Can Mirtazapine Cause Vomiting?
No, mirtazapine does not typically cause vomiting and is actually associated with significantly lower rates of nausea and vomiting compared to other antidepressants, particularly SSRIs. In fact, mirtazapine is increasingly being used therapeutically to treat nausea and vomiting in various clinical settings 1, 2, 3.
Evidence from Guidelines and Comparative Studies
The American College of Physicians guideline on second-generation antidepressants explicitly states that mirtazapine had lower rates of nausea and vomiting compared to other agents like venlafaxine and SSRIs 4. The guideline notes that while nausea and vomiting were the most common reasons for discontinuation across antidepressant trials generally, mirtazapine was specifically identified as having a more favorable gastrointestinal profile than comparators.
When directly compared:
- Venlafaxine had a higher incidence of nausea and vomiting than other SSRIs
- Sertraline had higher rates of diarrhea than mirtazapine
- Mirtazapine was not associated with increased GI adverse effects 4
FDA Drug Label Information
The FDA-approved drug label for mirtazapine lists nausea, vomiting, and diarrhea as potential symptoms of serotonin syndrome (a serious drug interaction) rather than as common side effects of the medication itself 1. The label also mentions nausea and vomiting as potential symptoms of discontinuation syndrome when stopping mirtazapine abruptly 1.
The most common side effects listed in the FDA label are:
- Sleepiness
- Increased appetite
- Weight gain
- Dizziness
Notably absent from this list are nausea and vomiting 1.
Clinical Safety Profile
A comprehensive safety review of mirtazapine's clinical trial program found that typical SSRI adverse events—including nausea, vomiting, diarrhea, and insomnia—were actually registered less frequently in mirtazapine-treated patients than in placebo-treated patients 2. This is a remarkable finding that underscores mirtazapine's favorable GI tolerability profile.
Emerging Therapeutic Use for Nausea
Recent evidence suggests mirtazapine may actually be therapeutic for nausea and vomiting. Case reports demonstrate successful use of mirtazapine 15 mg for severe nausea and vomiting during pregnancy when standard antiemetics failed, with rapid symptom improvement and minimal side effects 3. This antiemetic property is attributed to mirtazapine's antagonism of 5-HT3 receptors.
Important Caveats
If vomiting occurs in a patient taking mirtazapine, consider:
Serotonin syndrome - especially if the patient is on multiple serotonergic medications. Look for accompanying symptoms: agitation, confusion, tachycardia, hyperthermia, tremor, or muscle rigidity. This is a medical emergency requiring immediate discontinuation and supportive care 1.
Discontinuation syndrome - if the patient recently stopped or reduced mirtazapine abruptly. Other symptoms include dizziness, anxiety, electric shock sensations, and confusion 1.
Unrelated causes - given mirtazapine's favorable GI profile, vomiting is more likely due to another etiology (gastroenteritis, other medications, underlying medical conditions).
The bottom line: Vomiting is not a characteristic adverse effect of mirtazapine and should prompt investigation for alternative causes or serious drug interactions rather than being attributed to the medication itself.