Severe anaemia, glaucoma, pregnancy, lactation, hypotension, increased intracranial pressure and idiosyncrasy to glyceryl trinitrate.
Glyceryl trinitrate should not be coadministered with Viagra (sildenafil citrate) and or other Phosphodiesterase Type 5 (PDE5) Inhibitors as this may potentiate the hypotensive effects of organic nitrates.