Mirtazapine

Mirtazapine, sold under the brand name Remeron among others, is an atypical tetracyclic antidepressant, and as such is used primarily to treat depression.^[10][11] Its effects may take up to four weeks but can also manifest as early as one to two weeks.^[11][12] It is often used in cases of depression complicated by anxiety or insomnia.^[10][13] The effectiveness of mirtazapine is comparable to other commonly prescribed antidepressants.^[14] It is taken by mouth.^[11]

Common side effects include sleepiness, dizziness, increased appetite, and weight gain.^[11] Serious side effects may include mania, low white blood cell count, and increased suicide among children.^[11] Withdrawal symptoms may occur with stopping.^[15] It is not recommended together with a monoamine oxidase inhibitor,^[11] although evidence supporting the danger of this combination has been challenged.^[16] It is unclear if use during pregnancy is safe.^[11] How it works is not clear, but it may involve blocking certain adrenergic and serotonin receptors.^[10][11] Chemically, it is a tetracyclic antidepressant,^[11] and is closely related to mianserin. It also has strong antihistaminergic effects.^[10][11]

Mirtazapine came into medical use in the United States in 1996.^[11] The patent expired in 2004, and generic versions are available.^[11][17] In 2023, it was the 99th most commonly prescribed medication in the United States, with more than 6 million prescriptions.^[18][19]