Tadalafil for the treatment of pulmonary arterial hypertension

Abstract

Tadalafil is a selective inhibitor of phosphodiesterase type-5 (PDE-5) that was originally developed for the treatment of male erectile dysfunction and recently approved for the treatment of pulmonary arterial hypertension (PAH). The antipulmonary hypertensive effects of nitric oxide and the natriuretic peptides are mediated via increasing intracellular cGMP and enzymatic degradation by PDE-5 is the major route of cGMP inactivation in the lung. Evidence is accruing that PDE-5 activity is increased in pulmonary vascular diseases and may contribute to the pathogenesis of PAH. The longer half-life of tadalafil allows for once-daily dosing as compared with three-times daily dosing for sildenafil, the only other PDE-5 inhibitor currently approved for treatment of PAH. This article reviews the role of cGMP and PDE-5 in PAH, presents the results of recent clinical trials and discusses the role of tadalafil in the treatment of this rare but difficult-to-treat disease.

Keywords::

• cGMP
• natriuretic peptide
• nitric oxide
• phosphodiesterase inhibitor
• phosphodiesterase type-5
• primary pulmonary hypertension
• pulmonary arterial hypertension
• pulmonary hypertension treatment
• tadalafil

Financial & competing interests disclosure

James R Klinger is a consultant for Actelion, Bayer, BioMarin, Gilead and United Therapeutics, and is on the speakers bureau for Actelion, Gilead and United Therapeutics. He has received grant support from Actelion, Bayer, Gilead, Pfizer and United Therapeutics. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.