Clinical efficacy and safety of low-dose doxepin in Chinese patients with generalized anxiety disorder: A before–after study

Clinical and animal studies have reported that low-dose doxepin may have positive effects on generalized anxiety disorder (GAD); however, its effectiveness and clinical safety are less well understood. This study is a before-after study and aims to investigate the effectiveness and side effects of low-dose doxepin by evaluating Hamilton Anxiety Scale (HAMA) scores, hormones, blood glucose, serum lipids, body weight, and body mass index (BMI) in patients with GAD. Forty-nine patients (20 males and 29 females) with GAD were randomly assigned to receive low-dose doxepin (6.25 mg–12.5 mg per day) for 12 weeks between February 2015 and March 2016. HAMA scores, fasting blood glucose (FBG) body weight, BMI, and some serum biochemical indexes, such as adrenocorticotropic hormone (ACTH), free triiodothyronine (FT3), total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDLC), and FBG, were assessed during pretreatment and post-treatment. Mean scores of HAMA decreased from 19.50 ± 1.22 to 8.50 ± 3.61 after low-dose doxepin treatment (P < .01). The serum levels of ACTH (4.33 ± 2.14 vs 6.12 ± 3.02 pmol/L), FT3 (4.78 ± 0.51 vs 5.15 ± 0.52 pg/mL), TC (4.55 ± 1.01 vs 5.93 ± 1.66 mmol/L), TG (1.69 ± 1.51 vs 3.39 ± 2.86 mmol/L), and LDLC (2.43 ± 0.88 vs 3.76 ± 1.25 mmol/L), and FBG (5.06 ± 0.43 vs 5.78 ± 0.81 mmol/L) were higher than that pretreatment with a significant difference (P < .01). Bodyweight (62.00 ± 7.45 vs 64.00 ± 6.44 kg, P = .23) and BMI (23.70 ± 2.35 vs 24.48 ± 2.11 kg/m(2), P = .14) had no difference after treatment. These results suggest that low-dose doxepin has beneficial clinical efficacy and safety. Low-dose doxepin can ameliorate anxiety in GAD patients and has some effects on neuroendocrine systems and the metabolic activity of serum glucose and lipid.