What the FDA labels say about taking them together
Divalproex and lamotrigine
Divalproex's FDA label of March 31, 2026 names lamotrigine in its drug interactions section, and lamotrigine's label names divalproex too. The divalproex label: “… exposure to the other antiepileptic drug monotherapy treatments evaluated: lamotrigine (108 [95% CI 105–110]), carbamazepine (105 [95% CI 102–108]), and phenytoin (108 [95% CI 104–112]).”
Check it at the source: the divalproex FDA label on DailyMed (effective March 31, 2026, AbbVie Inc.); the lamotrigine FDA label on DailyMed (effective October 10, 2025).
What does the divalproex label say about lamotrigine?
Divalproex label, drug interactionsMonitoring of valproate concentrations is recommended ( 7.1 ) Co-administration of valproate can affect the pharmacokinetics of other drugs (e.g., diazepam, ethosuximide, lamotrigine, phenytoin) by inhibiting their metabolism or protein binding displacement ( 7.2 ) Patients stabilized on rufinamide should begin valproate therapy at a low dose, and titrate to clinically effective dose ( 7.2 ) Dosage adjustment of amitriptyline/nortriptyline, propofol, warfarin, and zidovudine may be necessary if used concomitantly with Depakote ( 7.2 ) Topiramate:
Divalproex label, warnings and precautionsThe largest of these studies 1 is a prospective cohort study conducted in the United States and United Kingdom that found that children with prenatal exposure to valproate (n=62) had lower IQ scores at age 6 (97 [95% CI 94-101]) than children with prenatal exposure to the other antiepileptic drug monotherapy treatments evaluated: lamotrigine (108 [95% CI 105–110]), carbamazepine (105 [95% CI 102–108]), and phenytoin (108 [95% CI 104–112]).
Source: FDA drug label (Depakote), AbbVie Inc., effective March 31, 2026 (SPL set 08a65cf4-7749-4ceb-6895-8f4805e2b01f), via openFDA; the full label on DailyMed
What does the lamotrigine label say about divalproex?
Lamotrigine label, boxed warningIn addition to age, factors that may increase the risk of occurrence or the severity of rash caused by LAMICTAL include (1) coadministration of LAMICTAL with valproate (includes valproic acid and divalproex sodium), (2) exceeding the recommended initial dose of LAMICTAL, (3) exceeding the recommended dose escalation for LAMICTAL, or (4) the presence of the HLA-B*1502 allele.
Source: FDA drug label (Lamictal Xr, NDA022115), GlaxoSmithKline LLC, effective October 10, 2025 (SPL set 3e2c9a35-6a39-41d7-ad84-3c0bb8894b09), via openFDA
Source: FDA drug label (Subvenite, NDA218879), OWP Pharmaceuticals, Inc., effective June 4, 2026 (SPL set 022b0913-f683-4af8-a862-f81b315909b2), via openFDA
Source: FDA drug label (LAMICTAL), GlaxoSmithKline LLC, effective October 10, 2025 (SPL set d7e3572d-56fe-4727-2bb4-013ccca22678), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Divalproex | Lamotrigine | |
|---|---|---|
| Labeled for | Bipolar disorder, Migraine, Seizures and epilepsy | Seizures and epilepsy, Bipolar disorder |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.194 per tablet 500 mg tablet | $0.0268 per tablet 25 mg tablet |
| Shortage now | No current entry | A presentation being discontinued |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once