Sodium Valproate

Question 1

Monitor

Answer 1

Liver function, full blood count, weight, BMI.

Question 2

Warning signs

Answer 2

• Persistent vomiting, abdominal pain, anorexia
• Jaundice, oedema, malaise drowsiness
• Loss of seizure control
• Suicidal ideation or behaviour

Question 3

Actions Required

Answer 3

• All women of child bearing age must be enrolled in a pregnancy prevention programme.
Prescribers should ensure the patient understands the risks associated with valproate use in
pregnancy, the need to use effective contraception, the need for regular review of treatment
and that the woman should rapidly consult her doctor if she is planning a pregnancy or
becomes pregnant.
• Treatment in women of child bearing age should not have therapy initiated without a negative
pregnancy test. They should also have regular pregnancy tests throughout therapy.
• Women of child bearing potential should use an effective method of contraception throughout
treatment. A user independent contraceptive method such as an IUD or implant is preferred
or two complementary forms of contraception including a barrier method should be used.
• Patients that are immobilised for long periods or have inadequate sun exposure or dietary
intake of calcium should take vitamin supplementation.
• Category 2 antiepileptic, brand dispensing based on clinical judgement.
• Abrupt withdrawal should be avoided, the valproate dose should be reduced gradually over at
least 4 weeks.

Question 4

Interactions

Answer 4

• Effects of other psychotropics such as antipsychotics, MAO inhibitors, antidepressants and
benzodiazepines potentiated.
• Anticoagulant effect of warfarin increased.
• Metabolism of lamotrigine reduced and its half-life almost doubled, leading to increased
lamotrigine toxicity particularly serious skin reactions.
• Erythromycin and cimetidine may increase valproic acid plasma levels by reducing hepatic
metabolism.
• Anti-epileptics with enzyme inducing effect decrease valproic acid plasma concentrations.