Long-term compliance, safety, and tolerability of sodium oxybate treatment in patients with narcolepsy type 1: A postauthorization, noninterventional surveillance study

Study Objectives: To evaluate adherence to sodium oxybate prescribing information for indication and dosage, patients' compliance with instructions for use, safety/tolerability in routine clinical practice, and abuse potential. Methods: A postauthorization, noninterventional surveillance study (NCT00244465) in patients who were prescribed sodium oxybate according to current practice by sleep disorders specialists. Patients were monitored for ≤18 months. Results: Overall, 749 patients were enrolled; 730 included in the intent-to-treat population (narcolepsy type 1 n = 670, other indications n = 60). We report on patients with narcolepsy type 1 (female 47.9%, mean age 39.4 years); 495/670 (73.9%) completed the study. Median dose: at start of study 4.5 g per night, 6 g per night throughout study, in two equal doses. According to the treatment compliance checklist, 35.5 per cent of patients consumed alcohol, 19.3 per cent took the medication <2 hr after food, and 27.1 per cent did not adhere to recommended time schedule, with few associated treatment-emergent adverse events (TEAEs). Incidences of higher-than-recommended doses, difficulty in preparing doses, and abuse were low. TEAEs were reported by 67.3 per cent, most frequently headache (11.6%) and nasopharyngitis (6.4%). Discontinuation due to TEAEs: 8.8 per cent. Serious TEAEs: 6.4 per cent. There were no reports of respiratory depression. No particular safety concerns were identified in pediatric or elderly patients, or those with underlying sleep apnea. Conclusions: In this large postauthorization safety study of sodium oxybate use, indication and dosage prescribing recommendations were generally followed, and most patients complied with instructions, with deviations around alcohol consumption, eating before dosing and timing. The overall safety profile was consistent with previous observations; incidence of abuse was low.