Azithromycin and Phenytoin Interaction
Drug interaction information between Azithromycin and Phenytoin.
Azithromycin and Phenytoin have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Azithromycin 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
While not proven in clinical trials, azithromycin might interfere with how your body handles phenytoin.
FDA Label Information
7.3 Potential Drug-Drug Interaction with Macrolides Interactions with digoxin, colchicine or phenytoin have not been reported in clinical trials with azithromycin. Until further data are developed regarding drug interactions when digoxin, colchicine or phenytoin are used with azithromycin careful monitoring of patients is advised.
Azithromycin Also Interacts With
- Theophylline major
- Warfarin minor
- Digoxin minor
- Colchicine minor
- Desloratadine 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 Azithromycin + Phenytoin?
Compiled FDA labeling labels this pair minor. 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 Azithromycin's 9. In the minor band specifically: Azithromycin has 8 (also Warfarin, Digoxin, Colchicine, Desloratadine); Phenytoin has 120 (also Atorvastatin, Omeprazole, Simvastatin, Methylphenidate).
What mechanism field is on file for Azithromycin and Phenytoin?
While not proven in clinical trials, azithromycin might interfere with how your body handles phenytoin.
Phenytoin carries more major-labeled pairs than Azithromycin
SPL source-record counts only. This page's band is minor · classes on file: Azithromycin (Macrolide Antibiotic); Phenytoin (Anticonvulsant (Hydantoin)).
Phenytoin has 4 major-labeled pairs vs Azithromycin's 1. This page itself is in the minor band, not the major band.
1 major · 0 moderate · 8 minor · 9 total
- Other minor peers for Azithromycin
- Warfarin
- Digoxin
- Colchicine
- Desloratadine
4 major · 23 moderate · 120 minor · 147 total
- Other minor peers for Phenytoin
- Atorvastatin
- Omeprazole
- Simvastatin
- Methylphenidate
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.