Two medicines, side by side
Carbamazepine vs valproic acid
Carbamazepine and valproic acid are both labeled for seizures and epilepsy. Drugs@FDA records approvals of carbamazepine since 1968 and of valproic acid since 1978. Pharmacies paid $0.119 per carbamazepine 200 mg tablet and $0.243 per valproic acid 250 mg capsule (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. How each works, in its label's words: Carbamazepine, “It appears to act by reducing polysynaptic responses and blocking the post-tetanic potentiation.”; Valproic acid, “Valproic acid dissociates to the valproate ion in the gastrointestinal tract.”
Check it at the source: the carbamazepine FDA label on DailyMed (effective August 20, 2026); the valproic acid FDA label on DailyMed (effective January 24, 2025).
Highlights of the carbamazepine record
Carbamazepine (Tegretol) · label of August 20, 2026
SERIOUS DERMATOLOGIC REACTIONS AND HLA-B*1502 ALLELE SERIOUS AND SOMETIMES FATAL DERMATOLOGIC REACTIONS, INCLUDING TOXIC EPIDERMAL NECROLYSIS (TEN) AND STEVENS-JOHNSON SYNDROME (SJS), HAVE BEEN REPORTED DURING TREATMENT WITH TEGRETOL. THESE REACTIONS ARE ESTIMATED TO OCCUR IN 1 TO 6 PER 10,000 NEW USERS IN COUNTRIES WITH MAINLY CAUCASIAN POPULATIONS, BUT THE RISK IN SOME ASIAN COUNTRIES IS ESTIMATED TO BE ABOUT 10 TIMES HIGHER.
Used for
From the label: indicationsEpilepsy Tegretol is indicated for use as an anticonvulsant drug. Evidence supporting efficacy of Tegretol as an anticonvulsant was derived from active drug-controlled studies that enrolled patients with the following seizure types: Partial seizures with complex symptomatology (psychomotor, temporal lobe). Patients with these seizures appear to show greater improvement than those with other types. […]
On the market
- Earliest approval on file
- March 11, 1968
- Generic labelers
- 42 labelers
- Pharmacy cost
- $0.119 per tablet
Supply and safety
- Shortage
- A presentation being discontinued
- Recalls
- 11
Highlights of the valproic acid record
Valproic acid (Depakene) · label of January 24, 2025
LIFE THREATENING ADVERSE REACTIONS WARNING: LIFE THREATENING ADVERSE REACTIONS See full prescribing information for complete boxed warning. Hepatotoxicity, including fatalities, usually during the first 6 months of treatment. Children under the age of two years and patients with mitochondrial disorders are at higher risk.
Used for
From the label: indicationsValproic acid is indicated for: Monotherapy and adjunctive therapy of complex partial seizures; sole and adjunctive therapy of simple and complex absence seizures; adjunctive therapy in patients with multiple seizure types that include absence seizures ( 1 ) 1.1 Epilepsy Valproic acid is indicated as monotherapy and adjunctive therapy in the treatment of patients with complex partial seizures that occur either in isolation or in association with other types of seizures. […]
On the market
- Earliest approval on file
- February 28, 1978
- Generic labelers
- 22 labelers
- Pharmacy cost
- $0.243 per capsule
Supply and safety
- Shortage
- Listed; available
- Recalls
- 2
Source: FDA drug labels via openFDA (Carbamazepine label of August 20, 2026, Valproic acid label of January 24, 2025); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do carbamazepine and valproic acid differ on the record?
How each works, in its label's words: Carbamazepine, “It appears to act by reducing polysynaptic responses and blocking the post-tetanic potentiation.”; Valproic acid, “Valproic acid dissociates to the valproate ion in the gastrointestinal tract.”
Both are in FDA's class mood stabilizers.
Half-life, in each label's words: Carbamazepine, “Initial half-life values range from 25 to 65 hours, decreasing to 12 to 17 hours on repeated doses.”; Valproic acid, “Mean terminal half-life for valproate monotherapy ranged from 9 to 16 hours following oral dosing regimens of 250 to …”
Both labels carry a boxed warning; the records quote them.
Generics: carbamazepine since 1986; valproic acid since 1986 (Drugs@FDA).
| Carbamazepine | Valproic acid | |
|---|---|---|
| Labeled for | Bipolar disorder, Seizures and epilepsy | Seizures and epilepsy, Migraine |
| Pharmacologic class | Mood Stabilizer | Anti-epileptic Agent, Mood Stabilizer |
| How it works (label) | Mechanism of Action Tegretol has demonstrated anticonvulsant properties in rats and mice with electrically and chemically induced seizures. It appears to act by reducing polysynaptic responses and blocking the post-tetanic potentiation. | Valproic acid dissociates to the valproate ion in the gastrointestinal tract. The mechanisms by which valproate exerts its therapeutic effects have not been established. |
| Half-life (label) | Initial half-life values range from 25 to 65 hours, decreasing to 12 to 17 hours on repeated doses. | Mean terminal half-life for valproate monotherapy ranged from 9 to 16 hours following oral dosing regimens of 250 to 1,000 mg. |
| Earliest approval on file (Drugs@FDA) | March 11, 1968 | February 28, 1978 |
| First generic approved | August 14, 1986 | February 28, 1986 |
| Generic labelers (NDC) | 42 labelers | 22 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.119 per tablet (Carbamazepine 200 mg tablet) | $0.243 per capsule (Valproic acid 250 mg capsule) |
| 12-month price change | +0.6% | -4% |
| Boxed warning | Yes | Yes |
| Shortage now | A presentation being discontinued | Listed; available |
| Recalls recorded | 11 | 2 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 66,615 | 51,380 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
Do their labels mention each other?
Carbamazepine label, drug interactionsAccordingly, the dosage of Tegretol should be adjusted and/or the plasma levels monitored when used concomitantly with loxapine, quetiapine, valproic acid, or brivaracetam.
Carbamazepine label, drug interactionsAccordingly, the dosage of Carbatrol should be adjusted and/or the plasma levels monitored when used concomitantly with loxapine, quetiapine, or valproic acid.
Valproic acid label, warnings and precautions… than children with prenatal exposure to the other antiepileptic drug monotherapy treatments evaluated: lamotrigine (108 [95% C.I. 105-110]), carbamazepine (105 [95% C.I. 102-108]), and phenytoin (108 [95% C.I. 104-112]).
Source: FDA drug labels via openFDA
What next?
- Alternatives to carbamazepine
- every medicine labeled for the same conditions