Tadalafil is a phosphodiesterase inhibitor currently approved for use in erectile dysfunction (ED), benign prostatic hyperplasia (BPH), and pulmonary arterial hypertension (PAH). While tadalafil’s benefits in ED and BPH have been well-established for years, its benefits in PAH were identified only recently in major clinical trials, resulting in the recent approval of a single tablet, combination therapy of tadalafil with an endothelin receptor antagonist for PAH. With Tadalafil’s cardiovascular benefits in ED, BPH, and PAH, clinical researchers have begun investigating...