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Neuropathic pain is a chronic debilitating condition caused by injury or disease of the nerves of the somatosensory system. Although several therapeutic approaches are recommended, none has emerged as an optimal treatment leaving a need for developing more effective therapies. Given the small number of approved drugs and their limited clinical efficacy, combining drugs with different mechanisms of action is frequently used to yield greater efficacy. We demonstrate that the combination of trazodone, a multifunctional drug for the treatment of major depressive disorders, and gabapentin, a GABA analogue approved for neuropathic pain relief, results in a synergistic antinociceptive effect in the mice writhing test. To explore the potential relevance of this finding in chronic neuropathic pain, pharmacodynamic interactions between low doses of trazodone (0.3 mg/kg) and gabapentin (3 mg/kg) were evaluated in the chronic constriction injury (CCI) rat model, measuring the effects of the two drugs both on evoked and spontaneous nociception and on general well being components. Two innate behaviors, burrowing and nest building, were used to assess these aspects. Besides exerting a significant antinociceptive effect on hyperalgesia and on spontaneous pain, combined inactive doses of trazodone and gabapentin restored in CCI rats innate behaviors that are strongly reduced or even abolished during persistent nociception, suggesting that the combination may have an impact also on pain components different from somatosensory perception. Our results support the development of a trazodone and gabapentin low doses combination product for optimal multimodal analgesia treatment., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: BG, AdM, AA, LP, LD, CM, FPDG and ST are employees of Angelini S.p.A. BG and LD are inventors in patent WO2017067870A1. This does not alter our adherence to PLOS ONE policies on sharing data and materials following signature of an appropriate Material Transfer Agreement.

This double-blind, randomized study evaluated the efficacy and safety of trazodone OAD (once-a-day) in comparison with venlafaxine XR (extended-release) in 324 patients (166 trazodone and 158 venlafaxine) with major depressive disorder (MDD). The primary efficacy endpoint was the mean change from baseline in the 17-item Hamilton Depression Rating Scale (HAM-D) at week 8. Both treatments were effective in reducing the HAM-D-17 total score at week 8 vs. baseline (intent-to-treat: trazodone -12.9, venlafaxine -14.7; per protocol: trazodone -15.4, venlafaxine -16.4). Patients in the venlafaxine group achieved better results after 8 weeks, whereas the trazodone group achieved a statistically significant reduction in HAM-D-17 following only 7 days of treatment. The most frequent adverse events (AEs) were dizziness and somnolence in the trazodone group, and nausea and headache in the venlafaxine group. Most AEs were mild-to-moderate in severity. This study confirmed that both venlafaxine XR and trazodone OAD may represent a valid treatment option for patients with MDD.

There is a paucity of clinical trials for the treatment of pediatric insomnia. This study was designed to predict the doses of trazodone to guide dosing in a clinical trial for pediatric insomnia using physiologically-based pharmacokinetic (PBPK) modeling. Data on the pharmacokinetics of trazodone in children are currently lacking. The interaction potential between trazodone and atomoxetine was also predicted. Doses predicted in the following age groups, with exposures corresponding to adult dosages of 30, 75, and 150 mg once a day (q.d.), respectively, were: (i) 2- to 6-year-old group, doses of 0.35, 0.8, and 1.6 mg/kg q.d.; (ii) >6- to 12-year-old group, doses of 0.4, 1.0, and 1.9 mg/kg q.d.; (iii) >12- to 17-year-old group, doses of 0.4, 1.1, and 2.1 mg/kg q.d. An interaction between trazodone and atomoxetine was predicted to be unlikely. Clinical trials based on the aforementioned predicted dosing are currently in progress, and pharmacokinetic data obtained will enable further refinement of the PBPK models., (© 2019 ANGELINI S.p.A. CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals, Inc. on behalf of the American Society for Clinical Pharmacology and Therapeutics.)

Aim: Trazodone (TZD) is used for the treatment of depression in adults and, off-label, as a sleep medication in adult and pediatric populations. The off-label use is well documented, however further clinical studies are needed to confirm its efficacy and safety for the treatment of sleep disorders. In this scenario, we developed a bioanalytical method to quantify low TZD concentrations in samples collected by capillary microsampling (CMS) to support dose finding, Good Laboratory Practice juvenile rat toxicokinetic and upcoming pediatric studies., Methodology: A method using only 8 μl of plasma was developed and successfully used for analyzing CMS samples from juvenile rats throughout toxicokinetic study., Conclusion: By harmoniously maximizing each analytical step, we achieved a sensitive method to quantify TZD in CMS samples.