Efficacy and safety of doxepin 6 mg in a four-week outpatient trial of elderly adults with chronic primary insomnia.

INTRODUCTION: The efficacy and safety of doxepin (DXP), a histamine H(1) receptor antagonist, was evaluated in elderly adults with sleep maintenance insomnia. METHODS: This was a randomized, double-blind, placebo-controlled outpatient trial. Elderly adults meeting DSM-IV-TR criteria for primary insomnia were randomized to four weeks of nightly treatment with either DXP 6 mg (N=130) or placebo (PBO; N=124). Efficacy was assessed using patient self-report instruments and clinician ratings. Patient-reported endpoints included subjective total sleep time (sTST), subjective wake after sleep onset (sWASO), latency to sleep onset (LSO), sleep quality, and a Patient Global Impression scale (PGI). The primary endpoint was sTST at week 1. RESULTS: DXP 6 mg produced significantly more sTST and less sWASO at week 1 (both p-values <0.0001) than PBO. These significant improvements versus placebo were maintained at weeks 2-4 (all p-values <0.05). There were no significant differences in LSO for DXP 6 mg versus PBO. DXP 6 mg significantly improved sleep quality (weeks 1, 3, and 4, p<0.05) and several outcome-related parameters, including several items on the PGI, the severity and improvement items of the Clinician Global Impression scale (CGI; weeks 1 and 2) and the Insomnia Severity Index (ISI; weeks 1-4), all versus PBO. There were no reports of anticholinergic effects (e.g., dry mouth) or memory impairment. The safety profile of DXP 6 mg was comparable to that of PBO. CONCLUSIONS: In elderly adults with insomnia, DXP 6 mg produced significant improvements in sleep maintenance, sleep duration, and sleep quality endpoints that were sustained throughout the trial. These data suggest that DXP 6 mg is effective for treating sleep maintenance insomnia and is well-tolerated in elderly adults with chronic primary insomnia.

Efficacy and safety of doxepin 3 and 6 mg in a 35-day sleep laboratory trial in adults with chronic primary insomnia.

STUDY OBJECTIVES: To evaluate the efficacy and safety of doxepin (DXP) 3 mg and 6 mg in adults diagnosed with primary insomnia. DESIGN AND METHODS: The study was a randomized, double-blind, parallel-group, placebo-controlled trial. Patients meeting DSM-IV-TR criteria for primary insomnia were randomized to 35 days of nightly treatment with DXP 3 mg (n=75), DXP 6 mg (n=73), or placebo (PBO; n=73), followed by 2 nights of single-blind PBO to evaluate discontinuation (DC) effects. Efficacy was assessed using polysomnography (PSG) and patient reports. Efficacy data were examined for Night (N) 1, N15, and N29. Safety assessments were conducted throughout the study. RESULTS: Compared with PBO, DXP 3 and 6 mg significantly improved wake time after sleep onset (WASO) on N1 (3 mg and 6 mg; P<0.0001), N15 (3 mg P=0.0025; 6 mg P=0.0009), and N29 (3 mg P=0.0248; 6 mg P=0.0009), latency to persistent sleep (LPS) on N1 (3 mg P=0.0047; 6 mg P=0.0007), and total sleep time (TST) on N1 (3 mg and 6 mg P<0.0001), N15 (6 mg P=0.0035), and N29 (3 mg P=0.0261; 6 mg P<0.0001). In terms of early morning awakenings, DXP 3 and 6 mg demonstrated significant improvements in SE in the final quarter of the night on N1, N15, and N29, with the exception of 3 mg on N29 (P=0.0691). Rates of discontinuation were low, and the safety profiles were comparable across the 3 treatment groups. There were no significant next-day residual effects, and there were no spontaneous reports of memory impairment, complex sleep behaviors, anticholinergic effects, weight gain, or increased appetite. Additionally, there was no evidence of rebound insomnia after DXP discontinuation. CONCLUSIONS: Five weeks of nightly administration of DXP 3 mg and 6 mg to adults with chronic primary insomnia resulted in significant and sustained improvements in sleep maintenance and early morning awakenings (with the exception of SE in the final quarter of the night on N29 for 3 mg [P=0.0691]). These sleep improvements were not accompanied by next-day residual effects or followed by rebound insomnia or withdrawal effects upon discontinuation. These findings confirm the unique profile of sleep maintenance efficacy and safety of DXP observed in prior studies.

