See also
Poisoning - acute guidelines for initial management
Resuscitation
Key points
- Toxicity is dose-dependent and serious symptoms are unlikely with ingestions less than 400 mg/kg
- Sodium valproate concentrations and an ECG can be helpful in assessment
- 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
Background
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
History
- 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
Examination
- 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.)
Investigations
- 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
Websites:
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.
Queensland
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
Victoria
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