Fesoterodine and Darunavir Interaction

Drug interaction information between Fesoterodine and Darunavir.

Fesoterodine and Darunavir have a documented major interaction in FDA labeling.

FDA drug labeling documents a major-severity interaction between Fesoterodine and Darunavir. 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

Fesoterodine

Anticholinergic (Overactive Bladder)

Drug B

Darunavir

HIV Protease Inhibitor

How They Interact

Darunavir interferes with the way your body clears fesoterodine, leading to higher levels of the medication in your blood.

FDA Label Information

Urinary antispasmodics fesoterodine ↑ fesoterodine When fesoterodine is co-administered with darunavir/ritonavir, do not exceed a fesoterodine dose of 4 mg once daily.

Frequently Asked Questions

What SPL severity band is on file for Fesoterodine + Darunavir?

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?

Darunavir has 101 labeled pairs on file vs Fesoterodine's 15. In the major band specifically: Fesoterodine has 2 (also Itraconazole); Darunavir has 15 (also Lovastatin, Sildenafil, Lurasidone, Pimozide).

What mechanism field is on file for Fesoterodine and Darunavir?

Darunavir interferes with the way your body clears fesoterodine, leading to higher levels of the medication in your blood.

Darunavir carries more major-labeled pairs than Fesoterodine

SPL source-record counts only. This page's band is major · classes on file: Fesoterodine (Anticholinergic (Overactive Bladder)); Darunavir (HIV Protease Inhibitor).

Darunavir has 15 major-labeled pairs vs Fesoterodine's 2.

Fesoterodine

2 major · 2 moderate · 11 minor · 15 total

Darunavir

15 major · 16 moderate · 70 minor · 101 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.