What the FDA labels say about taking them together
Atazanavir and lamotrigine
Atazanavir's FDA label of August 6, 2025 names lamotrigine in its drug interactions section, and lamotrigine's label names atazanavir too. The lamotrigine label: “Decreased lamotrigine AUC approximately 32%.”
Check it at the source: the atazanavir FDA label on DailyMed (effective August 6, 2025, Aurobindo Pharma Limited); the lamotrigine FDA label on DailyMed (effective October 10, 2025).
What does the atazanavir label say about lamotrigine?
Atazanavir label, drug interactionsConcomitant Drug Class/Specific Drugs: lamotrigine; Effect on Concentration of Atazanavir or Concomitant Drug: ↓ lamotrigine; Clinical Comment: Coadministration of lamotrigine and atazanavir with ritonavir may require dosage adjustment of lamotrigine. No dose adjustment of lamotrigine is required when coadministered with atazanavir without ritonavir.
Source: FDA drug label (Reyataz, NDA021567), E.R. Squibb & Sons, L.L.C., effective December 5, 2024 (SPL set 165cff62-b284-4a27-a65d-9ec8a5bfcdd8), via openFDA
Source: FDA drug label (Atazanavir Sulfate), Aurobindo Pharma Limited, effective August 6, 2025 (SPL set 7fbea274-d6b5-4faa-bbf0-05fefab42114), via openFDA; the full label on DailyMed
What does the lamotrigine label say about atazanavir?
Lamotrigine label, drug interactionsConcomitant Drug: Atazanavir/ritonavir; Effect on Concentration of Lamotrigine or Concomitant Drug: ↓ lamotrigine; Clinical Comment: Decreased lamotrigine AUC approximately 32%.
Subvenite label (OWP Pharmaceuticals, Inc., June 4, 2026), drug interactionsDRUG INTERACTIONS Valproate increases lamotrigine concentrations more than 2-fold. ( 7 , 12.3 ) Carbamazepine, phenytoin, phenobarbital, primidone, and rifampin decrease lamotrigine concentrations by approximately 40%. ( 7 , 12.3 ) Estrogen-containing oral contraceptives decrease lamotrigine concentrations by approximately 50%. ( 7 , 12.3 ) Protease inhibitors lopinavir/ritonavir and atazanavir/lopinavir decrease lamotrigine exposure by approximately 50% and 32%, respectively. ( 7 , 12.3 ) Coadministration with organic cationic transporter 2 substrates with narrow therapeutic index is not recommended ( 7 , 12.3 ) Significant drug interactions with SUBVENITE are summarized in this section.
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
| Atazanavir | Lamotrigine | |
|---|---|---|
| Labeled for | HIV | Seizures and epilepsy, Bipolar disorder |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $2.23 per capsule 300 mg capsule | $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