Valproic Acid (Depakote / Depakene)
valproic acid · divalproex sodium · sodium valproate
Indications
| Indication | Approved Population | Therapy Type | Status |
|---|---|---|---|
| Manic episodes of bipolar disorder | Adults | Monotherapy or adjunctive (acute mania) | FDA Approved |
| Complex partial seizures | ≥10 years | Monotherapy or adjunctive | FDA Approved |
| Simple and complex absence seizures | All ages (monotherapy/adjunctive) | Monotherapy or adjunctive | FDA Approved |
| Multiple seizure types including absence | All ages | Adjunctive | FDA Approved |
| Migraine prophylaxis | Adults | Prophylaxis only (NOT acute treatment) | FDA Approved |
Valproic acid is among the broadest-spectrum antiepileptic drugs available, effective against both focal and generalised seizure types including absence seizures. It is also a cornerstone treatment for acute bipolar mania and serves as a prophylactic agent for migraine headaches. However, its use in women of childbearing potential is significantly restricted by its established teratogenicity, and it carries three FDA boxed warnings that shape all prescribing decisions.
Status epilepticus (IV formulation) — Used as a second-line agent after benzodiazepine failure. IV loading at 20–40 mg/kg. Evidence quality: Moderate (supported by AES guidelines and comparative data).
Agitation in acute psychiatric settings — IV valproate loading for rapid control of agitation. Evidence quality: Low–Moderate (case series and small trials).
Dosing
Adult Dosing by Clinical Scenario
| Clinical Scenario | Starting Dose | Maintenance Dose | Maximum Dose | Notes |
|---|---|---|---|---|
| Acute bipolar mania | 750 mg/day in divided doses (DR) | Titrate to clinical response; target trough 50–125 mcg/mL | 60 mg/kg/day | Increase rapidly to therapeutic levels; response typically within 14 days ER formulation: start 25 mg/kg/day once daily |
| Complex partial seizures — monotherapy initiation | 10–15 mg/kg/day | Titrate by 5–10 mg/kg/week; target trough 50–100 mcg/mL | 60 mg/kg/day | Optimal response usually below 60 mg/kg/day Give in divided doses if total daily dose exceeds 250 mg |
| Complex partial seizures — adjunctive therapy | 10–15 mg/kg/day | Titrate by 5–10 mg/kg/week | 60 mg/kg/day | Monitor concomitant AED levels during titration VPA affects levels of lamotrigine, phenytoin, phenobarbital |
| Absence seizures | 15 mg/kg/day | Increase by 5–10 mg/kg/week until seizure control or limiting side effects | 60 mg/kg/day | Target plasma level 50–100 mcg/mL First-line for absence seizures per ILAE guidelines |
| Migraine prophylaxis | 250 mg BID (DR) or 500 mg daily (ER) | 500–1000 mg/day | 1000 mg/day | No evidence that higher doses improve efficacy Contraindicated in pregnancy and WOCBP without effective contraception |
The generally accepted therapeutic range is 50–100 mcg/mL for epilepsy and 50–125 mcg/mL for acute mania. Because valproic acid exhibits saturable protein binding, total concentrations rise less than proportionally with dose increases (nonlinear pharmacokinetics). Free (unbound) levels may be more clinically relevant, especially in patients with hypoalbuminaemia, renal impairment, pregnancy, or polypharmacy. The probability of thrombocytopenia increases significantly at total trough concentrations above 110 mcg/mL in females and 135 mcg/mL in males (FDA PI).
Reduce starting dose due to decreased unbound clearance and increased sensitivity to somnolence. Titrate more slowly with regular monitoring of fluid and nutritional intake. Consider dose reduction or discontinuation if the patient develops excessive somnolence or decreased food/fluid intake.
Pharmacology
Mechanism of Action
Valproic acid has multiple proposed mechanisms of action, though no single pathway fully explains its broad-spectrum efficacy. It increases brain concentrations of gamma-aminobutyric acid (GABA) through inhibition of GABA-transaminase and enhancement of GABA synthesis. Valproic acid also blocks voltage-gated sodium channels in a use-dependent fashion (similar to phenytoin and carbamazepine) and reduces T-type calcium currents in thalamic neurons, which is thought to underlie its efficacy in absence seizures. Additional mechanisms include modulation of dopaminergic and serotonergic neurotransmission, inhibition of histone deacetylase (HDAC) activity, and effects on intracellular signalling pathways involving protein kinase C and the inositol pathway, which may contribute to its mood-stabilising properties.
