Zardaverine is a selective inhibitor of phosphodiesterase types 3 and 4 (PDE3 and PDE4). As a PDE4 inhibitor, it is primarily known for its application in research focused on inflammatory diseases, particularly those affecting the respiratory system, such as asthma and chronic obstructive pulmonary disease (COPD). It reduces inflammation by inhibiting the breakdown of cyclic AMP, which helps in relaxing smooth muscles and modulating inflammatory responses. As a PDE3 inhibitor, it has been explored for its vasodilatory effects and potential in cardiovascular conditions by promoting blood vessel dilation and improving circulation. Additionally, zardaverine has been studied in preclinical research for therapeutic effects in other inflammatory and autoimmune disorders. Its role in modulating cellular signaling pathways makes it a compound of interest in pharmacological research. Usage remains in the experimental stage, requiring further studies for efficacy and safety in humans.