Viagra may aggravate severe apnoea

Sildenafil (Viagra) taken at bedtime may worsen breathing problems in patients with severe obstructive sleep apnoea. Obstructive sleep apnoea is a common problem that occurs when the soft tissues at the back of the throat collapse and close off the airway during sleep, resulting in brief moments in which breathing stops. Impotence, also known as erectile dysfunction, is highly prevalent in patients with obstructive sleep apnoea. However, sildenafil prolongs the action of nitric oxide, which promotes upper airway congestion. The researchers from the Federal University of Sao Paulo, Brazil, examined the effects of a single 50 mg dose of sildenafil on the sleep pattern of 14 men (average age, 53 years) with severe obstructive sleep apnoea. The subjects were randomly assigned to receive sildenafil or a placebo (sugar pill) before they participated in an all-night sleep study, which included at least 7 hours of recording time). The subjects switched treatments and process was repeated the next night. It was found that compared with placebo, sildenafil led to a significantly increased desaturation index, the number of episodes of oxygen reduction per hour of recording time (30 events per hour versus 19 events per hour). There was also a significant increase in the percentage of total sleep time with an oxygen saturation of less than 90 percent (16 percent versus 8 percent) and a significant increase in the maximal duration of a desaturation event (73 versus 48 seconds). Sleep pattern was also altered by sildenafil use, with an increase in stage 2 (non-rapid eye movement) sleep compared with placebo and a decrease in deep sleep compared with the start of the study and placebo. Because of the small sample size, the results cannot be extrapolated to all obstructive sleep apnoea patients. Nevertheless, sildenafil should be used with caution for treating erectile dysfunction in individuals with a sleep-related breathing disorder.