ADME Profile
| Parameter | Value | Clinical Implication |
|---|---|---|
| Absorption | Bioavailability ~100% (oral solution, capsules); 80–90% for ER; Tmax: 1–2 h (solution), 3–6 h (enteric-coated), 10–12 h (ER) | Completely absorbed from standard formulations; ER formulation allows once-daily dosing but with lower bioavailability |
| Distribution | Vd 0.1–0.4 L/kg; protein binding 90–95% to albumin (saturable — becomes nonlinear above ~50 mcg/mL); crosses placenta; enters breast milk (1–10% maternal level) | Small Vd due to high protein binding; saturable binding causes nonlinear PK; unbound fraction increases at higher concentrations and in hypoalbuminaemia |
| Metabolism | Hepatic: glucuronidation (~50% via UGT1A6, UGT2B7), mitochondrial β-oxidation (~40%), CYP-mediated oxidation (~10%, via CYP2C9, CYP2C19, CYP2A6); >10 metabolites identified; 4-en-VPA metabolite potentially hepatotoxic | No single dominant CYP pathway; inhibits UGT (increases lamotrigine), CYP2C9 (increases phenytoin free fraction), and epoxide hydrolase (increases CBZ-epoxide) |
| Elimination | t½ 9–16 h monotherapy (adults); 6–8 h with enzyme inducers; 6–9 h in children; total clearance 5–10 mL/min; <5% excreted unchanged in urine | Shorter half-life in children and with enzyme-inducing comedications; requires BID–TID dosing for IR formulations |
Side Effects
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Nausea | 22% (mania trials; vs 15% placebo) | Often transient; administer with food or use enteric-coated/ER formulations to reduce GI effects |
| Somnolence | 19% (mania trials; vs 12% placebo) | Dose-related; more prominent in elderly and with polypharmacy; consider dose reduction |
| Tremor | 25% (adjunctive epilepsy; up to 57% at high monotherapy doses) | Dose-related; may be managed with dose reduction; differentiate from worsening of underlying condition |
| Headache | ~31% (epilepsy monotherapy) | Common across all indications; similar to placebo rates in some studies |
| Dizziness | 12% (mania; vs 4% placebo) | Usually transient; assess fall risk in elderly |
| Vomiting | 12% (mania; vs 6% placebo) | Most common early in treatment; improves with continued therapy or ER formulation |
| Asthenia / fatigue | 10–27% | More common early in therapy, at higher doses, and in adjunctive epilepsy trials |
| Thrombocytopenia | 27% (at ~50 mg/kg/day in monotherapy trial) | Dose-related; risk increases significantly at trough levels >110 mcg/mL (F) or >135 mcg/mL (M); half normalise without dose change |
| Adverse Effect | Incidence | Clinical Note |
|---|---|---|
| Alopecia | 6% (leading cause of discontinuation in migraine trials) | Usually reversible; hair may regrow with different texture; zinc and selenium supplementation sometimes used |
| Weight gain | 2–8% | Can be significant (5–10 kg); metabolic monitoring recommended; common reason for non-adherence |
| Abdominal pain | 9% (mania; vs 8% placebo) | Investigate if persistent — exclude pancreatitis in severe or worsening cases |
| Diarrhoea | 5–12% | GI effects are among the most common tolerability concerns |
| Dyspepsia | 9% (mania; vs 8% placebo) | Take with food; enteric-coated formulations may reduce GI irritation |
| Rash | 6% (mania; vs 3% placebo) | Usually benign; distinguish from DRESS or serious dermatologic reactions |
| Adverse Effect | Estimated Frequency | Typical Onset | Required Action |
|---|---|---|---|
| Hepatotoxicity (BOXED WARNING) | Rare but fatal cases reported; highest risk in children <2 yr | Usually first 6 months | LFTs before and frequently during first 6 months; discontinue immediately if significant hepatic dysfunction |
| Teratogenicity (BOXED WARNING) | ~4-fold increased malformation rate; 8–11 point IQ reduction | In utero exposure, especially first trimester | Contraindicated for migraine in pregnancy/WOCBP without contraception; last resort for epilepsy/bipolar; mandatory pregnancy counselling |
| Pancreatitis (BOXED WARNING) | 2 cases/2,416 patients in trials; includes fatal hemorrhagic cases | Any time (initial use to years of therapy) | Evaluate promptly for abdominal pain/nausea/vomiting; discontinue if diagnosed; recurs on rechallenge |
| Hyperammonemia / hyperammonemic encephalopathy | Common (ammonia elevation); encephalopathy uncommon | Variable; increased risk with topiramate | Check ammonia if unexplained lethargy, vomiting, mental status changes; screen for UCD before initiation if risk factors present |
| DRESS / Multiorgan hypersensitivity | Rare (postmarketing) | Weeks after initiation | Discontinue unless alternate etiology established |
| Suicidality (AED class effect) | 0.43% (vs 0.24% placebo) | As early as 1 week | Monitor for depression, suicidal thoughts, mood changes |
| Hypothermia | Uncommon; increased with topiramate | Variable | Investigate for concurrent hyperammonemia; monitor core temperature |
Weight gain is one of the most clinically significant long-term tolerability concerns with valproic acid, affecting both adherence and metabolic health. Monitor weight and metabolic parameters (fasting glucose, lipid profile) at baseline and periodically. Dietary counselling and exercise programmes should be initiated early. If weight gain becomes clinically problematic and alternative agents exist, consider switching to a weight-neutral AED or mood stabiliser.
