Pregnancy Risk Category D
How supplied
valproate sodium
Syrup: 250 mg/5 ml
valproic acid
Tablets (enteric-coated): 200 mg‡, 500 mg‡
Tablets (crushable): 100 mg‡
Capsules: 250 mg
Syrup: 200 mg/5 ml‡
divalproex sodium
Capsules (delayed-release): 125 mg
Tablets (enteric-coated): 125 mg, 250 mg, 500 mg
Injection: 500-mg vial
Action
Unknown. Probably increases brain levels of gamma-aminobutyric acid, which transmits inhibitory nerve impulses in the CNS.
Indications & dosage
Simple and complex absence seizures, mixed seizure types (including absence seizures)--
Adults and children: initially, 15 mg/kg P.O. or I.V. daily; then increase by 5 to 10 mg/kg daily at weekly intervals up to maximum of 60 mg/kg daily.
Mania (divalproex sodium only)--
Adults and children: initially, 750 mg daily in divided doses. Adjust dosage based on patient's response; maximum dose is 60 mg/kg/day.
Prophylaxis for migraine headache (divalproex sodium only)--
Adults: initially, 250 mg P.O. b.i.d. Some patients may require up to 1,000 mg/day.
Complex partial seizures--
Adults and children ages 10 and older: 10 to 15 mg/kg P.O. or I.V. daily; then increase by 5 to 10 mg/kg daily at weekly intervals, up to 60 mg/kg/day.
Elderly: reduce initial dose.
Adverse reactions
CNS: asthenia, sedation, emotional upset, depression, psychosis, aggressiveness, hyperactivity, behavioral deterioration, muscle weakness, tremor, ataxia, headache, dizziness, incoordination.
EENT: nystagmus, diplopia.
GI: nausea, vomiting, indigestion, diarrhea, abdominal cramps, constipation, increased appetite, anorexia, pancreatitis.
Hematologic: thrombocytopenia, increased bleeding time, petechiae, bruising, eosinophilia, hemorrhage, leukopenia, bone marrow suppression.
Hepatic: elevated liver enzyme levels, toxic hepatitis.
Metabolic: weight gain.
Skin: rash, alopecia, pruritus, photosensitivity, erythema multiforme.
Interactions
Drug-drug. Aspirin, chlorpromazine, cimetidine, erythromycin, felbamate: may cause valproic acid toxicity. Use together cautiously and monitor blood levels. Monitor patient closely.
Benzodiazepines, other CNS depressants: excessive CNS depression. Avoid concomitant use.
Lamotrigine: increased lamotrigine levels, decreased valproate levels. Monitor levels closely.
Phenobarbital: increased phenobarbital levels. Monitor patient closely.
Phenytoin: increased or decreased phenytoin levels, decreased valproate levels. Monitor patient closely.
Rifampin: may decrease valproate levels. Monitor levels.
Warfarin: valproic acid may displace warfarin from binding sites. Monitor PT and INR.
Drug-lifestyle: Alcohol use: excessive CNS depression. Avoid concomitant use.
Effects on diagnostic tests
Drug may produce false-positive results for urine ketones.
Contraindications
Contraindicated in patients with hypersensitivity to drug and in those with hepatic disease or significant hepatic dysfunction.
Nursing considerations
I.V. administration
Patient teaching
*Liquid contains alcohol. **May contain tartrazine. †Canada ‡Australia §U.K. OTCOver the counter
Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE-THREATENING