Remeron (Mirtazapine) Antidepressant Information

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Remeron (mirtazapine) is an antidepressant that is chemically unrelated to other antidepressants, which classifies it as an atypical antidepressant.

How Remeron Works

Remeron operates by stimulating production of serotonin and norepinephrine, two brain hormones related to depression. At the same time, it blocks certain receptors associated with side effects that are problematic with some other types of antidepressants, including lowered sex drive, nausea, nervousness, headache, insomnia, and diarrhea.

Remeron is available in tablet form in dosages of 15, 30 and 45 milligrams. It's also available in the same dosages as Remeron SolTabs®, an oral medication that disintegrates on the tongue in a matter of a few seconds. It is recommended that patients start with the lowest dosage.

Remeron Major Precautions and Warnings

Like all other antidepressants, Remeron carries a black box warning relating to the increased risk of suicide and suicidal behavior in children and teenagers. Unlike most other antidepressants, Remeron has a slight risk of causing agranulocytosis, a condition in which the white blood cell count is lowered and the body has difficulty fighting off infections.

More than half the patients who took this antidepressant in the Remeron clinical trials experienced sleepiness, so it's recommended that Remeron be taken at bedtime. Because of the sedating effect, Remeron may also affect your thinking, judgment and motor skills.

This means driving, using machinery and doing other tasks that you need to be alert for are not recommended until you know how it affects you.

Alcoholic beverages can worsen the sedation and dizziness some people experience, so you are advised not to drink alcohol while on this medication. You are also advised to avoid benzodiazepines, which are sometimes prescribed for anxiety and insomnia, because they can also increase these effects.

Gender and Age Variables With Mirtazapine

The mean half-life of mirtazapine is significantly higher for females than males: 37 hours in females and 26 hours in males. This means that it takes an average of 37 hours for half the dose to be eliminated from the body for women and only 26 hours in male. By contrast, in elderly patients, the time for Remeron to clear the system is increased by 40% in males and just 10% in females.

Kidney and Liver Function

In patients with impaired kidney (renal) or liver (hepatic) function, it takes longer for Remeron to be cleared out of the body, so if you have either of these conditions, your dosage should be adjusted down accordingly.

Weight Gain With Mirtazapine

In controlled trials, increased appetite was experienced by 17% of patients, and 7.5% of patients reported gaining at least 7% of their body weight. Anecdotal evidence suggests that significantly greater weight gain is possible.

Mirtazapine for Treatment-Resistant Depression

In spite of the warnings about Remeron, patients who have not had success with more traditional antidepressants such as selective serotonin reuptake inhibitors (SSRIs) and tricyclics may want to give Remeron a try since it works differently from the others.

Common Side Effects of Remeron

These common side effects may go away in time, but if they don't or they are bothersome, be sure to let your doctor know. They include:

  • Dry mouth
  • Weight gain
  • Dizziness
  • Drowsiness
  • Constipation
  • Appetite increase

Sources: (1997). Additional Antidepressants for Depression. Retrieved 9/9/06. [no longer online]. (2006). Prescribing Information for Remeron SolTabs. Retrieved 9/9/06 from (PDF).

"Mirtazapine." Mayo Clinic (2015).

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