Nirmatrelvir and ritonavir and Silodosin interaction
Nirmatrelvir and ritonavir and Silodosin: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Nirmatrelvir and ritonavir (Paxlovid) label · effective 2026-02-19
…colchicine (in patients with renal and/or hepatic impairment [see Table 2 , Drug Interactions (7.3)] ) • Antipsychotics: lurasidone, pimozide • Benign prostatic hyperplasia agents: silodosin • Cardiovascular agents: eplerenone, ivabradine • Ergot derivatives: dihydroergotamine, ergotamine, methylergonovine • HMG-CoA reductase inhibitors: lovastatin, simvastatin…
Benign prostatic hyperplasia agents silodosin ↑ silodosin Co-administration contraindicated due to potential for postural hypotension [see Contraindications (4) ] .
From the Silodosin label · effective 2026-03-16
Severe renal impairment (CCr < 30 mL/min) Severe hepatic impairment (Child-Pugh score ≥ 10) Concomitant administration with strong Cytochrome P450 3A4 (CYP3A4) inhibitors (e.g., ketoconazole, clarithromycin, itraconazole, ritonavir) [see DRUG INTERACTIONS (7.1) ] Patients with a history of hypersensitivity to silodosin or any of the ingredients in silodosin capsules…
Concomitant administration with strong Cytochrome P450 3A4 (CYP3A4) inhibitors (e.g., ketoconazole, clarithromycin, itraconazole, ritonavir).
Concomitant use of ketoconazole or other strong CYP3A4 inhibitors (e.g., itraconazole, clarithromycin, ritonavir) is therefore contraindicated [see DRUG INTERACTIONS (7.1) ].
Concomitant administration of strong CYP3A4 inhibitors and silodosin capsules is contraindicated [see CONTRAINDICATIONS (4) , WARNINGS AND PRECAUTIONS (5.4) and CLINICAL PHARMACOLOGY (12.3) ].
Pharmacokinetic Drug-Drug Interactions In a drug interaction study, co‑administration of a single 8 mg dose of silodosin capsules with 400 mg ketoconazole, a strong CYP3A4 inhibitor, caused a 3.8‑fold increase in maximum plasma silodosin concentrations and 3.2‑fold increase in silodosin exposure (i.e., AUC).
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.