Mirtazapine, an antidepressant

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and dosage and administration of mirtazapine are reviewed. Mirtazapine is a new anti-depressant that blocks presynaptic alpha 2-adrenergic receptors and postsynaptic serotonin type 2 and type 3 receptors. Mirtazapine has FDA-approved labeling for treatment of depression. Limited data suggest it may also have beneficial anxiolytic and sedative effects. The drug is rapidly and completely absorbed after oral administration. It is biotransformed by hepatic demethylation and is suitable for once-daily doses. In several clinical trials, patients receiving mirtazapine showed significantly greater improvement as measured by scores on the Hamilton Rating Scale for Depression (HAM-D) compared with patients receiving placebo. Mirtazapine has been shown to be equally efficacious as amitriptyline, clomipramine, and doxepin as assessed by scores on the HAM-D or other depression rating scales. Mirtazapine is well tolerated. The most commonly reported adverse effects associated with mirtazapine are somnolence, increased appetite, weight gain, and dizziness. Few drug-drug interactions have been reported. The recommended starting dosage is 15 mg/day administered in a single dose at bedtime. Mirtazapine seems to be an effective, well-tolerated antidepressant and may be effective for treating comorbid anxiety disorders.