THE CANADIAN JOURNAL OF NEUROLOGICAL SCIENCES Nitrazepam for Periodic Movements in Sleep (Sleep-related Myoclonus)

In a follow-up study (mean, approximately six months), nitrazepam was helpful in suppressing periodic movements in sleep (sleep-related myoclonus) and improving disturbed sleep physiology and daytime symptoms of 13 patients (mean age 53 yr). RESUME: Le nitrazepam dans les mouvements periodiques pendant le sommeil (myoclonies du sommeil) Nous d6montrons, a la suite d'une etude suivie pour au moins 6 mois, que le nitrazepam est utile pour supprimer les mouvements p£riodiques observes pendant le sommeil (myoclonies du sommeil) et pour ameMiorer la physiologie trouble du sommeil et les symptomes diurnes chez 13 patients (age moyen 53 ans). Can. J. Neurol. Sci. 1986; 13:52-54 Sleep-related (nocturnal) myoclonus or periodic movements in sleep (PMS) are periodic, involuntary, stereotyped movements of the lower limbs that typically occur at 20to 40-sec intervals during sleep. PMS has been found in 13.3% of disorders of initiating and maintaining sleep (insomnia) and 6.9% of disorders of excessive daytime somnolence among 6,422 patients investigated by polysomnography. The disorder is found in 18% of the aged ; accompanies certain medical disorders including end stage renal disease, rheumatic pain modulation disorder or "fibrositis syndrome",and restless legs syndromeand may be associated with sleep-related disorders, narcolepsy and cataplexy; and sleep apnea. The etiology of this disorder is unknown. Anecdotal reports have suggested varyingly successful treatment with folic acid, iron supplement, an alpha-receptor blocking agent, and several benzodiazepine medications, e.g., lorazepam,temazepam,and several with clonazepam. Symptomatic effects on those patients with daytime somnolence or insomnia and follow-up studies have not been systematically reported with any of these drugs. In this paper we report on the efficacy of nitrazepam in controlling PMS and sleep-related and daytime symptoms in patients with either chronic insomnia or excessive daytime somnolence. Nitrazepam was selected because it is a benzodiazepine, structurally similar to clonazepam, has an elimination half-life somewhat shorter (15 to 38 hr) than clonazepam (18 to 50 hr), and, like clonazepam, has been shown to be effective in the treatment of myoclonic epilepsy. MATERIALS AND METHOD Thirteen patients who had been investigated with medical and psychiatric examinations for complaints of excessive daytime somnolence (EDS, N = 8) or intractable disorder of initiating and maintaining sleep (DIMS, N = 5) were found by polysomnography to have PMS. The patients (10 males, 3 females, mean age 53.3 yr) had their disorders for a mean of 7.3 years (S.D., 9.8). None of the patients had any other sleeprelated disorder. Within the group, there were a variety of medical disorders: two had essential hypertension; one had a residual mild left-sided stroke; one had partial complex epilepsy controlled by phenytoin; one had leg cramps; three had end stage renal disease successfully treated by continuous ambulatory peritoneal dialysis; two had restless legs syndrome with migraine and "fibrositis syndrome"; one had iron deficiency anemia associated with menorrhagia treated by ferrous sulphate; one had coronary artery disease, chronic low back and lower limb pain; and one had no associated medical or psychiatric disorder. They had not received any hypnotic, tranquilizer or antidepressant medication for at least two weeks prior to the initial, or baseline, sleep study. If indicated, they continued with their antihypertensive, cardiac, or antacid medications. Sleep studies were carried out in a sound-attenuated bedroom over one night. During the previous day, neither alcohol, caffeine substances, nor naps were permitted. Sleep recordings consisted of electroencephalogram (EEG) C3-A2 and C4-A1, From the bieep Disorders Clinic, Department of Psychiatry, Toronto Western Hospital, Toronto Received May 30, 1985. Accepted in revised form November 21, 1985 Reprint requests to: Harvey Moldofsky, M.D., Department of Psychiatry, Toronto Western Hospital, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8