Dolutegravir/Lamivudine and Phenytoin Interaction
Drug interaction information between Dolutegravir/Lamivudine and Phenytoin.
Dolutegravir/Lamivudine and Phenytoin have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Dolutegravir/Lamivudine and Phenytoin. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.
How They Interact
Phenytoin causes your body to clear dolutegravir more quickly, which reduces the amount of medicine available to fight the virus.
FDA Label Information
Anticonvulsants: Oxcarbazepine Phenytoin Phenobarbital ↓Dolutegravir Avoid coadministration with DOVATO because there are insufficient data to make dosing recommendations.
Dolutegravir/Lamivudine Also Interacts With
- Dofetilide major
- Metformin moderate
- Oxcarbazepine moderate
- Phenobarbital moderate
- Carbamazepine minor
Phenytoin Also Interacts With
- Nirmatrelvir/Ritonavir major
- Posaconazole major
- Ranolazine major
- Voriconazole major
- Apixaban moderate
Frequently Asked Questions
What SPL severity band is on file for Dolutegravir/Lamivudine + Phenytoin?
Compiled FDA labeling labels this pair moderate. That is a source-record field, not an individual medication-combination decision.
Which drug in this pair has the larger labeled-interaction portfolio?
Phenytoin has 147 labeled pairs on file vs Dolutegravir/Lamivudine's 9. In the moderate band specifically: Dolutegravir/Lamivudine has 4 (also Metformin, Oxcarbazepine, Phenobarbital); Phenytoin has 23 (also Apixaban, Aprepitant, Canagliflozin, Carbidopa/Levodopa).
What mechanism field is on file for Dolutegravir/Lamivudine and Phenytoin?
Phenytoin causes your body to clear dolutegravir more quickly, which reduces the amount of medicine available to fight the virus.
Phenytoin carries more major-labeled pairs than Dolutegravir/Lamivudine
SPL source-record counts only. This page's band is moderate · classes on file: Dolutegravir/Lamivudine (Integrase Inhibitor / NRTI Combination); Phenytoin (Anticonvulsant (Hydantoin)).
Phenytoin has 4 major-labeled pairs vs Dolutegravir/Lamivudine's 1. This page itself is in the moderate band, not the major band.
1 major · 4 moderate · 4 minor · 9 total
- Other moderate peers for Dolutegravir/Lamivudine
- Metformin
- Oxcarbazepine
- Phenobarbital
4 major · 23 moderate · 120 minor · 147 total
- Other moderate peers for Phenytoin
- Apixaban
- Aprepitant
- Canagliflozin
- Carbidopa/Levodopa
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. This registry does not provide individual medication-combination directions.
Read our methodology - how this data is sourced, computed, and verified.