Phosphodiesterase inhibitor

Phosphodiesterase inhibitor is a type of drug that blocks one or more of the five subtypes of the enzyme phosphodiesterase (PDE), thereby preventing the inactivation of the intracellular second messengers, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) by the respective PDE subtype(s). The ubiquity of the enzyme type means that non-specific inhibitors have a wide range of actions and side effects, while more selective inhibitors are less so.

Mechanism of Action

Phosphodiesterase inhibitors work by blocking the phosphodiesterase enzyme, which is responsible for breaking down cAMP and cGMP. By preventing this breakdown, the levels of these messengers increase in the body, leading to various physiological effects.

Types of Phosphodiesterase Inhibitors

There are several types of phosphodiesterase inhibitors, each with their own specific uses and mechanisms of action. These include:

• PDE5 inhibitors: These are used primarily for treating erectile dysfunction and pulmonary hypertension.
• PDE4 inhibitors: These are used for treating inflammatory diseases such as asthma and COPD.
• PDE3 inhibitors: These are used for treating heart failure and other cardiovascular conditions.

Side Effects

Like all drugs, phosphodiesterase inhibitors can have side effects. These can vary depending on the specific type of inhibitor, but may include headache, dizziness, flushing, and nausea. More serious side effects can include heart attack, stroke, and priapism.

See Also

• Drug
• Enzyme
• Erectile dysfunction
• Pulmonary hypertension
• Asthma
• COPD
• Heart failure

• 
  Phosphodiesterase-5 structure
• 
  PDE4-inhibiting thalidomide analogs