DRUG | SUPPLIED | DOSE | COMMENTS |
---|---|---|---|
VALPROIC ACID (Paeds) (Depakene, (also see divalproex)) Mechanism of action: Anticonvulsant Ref: 44, 83, 336, 337, 338, 556, 557 Last update: 2022-09-13 |
capsule: 250 mg enteric coated capsule: 500 mg syrup: 50 mg/mL IV: 100 mg/mL (Available through Health Canada Special Access Programme only) |
TID dosing may be required for some patients for tolerability or achieving target serum levels. Seizures: Children: Initial: 2.5-5 mg/kg/dose PO/IV BID Increase by: 2.5-5 mg/kg/dose PO/IV BID every 5-7 days Maintenance: 10-15 mg/kg/dose PO/IV BID PR: 10-15 mg/kg/dose Q8HMaximum: 20-30 mg/kg/dose PO/IV BID or 1500 mg/dose PO/IV BID, whichever is less (Use higher maximum of 60 mg/kg/24 hr only in rare cases, based on individual clinical response) Adolescents: Initial: 125-250 mg/dose PO/IV BIDIncrease by: 125-250 mg/dose PO/IV BID every 5-7 days Maintenance: 500-1000 mg/dose PO/IV BID Maximum: 1500 mg/dose PO/IV BID Refractory status epilepticus: 30-40 mg/kg/dose IV (Max: 3000 mg/dose) (Consider lower dose if patient already on maintenance therapy) |
Hazardous drug. Refer to Hazardous Drug Handling Policy in PHSA SHOP Avoid in mitochondrial/urea cycle disorders. Caution in < 2 yrs old: increased risk of hepatic failure, particularly in those with undiagnosed inborn errors of metabolism. Teratogenic: Risk of significant congenital malformations if taken during pregnancy Effective as a mood stabilizer in bipolar disorder and for migraine prophylaxis - see divalproex. Do not chew or crush enteric coated capsule. Can give PR as a retention enema (use valproic acid syrup diluted 1:1 with water). IV administration rate up to 1.5-3 mg/kg/min see IV manual. Dose related adverse effects: GI upset, drowsiness, tremor, weight gain, thrombocytopenia, hair loss. Idiosyncratic adverse effects: hepatotoxicity , pancreatitis, hyperammonemia. Associated with Polycystic Ovarian Syndrome in reproductive age females. Monitor CBC and liver function at baseline and periodically. Substrate of CYP 2C9, 2C19; inhibits CYP 2C9, 2C19; highly protein bound. Check for drug Interactions. Post load (valproic acid) level to be taken 1 hour after IV load or 3 hours after PO load. Target Level: 350-700 micromoles/L. See Therapeutic Drug Monitoring in References and Supplementary (white pages in hard copy). Standard Prescription: valproic acid__mg PO/IV Q__H (__mg/kg/24hr) |