Mirtazapine Side Effects

Mirtazapine is a medication prescribed to treat major depression. Sold in generic form and under the brand names Remeron, Zispin and Avanza, mirtazapine belongs to the class of drugs called tetracyclic antidepressants. Numerous side effects are possible.

Most Common Effect

• In clinical studies with mirtazapine, the most common side effect was drowsiness, occurring in more than half the participants. The drug is usually taken at bedtime because of this side effect, but drowsiness is still a common reason people stop using mirtazapine.

Other Common Effects

• Other common side effects in the mirtazapine clinical studies included dry mouth, increased appetite, weight gain, high cholesterol and triglyceride levels, constipation, dizziness and weakness.

Less Common Effects

• Between 1 to 5 percent of participants experienced abnormal dreams, abnormal thoughts, confusion, fever and chills, fluid retention, frequent urination, muscle pain or back pain, and shakiness or tremors.

Warning

• As with all other antidepressant medications, the U.S. Food and Drug Administration requires a black box warning on mirtazapine labeling. The warning addresses increased risk of suicidal thoughts and behavior in children and adolescents. Mirtazapine is not approved for treating anyone under age 18.

Drug Interactions

• Mirtazapine can interact with many drugs. These include alcohol, anti-anxiety medications, antihistamines, high blood pressure medicine, monoamine oxidase inhibitors, narcotic medications, tranquilizers and other antidepressants.