Mirtazapine

What it is

Mirtazapine is a noradrenergic and specific serotonergic antidepressant. It blocks presynaptic alpha-2 receptors, which increases noradrenaline and serotonin release, and blocks certain serotonin and histamine receptors, which produces sedation rather than the restlessness of other antidepressants. It is used for depression and, largely because of that sedating effect, for sleep problems that accompany it.

A usual adult range, not a national label — the dose and the timing differ by country and by product.

Used for

• Depression
• Insomnia

Approved uses differ by country — some of these may be off-label or unapproved where you live.

What to know while taking it

It is taken at bedtime, with or without food, and sedation is often strongest at the beginning. Increased appetite and weight gain are common and follow directly from the histamine blockade, so total cholesterol is worth checking over time along with ALT as a liver measure. White blood cells are monitored because a rare drop in neutrophils has been described with this drug. As with other antidepressants, stopping abruptly can cause dizziness, nausea and sleep disturbance.

When to see a doctor

See a doctor for fever, sore throat, mouth ulcers or any infection that seems slow to clear, since these can be the first sign of a fall in white cells. Yellowing of the skin or eyes, and rapid or unexplained weight change, also warrant review.

Worth knowing

• Causes drowsiness
• Can change appetite
• Can change body weight
• Do not stop abruptly

Markers to watch

• White blood cells
• ALT
• Total cholesterol