Sildenafil - Contraindications
These conditions, allergies, and situations mean Sildenafil should NOT be used. From the US FDA-approved drug label Section 4.
4 CONTRAINDICATIONS Administration of sildenafil tablets to patients using nitric oxide donors, such as organic nitrates or organic nitrites in any form.
Sildenafil citrate was shown to potentiate the hypotensive effect of nitrates ( 4.1 , 7.1 , 12.2 ) Known hypersensitivity to sildenafil or any component of tablet Administration with guanylate cyclase (GC) stimulators, such as riociguat 4.1 Nitrates Consistent with its known effects on the nitric oxide/cGMP pathway [ see Clinical Pharmacology ( 12.1 , 12.2 ) ], sildenafil citrate was shown to potentiate the hypotensive effects of nitrates, and its administration to patients who are using nitric oxide donors such as organic nitrates or organic nitrites in any form either regularly and/or intermittently is therefore contraindicated.
After patients have taken sildenafil tablets, it is unknown when nitrates, if necessary, can be safely administered.
Although plasma levels of sildenafil at 24 hours post dose are much lower than at peak concentration, it is unknown whether nitrates can be safely co-administered at this time point [ see Dosage and Administration , Drug Interactions , and Clinical Pharmacology ].
4.2 Hypersensitivity Reactions Sildenafil citrate is contraindicated in patients with a known hypersensitivity to sildenafil, as contained in sildenafil tablets and REVATIO, or any component of the tablet.
Hypersensitivity reactions have been reported, including rash and urticaria [ see Adverse Reactions ] .
4.3 Concomitant Guanylate Cyclase (GC) Stimulators Do not use sildenafil tablets in patients who are using a GC stimulator, such as riociguat.
PDE5 inhibitors, including sildenafil citrate, may potentiate the hypotensive effects of GC stimulators.