patient from hospital, but ongoing mental health or drug and alcohol needs are identified, the adolescent should be linked with appropriate services 

     Discharge information and follow-up

    Parent Information: Poisoning prevention for children   

    Poisons Information Centre: phone 13 11 26


    Mental Health, Drug and Alcohol Services

    New South Wales

    Child and Adolescent Mental Health Services: services delivered across NSW Health with referrals made via the NSW Mental Health Line (1800 011 511) for 24-hour advice, assessment referral information.

    Youth Health and Wellbeing: includes links to Assessment Guideline for providers caring for young people aged 12 – 24 years across settings, as well as links to other resources 

    Your room: information on alcohol and other drug use, including fact sheets (multiple languages), assessment tools and links to support services.


    Child and Youth Mental Health Services: specialise in helping infants, children and young people up to age 18 years with complex mental health needs.

    Dovetail: provides clinical advice and professional support to workers, services and communities who engage with young people affected by alcohol and other drug use

    Queensland Youth AOD Services Guide: created by Dovetail, this guide provides an overview of youth alcohol and other drug treatment services across Queensland. For help outside of hours, call the 24-hour Alcohol and Drug Information Service (ADIS) on 1800 177 833.

    Clarence St, Mater Young Adult Health Service: Youth drug and alcohol service


    Child & Adolescent Mental Health Services (CAMHS): Victorian government mental health services are region-based

    YSAS (Youth Support and Advocacy Service): Outreach teams across Melbourne and regional Victoria for young people experiencing significant problems with alcohol and/or drug use

    YoDAA: Victoria’s Youth Drug and Alcohol Advice service - provides information and support for youth AOD needs or anyone concerned about a young person

    Infoxchange Service Seeker: Search for local community support services eg local doctor, dentist, counselling services, drug and alcohol services

    Last updated December 2020

  • Reference List

    1. IBM Micromedex 2019, Sodium valproate, viewed November 2019, <>
    2. National Poisons Centre New Zealand 2019, Sodium Valproate, TOXINZ™ Poisons Information, viewed November 2019, <>
    3. eTG Therapeutic Guidelines. Toxicology –Sodium Valproate Poisoning. (viewed November 2020)