Safety of sildenafil in the treatment of erectile dysfunction in patients with obstructive sleep apnoea.

Obstructive sleep apnoea, characterised by repetitive occlusion of the upper airway during sleep, is recognised as a risk or even an aetiological factor for erectile dysfunction. On the other hand, sleep-disordered breathing has been reported by many patients with erectile dysfunction. Sildenafil, a very commonly used erectile dysfunction treatment, could, at least theoretically, exacerbate sleep apnoea by interfering with pharyngeal muscle tone, nasal patency and gas exchange in the lung. A recent safety study suggested a detrimental effect of oral sildenafil on respiratory events in patients with obstructive sleep apnoea. Given the inconclusiveness of evidence on pathophysiological mechanisms and the paucity of relevant clinical data the safety risk of sildenafil administration in patients with obstructive sleep apnoea should be questioned. More clinical trials are needed to clarify this issue.