Effects of protriptyline on snoring characteristics.

We evaluated the effects of protriptyline on snoring characteristics in 14 nonapneic snorers (age range, 23 to 54 years; body mass index, 27.4 +/- 0.9 kg/m2, mean +/- SEM). The study design was a double-blind placebo-controlled crossover trial. Patients were evaluated during a polysomnographic study after each 2 weeks of treatment. Breathing sounds were recorded with two microphones symmetrically placed on each side of the bed, the signal being preamplified, equalized, and analyzed by using a real time analyzer. A snoring event was defined as a breathing sound with a sound pressure level (SPL) greater than 60 dB SPL. The snoring index (number/sleep hour) and the sound intensity of each event were automatically determined. Mild side effects were observed in ten subjects, but no subject interrupted the study because of them. The REM sleep time decreased with protriptyline with a parallel increase in stages 1 to 2. There was no difference in body position during sleep between the placebo and protriptyline trials. The snoring index decreased from 335 +/- 40 with placebo to 238 +/- 41 with protriptyline (p < 0.05) with important individual differences. Among the different sleep stages, the highest values of the snoring index were observed in slow-wave sleep with placebo. The snoring index decreased in each sleep stage with protriptyline, the highest decrease occurring in slow-wave sleep. The percentage of total sleep time (TST) spent above 60 dB SPL was significantly lower with protriptyline (6.1 +/- 1.2 percent TST) than with placebo (8.6 +/- 1.2 percent TST). Changes in snoring characteristics were not correlated with snoring severity, the drug blood level, the body mass index, or the drug-induced modifications in sleep architecture. We conclude that protriptyline can improve both snoring frequency and loudness in some nonapneic snorers, and that this improvement occurs mostly in the sleep stages where snoring is worst.