Drug Interactions
Valproic acid is both a victim and perpetrator of numerous drug interactions. It inhibits UGT glucuronidation (affecting lamotrigine), CYP2C9 (affecting phenytoin), and epoxide hydrolase (increasing carbamazepine-10,11-epoxide). Its own clearance is increased by hepatic enzyme inducers and decreased by enzyme inhibitors. Protein-binding displacement interactions are also clinically relevant because valproic acid is highly protein bound with saturable kinetics.
Monitoring
- Liver Function TestsBaseline, then frequently for 6 months
RoutinePerform LFTs before therapy and at frequent intervals during the first 6 months. Hepatotoxicity risk is highest in children under 2, patients on polytherapy, and those with mitochondrial disorders. Discontinue immediately if significant hepatic dysfunction is suspected. Note: LFTs may not always be abnormal before liver failure — also monitor clinical status (malaise, weakness, lethargy, facial oedema, anorexia, vomiting). - VPA Trough LevelAt steady state and after dose changes
RoutineDraw trough level just before next dose. Target 50–100 mcg/mL (epilepsy) or 50–125 mcg/mL (mania). Consider free VPA level in hypoalbuminaemia, renal failure, pregnancy, or polypharmacy. Risk of thrombocytopenia increases above 110 mcg/mL (F) or 135 mcg/mL (M). - CBC with PlateletsBaseline, then periodically
RoutineMonitor for dose-related thrombocytopenia (27% incidence at ~50 mg/kg/day), leucopenia, and coagulation abnormalities. Obtain before planned surgery and during pregnancy. Also check coagulation parameters (fibrinogen, PT) if bruising or bleeding develops. - Ammonia LevelIf symptomatic
Trigger-basedMeasure ammonia if unexplained lethargy, vomiting, or changes in mental status develop. Particularly important with concomitant topiramate. Screen for urea cycle disorders before initiation if risk factors present (unexplained encephalopathy, protein avoidance, family history). - Pregnancy TestingBefore initiation in WOCBP
RoutineConfirm negative pregnancy test before starting VPA in all women of childbearing potential. Verify effective contraception is in place. Counsel on teratogenic risks at every visit. For migraine, VPA is absolutely contraindicated in pregnancy and WOCBP not using effective contraception. - Weight & Metabolic ParametersBaseline, then every 3–6 months
RoutineWeight gain is a common long-term effect. Monitor weight, fasting glucose, and lipid panel at baseline and periodically. Address early with dietary and lifestyle interventions.
Contraindications & Cautions
Absolute Contraindications
- Hepatic disease or significant hepatic dysfunction
- Known POLG mutations (e.g., Alpers-Huttenlocher Syndrome) — high risk of fatal valproate-induced liver failure
- Suspected POLG-related disorder in children under 2 years
- Known hypersensitivity to valproic acid, divalproex sodium, or sodium valproate
- Known urea cycle disorders — risk of fatal hyperammonemic encephalopathy
- Migraine prophylaxis in pregnant women or WOCBP not using effective contraception
Relative Contraindications (Specialist Input Recommended)
- Women of childbearing potential requiring treatment for epilepsy or bipolar disorder — VPA should only be used if other medications have failed or are otherwise unacceptable; effective contraception mandatory; documented risk-benefit discussion required
- Children under 2 years — considerably increased risk of fatal hepatotoxicity; if used, should be sole agent
Use with Caution
- Patients on multiple anticonvulsants — increased hepatotoxicity risk
- Elderly patients — reduced unbound clearance; increased somnolence sensitivity
- Patients with congenital metabolic disorders or organic brain disease
- Patients taking topiramate — hyperammonemia and hypothermia risk
- Patients requiring surgery — check platelets and coagulation parameters pre-operatively
Fatal hepatic failure has occurred in patients receiving valproate, usually during the first 6 months of treatment. Children under 2 years, especially those on multiple anticonvulsants or with congenital metabolic disorders, are at considerably increased risk. Patients with mitochondrial disorders caused by POLG mutations are at particularly high risk. Monitor LFTs before therapy and frequently thereafter.
