Dutasteride and tamsulosin and Verapamil interaction

Dutasteride and tamsulosin and Verapamil: the Dutasteride and tamsulosin prescribing label flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.

What the FDA labels say

From the Dutasteride and tamsulosin (Jalyn) label · effective 2026-03-09

Major

Drug-Drug Interactions Strong Inhibitors of Cytochrome P450 (CYP) 3A4 Tamsulosin-containing products, including JALYN, should not be coadministered with strong CYP3A4 inhibitors (e.g., ketoconazole) as this can significantly increase tamsulosin exposure [see Drug Interactions (7.1) , Clinical Pharmacology (12.3) ].

Warnings and precautionsby drug classView label on DailyMed
Major

Since CYP2D6 PMs cannot be readily identified and the potential for significant increase in tamsulosin exposure exists when tamsulosin 0.4 mg is coadministered with strong CYP3A4 inhibitors in CYP2D6 PMs, tamsulosin 0.4 mg capsules should not be used in combination wıth strong inhibitors of CYP3A4 (e.g., ketoconazole).

Drug interactionsby drug classView label on DailyMed
Moderate

Use caution in combination with moderate CYP3A4 inhibitors (e.g., erythromycin) or strong (e.g., paroxetine) or moderate CYP2D6 inhibitors, a combination of both CYP3A4 and CYP2D6 inhibitors, or known poor metabolizers of CYP2D6.

Warnings and precautionsby drug classView label on DailyMed
Moderate

Moderate Inhibitors of CYP3A4, Inhibitors of CYP2D6, or a Combination of Both CYP3A4 and CYP2D6 Inhibitors Tamsulosin-containing products, including JALYN, should be used with caution when coadministered with moderate inhibitors of CYP3A4 (e.g., erythromycin), strong (e.g., paroxetine) or moderate (e.g., terbinafine) inhibitors of CYP2D6, a combination of both…

Warnings and precautionsby drug classView label on DailyMed
Moderate

…potential for drug-drug interactions, use caution when prescribing a dutasteride-containing product, including JALYN, to patients taking potent, chronic CYP3A4 enzyme inhibitors (e.g., ritonavir) [see Clinical Pharmacology (12.3) ] Tamsulosin Strong and Moderate Inhibitors of CYP3A4 or CYP2D6: Tamsulosin is extensively metabolized, mainly by CYP3A4 or CYP2D6.

Drug interactionsby drug classView label on DailyMed

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Not 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.