A placebo- and active-controlled assessment of 6- and 50-mg oral doxepin on cardiac repolarization in healthy volunteers: a thorough QT evaluation.

BACKGROUND: Doxepin tablets have recently been approved in the United States in doses of 3 and 6 mg for the treatment of insomnia characterized by difficulty with sleep maintenance. OBJECTIVE: Because no previous thorough QT evaluation of doxepin has been conducted, the primary objective of this study was to assess the highest recommended dose (6 mg) and a supratherapeutic amount (50 mg) of doxepin on cardiac repolarization under steady-state conditions in healthy adult subjects. METHODS: Male and female volunteers aged 18 to 45 years were randomized to receive double-blind doxepin or placebo for 7 days, or 6 days of double-blind placebo before one open-label administration of 400-mg moxifloxacin on day 7. Holter electrocardiograms were collected at baseline and on day 7 for up to 23.5 hours after dosing; the results were read at a central facility. The primary outcome measure was the time-matched change from baseline in individually corrected QT (QTcI) intervals. Additional outcome measures were used to evaluate outlying QTc values and the relationship of QTcI to plasma concentrations of doxepin and its primary demethylated metabolite, nordoxepin. RESULTS: A total of 206 healthy subjects (108 women, 98 men) were randomized to a study group; 192 subjects (93.2%) received all scheduled administrations of study drug, and 190 subjects (92.2%) completed the study. The study population was 47.6% male and 52.4% female, and the mean age was 30.3 years. Neither amount of administered doxepin increased QTcI, nor did the upper bound of the 95% CIs for the point estimates exceed 10 milliseconds at any time point. The results for moxifloxacin met the assay sensitivity criteria for a positive control. The predicted placebo-corrected change in QTcI at the mean doxepin C(max) values for both administered amounts (6 mg: -0.88 millisecond [upper CI: 0.37 millisecond]; 50 mg, 2.38 milliseconds [upper CI: 4.00 milliseconds]) did not suggest an effect on cardiac repolarization, and no doxepin-treated subject met specific criteria for outlying QTc values. CONCLUSION: This thorough QT study revealed no effects of doxepin on QTcI up to 50 mg, suggesting that doxepin therapy for insomnia is unlikely to increase QTc intervals.

Efficacy and Safety of Doxepin 1 mg and 3 mg in a 12-week Sleep Laboratory and Outpatient Trial of Elderly Subjects with Chronic Primary Insomnia.

