Bamifylline similar to theophylline and caffeine is a competitive inhibitor of the cyclic nucleotide phosphodiesterase V

Bamifylline was found to be a poor inhibitor of 3',5'-cyclic GMP phosphodiesterase (PDE V) as other methylxanthines such as teophylline and caffeine, The IC50 was respectively 3.24, 2.91, 1.69 mM. Inhibition decreased at higher cGMP concentrations. Lineweaver-Burk plots were linear or nearly linear, Differences in the actions of these inhibitors presumably reflect differences in the molecular requirements for effective interaction at the catalytic site on phosphodiesterase.