SEATTLE, WA—For about one-third of patients treated with zolpidem, only partial improvement is observed, researchers reported at SLEEP 2015.

Although zolpidem is commonly prescribed for chronic insomnia, “reports of mid- to long-term trials, focusing on effectiveness measured both objectively and subjectively, are scarce,” said Laura S. Castro, MSc, from the Department of Psychobiology, Universidade Federal de São Paulo, São Paulo, Brazil.

To evaluate the effectiveness and safety of sublingual zolpidem 5mg given at bedtime and as needed following middle-of-the-night awakenings compared to oral 10mg, Dr. Castro and colleagues conducted a three-month, randomized, double-dummy study that enrolled 67 adults with difficulty initiating and resuming sleep.

Group 1 (n=34) received sublingual zolpidem 5mg and Group 2 (n=33), oral zolpidem 10mg. Each group received three bottles of medication; two were used at bedtime (one with sublingual and the other with oral tablets, active or placebo) and the third bottle, with sublingual tablets, active or placebo, as rescue medication.

“Patients were instructed to take no more than one rescue tablet per night, allowing at least four additional hours of time in bed,” Castro reported.

Mean age of the patients was 50 years and 79% were women. Mean BMI was 26kg/m2. A medical evaluation, sleep diaries, and scales were assessed at baseline and each follow-up visit, and the Psychomotor Vigilance Test and polysomnography were performed at randomization and Week 13.

A total of 152 events were collected by clinicians, of which 38% were rated as unrelated to study medication. Headache, sleepiness, and dizziness were most likely associated adverse events, then gastrointestinal symptoms, and agitation/irritability.

Among the patients analyzed, 55% achieved sustained global clinical improvement at Week 13. Patients taking oral zolpidem 10mg had a greater incidence of symptom recurrence after Week 6, as well as a 1.7 relative risk for treatment failure. Moreover, factors such as “men, divorced, widowed, lower sleep quality baseline scores, and history of musculoskeletal symptoms also associated with treatment failure,” Castro added. These predisposing factors “could possibly be addressed by tailoring dosage,” she concluded.