Recent Advances Using Phosphodiesterase 4 (PDE4) Inhibitors to Treat Inflammatory Disorders: Animal and Clinical Studies

Phosphodiesterase 4 (PDE4) inhibitors can be effective drugs for treating inflammation in different tissues/organs caused by conditions such as asthma, chronic obstructive pulmonary disease (COPD), psoriasis, and Alzheimer’s disease. It has been demonstrated that PDE4 inhibitors used for drug therapy provide some advantages over conventional formulations, including sensitivity to selective inhibitors, unique tissue distribution, and ease of oral administration. To date, the U.S. Food and Drug Administration (USFDA) had approved two PDE4 inhibitors, roflumilast (Daxas®, Daliresp®) and apremilast (Otezla®), for treating respective COPD and plaque psoriasis. Several pharmaceutical companies and academic laboratories continuously develop novel PDE4 inhibitors for clinical application. A concern pertaining to the development of PDE4 inhibitors is the high occurrence rate of side effects such as emesis, nausea, and headache. This review describes recent developments using PDE4 inhibitors for inflammation management. Special attention is paid to the use of PDE4 inhibitors in treating pulmonary and cutaneous inflammation. This review article focuses on issues related to animal and human studies. The action mode of the inhibitors is also addressed. Keywords: Phosphodiesterase 4 inhibitor, cyclic adenosine monophosphate, inflammation, chronic obstructive pulmonary disease, psoriasis.