Ensifentrine

**Semantic type:** Pharmacologic Substance

**Definition:** An inhaled inhibitor of the phosphodiesterase (PDE) types 3 (PDE3) and 4 (PDE4), with potential anti-inflammatory and bronchodilator activities. Upon administration, ensifentrine targets, binds to and inhibits PDE3 and PDE4, which leads to an increase of both intracellular levels of cyclic-3',5'-adenosine monophosphate (cAMP) and cAMP-mediated signaling. This may lead to bronchial smooth muscle relaxation and modulate inflammatory responses. PDE3 and PDE4, members of the PDE superfamily, hydrolyze cAMP and 3',5'-cyclic guanosine monophosphate (cGMP) to their inactive 5' monophosphates. PDE3 is the most expressed PDE isoenzyme in bronchial smooth muscle. PDE4 is expressed in immune cells including T-cells, monocytes, macrophages, neutrophils, dendritic cells and eosinophils. It plays an important role in inflammation, especially in inflammatory airway diseases.

**Synonyms:** - ENSIFENTRINE - RPL 554 - RPL-554 - RPL554