Subjective hypnotic efficacy of Trazodone and Mirtazapine in patients with chronic insomnia: a retrospective, comparative study

OBJECTIVE: To compare the efficacy of two sedating antidepressants, trazodone and mirtazapine, for the treatment of chronic insomnia. DESIGN: Retrospective cross-sectional study. Patients received trazodone or mirtazapine for at least three months at the dosage that was effective in the titration period. MATERIAL AND METHODS: 150 patients with chronic insomnia, referred to the Sleep Disorder Center of Bari, diagnosed as chronic insomniacs according to ICSD-3 diagnostic criteria, with or without dysthymic disorder according to DSM V diagnostic criteria, and treated with trazodone or mirtazapine were retrospectively chart-reviewed. 79 patients satisfying inclusion criteria were enrolled: 33 had been treated with trazodone (12 males and 21 females aged 36 to 77 years, mean age 63.57+10.38 years; 18 with psychophysiological insomnia and 15 with insomnia associated with dysthymic disorder) and 46 with mirtazapine (26 males and 20 females aged 25 to 86 years, mean age 60.04+16.67 years; 25 with psychophysiological insomnia and 21 with insomnia comorbid with dysthymic disorder). The patients were considered responsive to the treatment when they no longer met the criteria for insomnia at the end of the maintenance period. RESULTS: Both drugs were efficacious in more than 60% without any difference in the proportion of responders between the two medication groups (87.87% in the trazodone group versus 86.95% in the mirtazapine group; p=0.26 and regardless of sex, age and possible association of insomnia with depression). The minimum dosages used for both drugs (25 mg for trazodone and 7.5 mg for mirtazapine) corresponded to the highest percentage of responders in the groups treated successfully with either trazodone (37.93%) or mirtazapine (52.5%). For each medication group, subgroup analysis revealed higher statistically significant rates of responders in patients with lower final dosage (25 to 75 mg for trazodone and 7.5 to 15 mg for mirtazapine) than in those with higher final dosage (100 to 150 mg for trazodone and 15 to 30 mg for mirtazapine) (100% versus 42.85%; p<0.001 in the trazodone group and 100% versus 53.84%; p<0.001 in mirtazapine group) Conclusion. On a long term basis trazodone administration appeared as effective and well tolerated as mirtazapine in the treatment of chronic insomnia regardless of its association with dysthymia. Both medications resulted efficacious at very low doses and had a sustained efficacy, likely without problems of tolerance.