Valproate
A broad-spectrum antiepileptic also used for bipolar disorder and migraine prevention; a major teratogen avoided in pregnancy.
Also called valproic acid (acid form), sodium valproate (sodium salt, the usual UK form) or divalproex sodium (US name; also called valproate semisodium).
Drug card
- How it works
- Raising brain GABA and blocking sodium channels for broad seizure control
- Used for
- Focal and generalized epilepsy
- Absence seizures
- Bipolar disorder
- Preventing migraine
- Known for
- Liver failure, mostly in the first 6 months
- Birth defects such as spina bifida, and lower IQ
- Pancreatitis
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does valproate work?
Valproic acid and its salts all act as the valproate ion. Its mechanism is not established: it raises brain GABA, probably by inhibiting GABA transaminase and other GABA-degrading enzymes, and may also inhibit voltage-sensitive sodium channels. It inhibits glucuronidation, so lamotrigine levels rise when the two are combined.
Uses
What is valproate used for?
- Focal and generalized epilepsy
- Absence seizures
- Bipolar disorder
- Preventing migraine
Side effects
Side effects of valproate
- Liver failure, mostly in the first 6 monthsKnown forSerious
- Birth defects such as spina bifida, and lower IQKnown forSerious
- PancreatitisKnown forSerious
- Weight gain
- Tremor
- Hair thinning
- Nausea, vomiting and stomach pain
- Drowsiness
- Low platelets and bleedingSerious
- High ammonia, with drowsiness or confusionSerious
- Irregular periods and reduced fertility
- Suicidal thoughtsSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Avoid in anyone who could become pregnant unless no other treatment works; then use highly effective contraception and a pregnancy prevention programme.
- In the womb it causes malformations in about 11% of babies and neurodevelopmental disorders in up to 30 to 40%.
- Liver failure risk is highest in the first 6 months, in children under 2 and in POLG mitochondrial disease; check liver tests.
- It more than doubles lamotrigine levels; carbapenems can drop valproate levels and let seizures return.
Good to know: In the UK, girls and women under 55 can start valproate only if two specialists independently agree that no other treatment is effective or tolerated.
Remember it
A way to remember it
VALPROATE
- V
- Very teratogenic: spina bifida and lower IQ
- A
- Alopecia (hair thinning)
- L
- Liver failure
- P
- Pancreatitis
- R
- Raised ammonia
- O
- Overweight: weight gain
- A
- Absence seizures are among its uses
- T
- Tremor
- E
- Enzyme inhibition: raises lamotrigine levels
Written for biofideX
Its class
Valproate
How valproate works is not fully established. It raises GABA levels in the brain, probably by inhibiting GABA transaminase and other enzymes that break GABA down, and it may also inhibit voltage-sensitive sodium channels to curb repetitive firing. This broad action lets it control focal, generalized tonic-clonic and absence seizures. It also inhibits glucuronidation, raising lamotrigine levels.
Easily mixed up with sodium channel-blocking antiepileptics, succinimides and lithium.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Valproic acid oral solution: label (DailyMed)
- Sodium Valproate 500mg Gastro-Resistant Tablets: SmPC (emc)
- Valproic Acid (NCI Thesaurus)
- Divalproex Sodium (NCI Thesaurus)
- Sodium valproate (NHS)
- Lamotrigine orally disintegrating tablets: label (DailyMed)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Epilepsy and nerve pain
Valproate is one of 8 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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