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A double-blind, placebo-controlled, crossover study of sildenafil in obstructive sleep apnea.

Roizenblatt S, Guilleminault C, Poyares D, Cintra F, Kauati A, Tufik S

Department of Psychobiology, Federal University of São Paulo, São Paulo, Brazil. suelyroi@psicobio.epm.br

BACKGROUND: Sildenafil prolongs the action of cyclic guanosine monophosphate and nitric oxide by inhibiting cyclic guanosine monophosphate-specific phosphodiesterase 5. It is largely used for erectile dysfunction, a highly prevalent condition in obstructive sleep apnea. Because nitric oxide promotes upper airway congestion, muscle relaxation, and pulmonary vasodilation, the aim of this study was to establish the impact of a single 50-mg dose of sildenafil on the sleep of patients with severe obstructive sleep apnea. METHODS: Fourteen middle-aged men with severe obstructive sleep apnea were consecutively selected for this double-blind, placebo-controlled, crossover study. Exclusion criteria were obesity, cardiovascular and/or respiratory disease, and conditions that interfere with sleep. All-night polysomnography was preceded by a single 50-mg dose of sildenafil or matching placebo randomly administered at bedtime, after a washout period of 1 week. RESULTS: In comparison to placebo, a single 50-mg dose of sildenafil significantly increased the percentage of total sleep time with an arterial oxygen saturation of less than 90% (mean +/- SD, 14.2% +/- 9.1% vs 8.5% +/- 3.2%, P < .01), without a difference in the nadir of oxygen desaturation. The mean arterial oxygen saturation also decreased (92.1% +/- 1.91% vs 93.8% +/- 1.3%, P = .02), and the desaturation index increased (30.3 +/- 18.1 events per hour vs 18.5 +/- 14.6 events per hour, P < .001). There was an increase in apnea-hypopnea index (42.4 +/- 25.5 events per hour vs 34.6 +/- 24.1 events per hour, P = .01), involving mostly obstructive events. CONCLUSION: In patients with severe obstructive sleep apnea, a single 50-mg dose of sildenafil at bedtime worsens respiratory and desaturation events.

Published 19 September 2006 in Arch Intern Med, 166(16): 1763-7.
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