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What is Remeron?

Remeron (mirtazapine), manufactured by Organon Inc., is a new antidepressant medication that was cleared by the FDA for the treatment of depression in June 1997. Remeron is the first drug in a new class of antidepressants with a unique ability to target specific serotonin receptors. Along with its efficacy in the treatment of moderate to severe depression, Remeron has proven to be effective for treating anxiety, motor retardation, and cognitive and sleep disturbances associated with depression.

How is Remeron different from other antidepressants?

Remeron has a tetracyclic chemical structure that causes it to act differently from other common antidepressants (SSRIs, MAOIs, and tricyclics). While stimulating norepinephrine and serotonin release, Remeron also has the unique ability to block two specific serotonin receptors, thus causing fewer serotonergic side effects (decreased interest in sex, nausea, nervousness, insomnia, and diarrhea). In studies, the use of Remeron, compared with tricyclic antidepressants, also resulted in fewer anticholinergic symptoms (blurred vision, dry mouth, indigestion, and constipation), cardiovascular symptoms, and cognitive disturbances. Additionally, Remeron has a relatively high safety margin in case of overdose and a low tendency to cause seizures. It causes no significant changes in vital signs (heart rate, blood pressure, or body temperature) or ECG.

What are the side effects of Remeron?

Side effects observed in clinical trials were mostly mild and generally have not caused consumers to stop taking Remeron. The most commonly reported drug-related side effects were drowsiness, increased appetite, weight gain, and dizziness. In studies, drowsiness generally appeared during the first week of treatment but decreased in intensity over time, even as dosages increased. Other side effects may also lessen in severity, or go away, with prolonged use of the drug.

In clinical trials, two out of 2,796 consumers treated with Remeron developed agranulocytosis and a third consumer developed severe neutropenia-both potentially dangerous decreases in white blood cell counts that cause extreme vulnerability to infection. These consumers recovered after Remeron was stopped. However, it should be noted that if a consumer develops a sore throat, fever, inflammation of the mouth, or other signs of infection, he or she should discontinue treatment with Remeron under the supervision of a doctor.

How does Remeron interact with other medications?

Use with other antidepressants is not recommended (especially MAOIs), unless closely supervised by the prescribing physician. Use of other drugs that cause drowsiness (antihistamines, prescription painkillers, Valium, Xanax) may increase this effect and impair driving or other motor or coordination skills. Use with central nervous system stimulants (Fastin, Dexedrine, Ritalin) may cause an increase in agitation or even mania, especially in bipolar patients. As with other antidepressants, avoidance of alcohol is best.

Immunocompromised consumers, consumers with HIV, and consumers on steroid therapy should call their physician at the first sign of sore throat, fever, chills, sores in and around the soft tissue of the mouth, or any general flu-like symptoms so that further immune system damage does not occur.

What is the recommended dosage of Remeron?

Remeron is available in both 15 mg (yellow) and 30 mg (red-brown) tablets. The recommended starting dose is 15 mg per day given in a single dose before bedtime, and it can be taken with or without food. It is recommended that one to two weeks pass before making upward dosage adjustments, in small increments. The effective dose range of Remeron is generally 15-45 mg/day. In patients with liver and kidney disease, a smaller dose may be appropriate. As with other antidepressants, it may take several weeks of therapy before improvement is noticeable.

Reviewed by Matthew V. Rudorfer, M.D., assistant chief, Adult and Geriactric Treatment and Preventive Interventions Research Branch, NIMH. February 1998