Valproate causes major congenital malformations, particularly neural tube defects (e.g., spina bifida), at a rate approximately 4 times higher than other AED monotherapies. It also causes decreased IQ scores (mean 8–11 points lower) and neurodevelopmental disorders following in utero exposure. Contraindicated for migraine in pregnancy. For epilepsy and bipolar disorder, use only if alternatives have failed. Folic acid supplementation is recommended but has not been proven to mitigate valproate-specific teratogenic risk.
Life-threatening pancreatitis, including fatal hemorrhagic cases, has been reported in both children and adults receiving valproate. Cases have occurred shortly after initiation as well as after years of use (2 cases in 2,416 patients in trials). Discontinue valproate if pancreatitis is diagnosed. The condition has recurred on rechallenge.
Patient Counselling
Purpose of Therapy
Valproic acid helps control seizures, stabilise mood in bipolar disorder, or prevent migraine headaches depending on the reason it was prescribed. It works by calming overactive electrical and chemical signals in the brain. It must be taken consistently as prescribed for maximum benefit.
How to Take
Depakote (delayed-release) tablets should be swallowed whole — do not crush or chew. Depakote ER (extended-release) must also be swallowed whole and is usually taken once daily. Sprinkle capsules can be opened and sprinkled on soft food. Take with food to reduce stomach upset. If a dose is missed, take it as soon as remembered unless it is nearly time for the next dose — never double up.
Sources
- AbbVie Inc. DEPAKOTE (divalproex sodium) delayed-release tablets prescribing information. Revised 05/2025. Reference ID: 5583194. FDA LabelPrimary regulatory source for all indications, dosing, boxed warnings, adverse reactions, and pharmacokinetics cited in this monograph.
- AbbVie Inc. DEPAKOTE ER (divalproex sodium) extended-release tablets prescribing information. FDA LabelER formulation PI with once-daily dosing guidance for mania, epilepsy, and migraine prophylaxis.
- Bowden CL, Brugger AM, Swann AC, et al. Efficacy of divalproex vs lithium and placebo in the treatment of mania. JAMA. 1994;271(12):918–924. DOIPivotal 3-week RCT establishing efficacy of divalproex for acute mania compared with lithium and placebo.
- Harden CL, Meador KJ, Pennell PB, et al. Practice parameter update: management issues for women with epilepsy. Neurology. 2009;73(2):133–141. DOIAAN practice parameter addressing teratogenicity data and management of antiepileptic drugs in women of childbearing potential.
- Meador KJ, Baker GA, Browning N, et al. Fetal antiepileptic drug exposure and cognitive outcomes at age 6 years (NEAD study). Lancet Neurol. 2013;12(3):244–252. DOIKey prospective study demonstrating lower IQ scores (mean 97) in children with in utero valproate exposure vs lamotrigine (108), carbamazepine (105), and phenytoin (108).
- Glauser T, Ben-Menachem E, Bourgeois B, et al. Updated ILAE evidence review of antiepileptic drug efficacy and effectiveness as initial monotherapy for epileptic seizures and syndromes. Epilepsia. 2013;54(3):551–563. DOIILAE guideline supporting valproate as a first-line option for generalised and absence seizures.
- Yatham LN, Kennedy SH, Parikh SV, et al. Canadian Network for Mood and Anxiety Treatments (CANMAT) and International Society for Bipolar Disorders (ISBD) 2018 guidelines. Bipolar Disord. 2018;20(2):97–170. DOIInternational guideline recommending divalproex as a first-line option for acute mania.
- Löscher W. Basic pharmacology of valproate: a review after 35 years of clinical use for the treatment of epilepsy. CNS Drugs. 2002;16(10):669–694. DOIComprehensive review of valproic acid’s multiple mechanisms of action including GABA enhancement, sodium channel blockade, and T-type calcium current reduction.
- Perucca E. Pharmacological and therapeutic properties of valproate: a summary after 35 years of clinical experience. CNS Drugs. 2002;16(10):695–714. DOIDetailed review of valproate pharmacokinetics including protein-binding saturation, nonlinear PK, and drug interactions.
- Zaccara G, Messori A, Moroni F. Clinical pharmacokinetics of valproic acid — 1988. Clin Pharmacokinet. 1988;15(6):367–389. DOIClassic PK review establishing volume of distribution (0.1–0.4 L/kg), half-life ranges, and metabolic pathway contributions.
- Methaneethorn J. A systematic review of population pharmacokinetics of valproic acid. Br J Clin Pharmacol. 2018;84(5):816–834. DOISystematic review of 23 population PK studies covering covariates affecting VPA clearance across age groups and clinical settings.