Tadalafil and Terazosin interaction
Tadalafil and Terazosin: 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 Tadalafil (Cialis) label · effective 2026-06-03
…coadministration of an alpha-blocker and CIALIS for the treatment of BPH has not been adequately studied, and due to the potential vasodilatory effects of combined use resulting in blood pressure lowering, the combination of CIALIS and alpha-blockers is not recommended for the treatment of BPH. [see Dosage and Administration ( 2.7 ), Drug Interactions ( 7.1 ),…
Use of CIALIS with alpha-blockers, antihypertensives or substantial amounts of alcohol (≥5 units) may lead to hypotension ( 5.6 , 5.9 ).
CIALIS is not recommended in combination with alpha-blockers for the treatment of BPH because efficacy of the combination has not been adequately studied and because of the risk of blood pressure lowering.
Caution is advised when CIALIS is used as a treatment for ED in men taking alpha-blockers.
…Physicians should be aware that CIALIS for once daily use provides continuous plasma tadalafil levels and should consider this when evaluating the potential for interactions with medications (e.g., nitrates, alpha-blockers, anti-hypertensives and potent inhibitors of CYP3A4) and with substantial consumption of alcohol [see Drug Interactions ( 7.1 , 7.2 , 7.3 )] .
From the Terazosin (TEZRULY) label · effective 2025-04-18
Risk of Hypotension with Concomitant Use of Other Antihypertensive Agents and Phospodiesterase Type 5 Inhibitors (PDE5-I): Concomitant administration of TEZRULY with antihypertensives or phosphodiesterase-5 (PDE-5) inhibitors can result in additive blood pressure lowering effects and symptomatic hypotension (5.3).
Risk of Hypotension with Concomitant Use of Other Antihypertensive Agents and Phosphodiesterase Type 5 Inhibitors (PDE5-I) Concomitant use of TEZRULY with other anti-hypertensive agents, especially the calcium channel blocker verapamil, can increase the risk of hypotension.
Hypotension has been reported when terazosin has been used with phosphodiesterase-5 (PDE-5) inhibitors.
Therefore, PDE-5 inhibitor therapy should be initiated at the lowest dose in patients taking TEZRULY.
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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.