PDE inhibitors have been identified as new potential therapeutics in areas such as pulmonary arterial hypertension, coronary heart disease, dementia, depression, asthma, COPD, protozoal infections (including malaria) and schizophrenia.
PDE also are important in seizure incidence. For example, PDE compromised the antiepileptic activity of adenosine. In addition, using of a PDE inhibitor (pentoxifylline) in pentylenetetrazole-induced seizure indicated the antiepileptic effect by increasing the time latency to seizure incidence and decreasing the seizure duration in vivo.
Cilostazol (Pletal) inhibits PDE3. This inhibition allows red blood cells to be more able to bend. This is useful in conditions such as intermittent claudication, as the cells can maneuver through constricted veins and arteries more easily.
Dipyridamole inhibits PDE-3 and PDE-5. This leads to intraplatelet accumulation of cAMP and/or cGMP, inhibiting platelet aggregation.
Zaprinast inhibits the growth of asexual blood-stage malaria parasites (Plasmodium falciparum) in vitro with an ED value of 35 μM, and inhibits PfPDE1, a P. falciparum cGMP-specific phosphodiesterase, with an IC value of 3.8 μM.
Xanthines such as caffeine and theobromine are cAMP-phosphodiesterase inhibitors. However, the inhibitory effect of xanthines on phosphodiesterases are only seen at dosages higher than what people normally consume.
Sildenafil, Tadalafil and Vardenafil are PDE-5 inhibitors and are widely used in the treatment of erectile dysfunction.