STUDY OBJECTIVES: to evaluate the efficacy and safety of doxepin 1 mg and 3 mg in elderly subjects with chronic primary insomnia. DESIGN AND METHODS: the study was a randomized, double-blind, parallel-group, placebo-controlled trial. Subjects meeting DSM-IV-TR criteria for primary insomnia were randomized to 12 weeks of nightly treatment with doxepin (DXP) 1 mg (n = 77) or 3 mg (n = 82), or placebo (PBO; n = 81). Efficacy was assessed using polysomnography (PSG), patient reports, and clinician ratings. Objective efficacy data are reported for Nights (N) 1, 29, and 85; subjective efficacy data during Weeks 1, 4, and 12; and Clinical Global Impression (CGI) scale and Patient Global Impression (PGI) scale data after Weeks 2, 4, and 12 of treatment. Safety assessments were conducted throughout the study. RESULTS: DXP 3 mg led to significant improvement versus PBO on N1 in wake time after sleep onset (WASO; P < 0.0001; primary endpoint), total sleep time (TST; P < 0.0001), overall sleep efficiency (SE; P < 0.0001), SE in the last quarter of the night (P < 0.0001), and SE in Hour 8 (P < 0.0001). These improvements were sustained at N85 for all variables, with significance maintained for WASO, TST, overall SE, and SE in the last quarter of the night. DXP 3 mg significantly improved patient-reported latency to sleep onset (Weeks 1, 4, and 12), subjective TST (Weeks 1, 4, and 12), and sleep quality (Weeks 1, 4, and 12). Several global outcome-related variables were significantly improved, including the severity and improvement items of the CGI (Weeks 2, 4, and 12), and all 5 items of the PGI (Week 12; 4 items after Weeks 2 and 4). Significant improvements were observed for DXP 1 mg for several measures including WASO, TST, overall SE, and SE in the last quarter of the night at several time points. Rates of discontinuation were low, and the safety profiles were comparable across the 3 treatment groups. There were no significant next-day residual effects; additionally, there were no reports of memory impairment, complex sleep behaviors, anticholinergic effects, weight gain, or increased appetite. CONCLUSIONS: DXP 1 mg and 3 mg administered nightly to elderly chronic insomnia patients for 12 weeks resulted in significant and sustained improvements in most endpoints. These improvements were not accompanied by evidence of next-day residual sedation or other significant adverse effects. DXP also demonstrated improvements in both patient- and physician-based ratings of global insomnia outcome. The efficacy of DXP at the doses used in this study is noteworthy with respect to sleep maintenance and early morning awakenings given that these are the primary sleep complaints of the elderly. This study, the longest placebo-controlled, double-blind, polysomnographic trial of nightly pharmacotherapy for insomnia in the elderly, provides the best evidence to date of the sustained efficacy and safety of an insomnia medication in older adults.

Efficacy and safety of doxepin 6 mg in a model of transient insomnia.

INTRODUCTION: The efficacy and safety of doxepin (DXP) 6mg tablets were evaluated in healthy adults in a model of transient insomnia. METHODS: This was a randomized, double-blind, parallel-group, placebo-controlled study in healthy adults using a model of transient insomnia. A first-night effect combined with a 3-h phase advance was implemented to induce transient insomnia in healthy adults. Subjects received a single night time dose of placebo (PBO; N=282) or DXP 6mg (N=283) in a sleep laboratory. Efficacy was evaluated objectively (polysomnography; PSG) and subjectively (morning questionnaire). Consistent with the model utilized, the primary endpoint was latency to persistent sleep (LPS); secondary PSG endpoints included wake after sleep onset (WASO; key secondary endpoint), total sleep time (TST), wake time after sleep (WTAS) and sleep efficiency (SE; overall, by quarter of the night and hourly); secondary subjective endpoints included latency to sleep onset (LSO), subjective WASO (sWASO), subjective TST (sTST) and sleep quality. RESULTS: DXP 6mg demonstrated statistically significant improvements in LPS (13min decrease versus PBO; p<0.0001), WASO (39min less than PBO; p<0.0001), TST (51min more than PBO; p<0.0001), WTAS (p<0.0001), overall SE (p<0.0001), SE in each quarter of the night (p<0.0001) and SE in each of the 8h (p⩽0.0003), all versus PBO. Additionally, DXP 6mg significantly improved subjective variables including LSO (p<0.0001), sWASO (p=0.0063), sTST (p<0.0001), and sleep quality (p=0.0004), versus PBO. There was no consistent evidence of next-day residual sedation and also minor sleep stages alterations. The incidence of adverse events was comparable to placebo. CONCLUSIONS: In this model of transient insomnia, DXP 6mg demonstrated significant improvements in sleep onset, sleep maintenance, sleep duration and sleep quality, and also appeared to reduce early morning awakenings. These data suggest that DXP 6mg may be effective and well tolerated in adults experiencing transient insomnia.

Efficacy and safety of doxepin 1 mg, 3 mg, and 6 mg in elderly patients with primary insomnia: a randomized, double-blind, placebo-controlled crossover study.

