Nirmatrelvir/Ritonavir and Carbamazepine Interaction

Drug interaction information between Nirmatrelvir/Ritonavir and Carbamazepine.

Nirmatrelvir/Ritonavir and Carbamazepine have a documented major interaction in FDA labeling.

FDA drug labeling documents a major-severity interaction between Nirmatrelvir/Ritonavir and Carbamazepine. This page displays the available source-record category and label text. The category is not an individual risk estimate or medication-combination direction.

Drug A

Nirmatrelvir/Ritonavir

Antiviral (Protease Inhibitor Combination)

Drug B

Carbamazepine

Anticonvulsant

How They Interact

Carbamazepine makes your body get rid of the antiviral medicine too quickly, which prevents it from working against the virus.

FDA Label Information

Anticonvulsants carbamazepine , phenobarbital, primidone, phenytoin ↓ nirmatrelvir/ritonavir Co-administration contraindicated due to potential loss of virologic response and possible resistance [see Contraindications (4) ] .

Carbamazepine Also Interacts With

View all Carbamazepine interactions →

Frequently Asked Questions

What SPL severity band is on file for Nirmatrelvir/Ritonavir + Carbamazepine?

Compiled FDA labeling labels this pair major. That is a source-record field, not an individual medication-combination decision.

Which drug in this pair has the larger labeled-interaction portfolio?

Carbamazepine has 129 labeled pairs on file vs Nirmatrelvir/Ritonavir's 86. In the major band specifically: Nirmatrelvir/Ritonavir has 23 (also Simvastatin, Lovastatin, Sildenafil, Rifampin); Carbamazepine has 3 (also Ranolazine, Risperidone).

What mechanism field is on file for Nirmatrelvir/Ritonavir and Carbamazepine?

Carbamazepine makes your body get rid of the antiviral medicine too quickly, which prevents it from working against the virus.

Nirmatrelvir/Ritonavir carries more major-labeled pairs than Carbamazepine

SPL source-record counts only. This page's band is major · classes on file: Nirmatrelvir/Ritonavir (Antiviral (Protease Inhibitor Combination)); Carbamazepine (Anticonvulsant).

Nirmatrelvir/Ritonavir has 23 major-labeled pairs vs Carbamazepine's 3.

Nirmatrelvir/Ritonavir

23 major · 30 moderate · 33 minor · 86 total

Carbamazepine

3 major · 16 moderate · 110 minor · 129 total

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.