Final answer:
Phosphodiesterase inhibitors are a class of medications that block the action of the enzyme phosphodiesterase. Examples include sildenafil (Viagra), tadalafil (Cialis), and sildenafil (Revatio).
Step-by-step explanation:
Phosphodiesterase inhibitors are a class of medications that block the action of the enzyme phosphodiesterase. These medications are used for various medical conditions, including erectile dysfunction, pulmonary hypertension, and chronic obstructive pulmonary disease (COPD). Some examples of phosphodiesterase inhibitor medications include sildenafil (Viagra), tadalafil (Cialis), and sildenafil (Revatio). These medications work by relaxing and dilating blood vessels, allowing increased blood flow to certain areas of the body.