From the Guidelines
Mirtazapine is associated with several common side effects, including sleep disorders, constipation or diarrhea, anxiety, increased appetite and weight gain, nausea, headache, and fatigue, as reported in the most recent study 1.
Common Side Effects
The most recent study 1 provides a comprehensive overview of the common side effects of mirtazapine, which include:
- Sleep disorders
- Constipation or diarrhea
- Anxiety
- Increased appetite and weight gain
- Nausea
- Headache
- Fatigue These side effects are dose-dependent, with higher doses (up to 45mg) potentially causing more pronounced effects.
Comparison with Other Studies
While an earlier study 2 reported similar side effects, including constipation, diarrhea, dizziness, headache, insomnia, nausea, and somnolence, the most recent study 1 provides more specific information on the side effects of mirtazapine.
Management of Side Effects
It is essential to note that most side effects are more pronounced during the first few weeks of treatment and often diminish over time as the body adjusts to the medication. If side effects persist or become bothersome, consulting a healthcare provider may help manage these effects while maintaining the antidepressant benefits. Dosage adjustments or timing changes may be necessary to minimize side effects.
From the FDA Drug Label
Mirtazapine tablets may cause serious side effects, including: • Low white blood cell count. • Serotonin syndrome • Eye problems (angle-closure glaucoma). • Heart rhythm problems. • Severe skin reaction • Increased appetite and weight gain. • Sleepiness. • Mania or hypomania (manic episodes) in people who have a history of bipolar disorder. • Seizures (convulsions). • Increased fat levels (cholesterol and triglycerides) in your blood • Low sodium levels in your blood (hyponatremia). • Changes in liver function tests. • Discontinuation syndrome. The most common side effects of mirtazapine tablets include: • sleepiness • increased appetite • weight gain • dizziness
The side effects of mirtazapine include low white blood cell count, serotonin syndrome, eye problems, heart rhythm problems, severe skin reaction, increased appetite and weight gain, sleepiness, mania or hypomania, seizures, increased fat levels, low sodium levels, changes in liver function tests, and discontinuation syndrome. The most common side effects are sleepiness, increased appetite, weight gain, and dizziness 3.
From the Research
Side Effects of Mirtazepine
- The study 4 found that mirtazapine increases the risks of somnolence, weight gain, dry mouth, dizziness, and increased appetite.
- The same study 4 also found that mirtazapine might decrease the risk of headaches.
- Another study 5 reported that more participants in the mirtazapine group withdrew from the trial medication, citing mild adverse events (46 vs. 9 participants).
- The study 6 found that the efficacy of mirtazapine increases up to a dose of about 30 mg and then decreases.
- Common side effects of antidepressants, including mirtazapine, may include gastrointestinal disturbances, headache, sedation, insomnia, activation, weight gain, impaired memory, excessive perspiration, paresthesia, and sexual dysfunction 7.
Serious Adverse Events
- The study 4 found insufficient information to determine the effects of mirtazapine on the risks of suicides or suicide attempts and serious adverse events.
- Another study 8 found that the combination of SSRIs with other drugs, such as antidepressants and opioids, can increase the risk of serotonin syndrome, a potentially life-threatening adverse event.
Long-Term Effects
- The study 4 noted that the long-term effects of mirtazapine are unknown, as the included trials assessed outcomes at a maximum of 12 weeks after randomization.
- The study 5 found that the difference in depression symptoms between the mirtazapine group and the placebo group became smaller at subsequent time points (24 weeks and 12 months).