Phosphodiesterase inhibitors (PDEIs) are a class of drugs that block one or more of the five subtypes of the enzyme phosphodiesterase, thereby preventing the inactivation of the secondary messenger cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). These enzymes play a crucial role in regulating cellular responses to hormones and neurotransmitters, affecting processes such as inflammation, cardiovascular function, and neurotransmission.
