Long-term follow-up on restless legs syndrome patients treated with opioids.

The medical records of 493 patients with restless legs syndrome (RLS) from three major centers were studied to determine the number and outcome of patients who had been treated with opioids as a monotherapy. At one time or another 113 patients (51 men, 62 women; age range, 37-88 years) had been on opioid therapy either alone (36 patients) or with opioids added secondarily to other medications used to treat RLS (77 patients). Twenty-three of the 36 opioid monotherapy patients had failed dopaminergic and other therapeutic agents prior to the initiation of opioid monotherapy. Twenty of the 36 opioid monotherapy patients continue on monotherapy for an average of 5 years 11 months (range, 1-23 years), despite their knowledge of the availability of other therapies. Of the 16 patients who discontinued opioids as a sole therapy, the medication was discontinued in only one case because of problems related to addiction and tolerance. Polysomnography on seven patients performed after an average of 7 years 1 month of opioid monotherapy (range, 1-15 years) showed a tendency toward an improvement in all leg parameters and associated arousals (decrease in PLMS index, PLMS arousal index, and PLM while awake index) as well as all sleep parameters (increase in stages 3 and 4 and REM sleep, total sleep time, sleep efficiency, and decrease in sleep latency). Two of these seven patients developed sleep apnea and a third patient had worsening of preexisting apnea. Opioids seem to have long-term effectiveness in the treatment of RLS and PLMS, but patients on long-term opioid therapy should be clinically or polysomnographically monitored periodically for the development of sleep apnea.