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Chronic dosing with mirtazapine does not produce sedation in rats

Alberto Salazar-Juárez1, Susana Barbosa-Méndez1, Paola Merino-Reyes1

  • 1Laboratorio de Neurobiología Molecular y Neuroquímica de Adicciones, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico.

Revista Brasileira De Psiquiatria (Sao Paulo, Brazil : 1999)
|March 30, 2017
PubMed
Abstract

Insights

Mirtazapine (MIR) causes temporary sedation in rats, with higher doses (30 mg/kg) showing effects only in early treatment. This suggests MIR is well-tolerated for depression therapy.

Area of Science:

  • Pharmacology
  • Neuroscience
  • Behavioral Science

Background:

  • Sedation is a common side effect of depression pharmacotherapies, impacting patient compliance.
  • Mirtazapine (MIR), an atypical antidepressant, is known to cause sedation, particularly in short-term use.
  • Human studies indicate MIR-induced sedation may be transient with higher, repeated doses.

Purpose of the Study:

  • To investigate the acute and chronic effects of various mirtazapine doses on sedation in a rat model.
  • To determine dose-dependent sedative effects of mirtazapine.
  • To assess the duration of mirtazapine-induced sedation.

Main Methods:

  • Behavioral assessments including rotarod, spontaneous locomotor activity, and fixed-bar tests were employed.
  • Rats were administered different doses of mirtazapine.
  • Sedation was evaluated behaviorally.

Main Results:

  • A 15 mg/kg dose of mirtazapine induced sedative effects lasting up to 60 minutes.
  • Doses of 30 mg/kg or higher produced rapid sedation, primarily within the initial days of administration.
  • Sedative effects diminished over time with repeated administration.

Conclusions:

  • Mirtazapine doses of 30 mg/kg and above appear to cause temporary sedative effects in rats.
  • The 30 mg/kg dose of mirtazapine is suggested to be safe and well-tolerated, with transient sedation.
  • These findings support the transient nature of mirtazapine-induced sedation, especially at higher doses.

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