esmirtazapine

Esmirtazapine is the (S)-(+)-enantiomer of mirtazapine, a tetracyclic antidepressant developed by Organon and later Merck for the treatment of insomnia and vasomotor symptoms associated with menopause. It acts as an antagonist at histamine H1 receptor and serotonin 5-HT2A receptor, with additional antagonism at α2-adrenergic receptors. Esmirtazapine enhances norepinephrine and serotonin release by blocking presynaptic α2-adrenoceptors, blocks both 5-HT2 and 5-HT3 serotonin receptors, and is a potent H1 receptor antagonist. Its shorter half-life (~10 hours) compared to racemic mirtazapine was intended to reduce next-day sedation risk in insomnia treatment. Clinical trials reached phase III for insomnia and vasomotor symptoms but development was terminated in March 2010 for strategic reasons[1][3][4][7].

Other names

(S)-mirtazapine(+)-mirtazapineesmirtazapine maleate