Phosphodiesterase Inhibitors and their Role in Therapeutics

Phosphodiesterase (PDE) inhibitors are the drugs that block various isoforms of the enzyme phosphodiesterase - the enzyme causing metabolism of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in various tissues. The inhibition of PDE enzyme leads to accumulation of cAMP and cGMP in the cells, and these in turn lead to the therapeutic effects. Till date, 11 isoforms of PDE enzyme (PDE 1-PDE11) have been isolated, but the drugs that have been developed so far, are mostly selective inhibitors of PDE3, 4 and 5 isoforms or are non-selective inhibitors. Therapeutic potential of PDE inhibitors ranges from bronchodilatation to congestice heart failure to erectile dysfunction. Recently they have been shown to be effective in pulmonary arterial hypertension. This articles deals with various PDE inhibitors and their therapeutic indications.