Isosorbide mononitrate and Tadalafil interaction
Isosorbide mononitrate and Tadalafil: 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 Isosorbide mononitrate label · effective 2019-11-01
Do not use isosorbide mononitrate in patients who are taking certain drugs for erectile dysfunction (phosphodiesterase inhibitors), such as sildenafil, tadalafil, or vardenafil.
Drug Interactions Concomitant use of isosorbide mononitrate with phosphodiesterase inhibitors in any form is contraindicated (see CONTRAINDICATIONS).
From the Tadalafil (Cialis) label · effective 2026-06-03
Administration of CIALIS to patients using any form of organic nitrate is contraindicated.
CIALIS was shown to potentiate the hypotensive effect of nitrates ( 4.1 ).
Nitrates Administration of CIALIS to patients who are using any form of organic nitrate, either regularly and/or intermittently, is contraindicated.
In clinical pharmacology studies, CIALIS was shown to potentiate the hypotensive effect of nitrates [see Clinical Pharmacology ( 12.2 )] .
In such a patient, who has taken CIALIS, where nitrate administration is deemed medically necessary for a life-threatening situation, at least 48 hours should have elapsed after the last dose of CIALIS before nitrate administration is considered.
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.