Mirtazapine + Benzodiazepines - Drug Interactions

The sedative effects of mirtazapine may be increased by benzodiazepines

Clinical evidence,mechanism, importance and management

A single-dose study in 12 healthy subjects found that pharmacokinetics of mirtazapine and diazepam were not affected by concurrent use, but diazepam further impaired action of mirtazapine on objectively measured skill performance; combined actions were mostly additive (See reference number 1). The impairment of psychomotor performance and learning caused by diazepam is increased by mirtazapine and therefore manufacturers warn that sedative effects of benzodiazepines in general may be potentiated by concurrent use with mirtazapine (See reference number 2,3).

Mattila M,Mattila MJ, Vrijmoed-de Vries M, Kuitunen T. Actions and interactions of psychotropic drugs on human performance and mood: single doses of ORG 3770, amitriptyline anddiazepam. Pharmacol Toxicol (1989) 65, 81–8.

Zispin (Mirtazapine). Organon Laboratories Ltd. UK Summary of product characteristics,September 2005.

Remeron (Mirtazapine). Organon USA Inc. US Prescribing information,June 2005.