OBJECTIVES: Evaluate efficacy and safety of the histamine-H1 antagonist doxepin at doses of 1 mg, 3 mg, and 6 mg in elderly adults with primary insomnia. DESIGN: A randomized, double-blind, placebo-controlled, crossover design was used in this population of elderly adults with primary insomnia (DSM-IV). Each treatment period consisted of 2 polysomnographic (PSG) assessment nights with a 5- or 12-day drug-free interval between periods. The study was conducted from September 2004 to January 2005. SETTING: Sleep laboratories in 11 sleep centers in the United States. PARTICIPANTS: Elderly adults with primary insomnia. INTERVENTION: Doxepin 1 mg, 3 mg, and 6 mg. MEASUREMENTS: Efficacy was assessed using PSG and patient-reported measures. RESULTS: Seventy-six patients were randomly assigned. All 3 doxepin doses produced dose-related significant improvements in PSG-determined wake time during sleep (p < .0001), wake time after sleep onset (p < .0001), total sleep time (p < .0001), and overall sleep efficiency (p < .0001) versus placebo. At the 3-mg and 6-mg doses, sleep efficiency was significantly improved during all thirds of the night (p < .05). There was a dose-related decrease in patient-reported sleep latency, with the 6-mg dose achieving statistical significance in latency to sleep onset (p = .0181). The pattern of the remaining subjective efficacy results was consistent with PSG. All 3 doxepin doses had side effect profiles comparable to placebo, with no spontaneously reported anticholinergic effects, no memory impairment, and no significant next-day residual effects. CONCLUSIONS: In this 2-night study of elderly adults with primary insomnia, doxepin doses of 1 mg, 3 mg, and 6 mg were well tolerated and produced significant improvement in objective and subjective sleep maintenance and duration endpoints that persisted into the final hour of the night. Positive effects on patient-reported sleep onset were observed at the highest dose. All 3 doxepin doses had a safety profile comparable to placebo. These data demonstrate that doxepin was efficacious in improving sleep in elderly adults.

Efficacy and safety of doxepin 1 mg, 3 mg, and 6 mg in adults with primary insomnia.

STUDY OBJECTIVES: To evaluate the efficacy and safety of doxepin 1, 3, and 6 mg in insomnia patients. DESIGN: Adults (18-64 y) with chronic primary insomnia (DSM-IV) were randomly assigned to one of four sequences of 1 mg, 3 mg, and 6 mg of doxepin, and placebo in a crossover study. Treatment periods consisted of 2 polysomnographic assessment nights with a 5-day or 12-day drug-free interval between periods. Efficacy was assessed using polysomnography (PSG) and patient-reported measures. Safety analyses included measures of residual sedation and adverse events. MEASUREMENTS AND RESULTS: Sixty-seven patients were randomized. Wake time during sleep, the a priori defined primary endpoint, was statistically significantly improved at the doxepin 3 mg and 6 mg doses versus placebo. All three doses had statistically significant improvements versus placebo for PSG-defined wake after sleep onset, total sleep time, and overall sleep efficiency (SE). SE in the final third-of-the-night also demonstrated statistically significant improvement at all doses. The doxepin 6 mg dose significantly reduced subjective latency to sleep onset. All three doxepin doses had a safety profile comparable to placebo. There were no statistically significant differences in next-day residual sedation, and sleep architecture was generally clinically preserved. CONCLUSIONS: In adults with primary insomnia, doxepin 1 mg, 3 mg, and 6 mg was well-tolerated and produced improvement in objective and subjective sleep maintenance and duration endpoints that persisted into the final hour of the night. The side-effect profile was comparable to placebo, with no reported anticholinergic effects, no memory impairment, and no significant hangover/next-day residual effects. These data demonstrate that doxepin 1 mg, 3 mg, and 6 mg is efficacious in improving the sleep of patients with chronic primary insomnia.