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Mirtazapine Side Effects

The most commonly reported side effects of mirtazapine include fatigue, nausea, and off label use, based on 93,750 FDA adverse event reports from 2004 to 2025. 4.6% of reports found the drug to be ineffective.

#1 Reported: FatigueAll side effects ↓Top Co-Medication: Quetiapine-fumarateDrug interactions ↓56% of Reports Are AdultDemographics ↓

Mirtazapine side effects

Percentages show how often each reaction appears relative to total reports for mirtazapine.

1
Fatigue4.7%4,447
2
Nausea4.6%4,334
3
Drug Ineffective4.6%4,277
4
Off Label Use4.1%3,874
5
Diarrhoea4.0%3,771
6
Fall4.0%3,748
7
Toxicity To Various Agents4.0%3,739
8
Death3.4%3,172
9
Dizziness3.4%3,157
10
Dyspnoea3.3%3,119
11
Anxiety3.2%2,958
12
Vomiting3.0%2,837
13
Drug Interaction3.0%2,783
14
Somnolence2.9%2,732
15
Headache2.9%2,731

These are voluntary reports and do not establish that mirtazapine caused these reactions.

Report severity

84.4%Serious79,089 reports
41.5%Hospitalizations38,864 reports
15.2%Fatal14,287 reports

Seriousness is determined by the reporter, not by OpenClaim.

Mirtazapine drug interactions

Other drugs that appear in adverse event reports alongside mirtazapine. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Quetiapine-fumarate6.4%6,026
2
Venlafaxine4.5%4,173
3
Olanzapine3.8%3,598
4
Sertraline-hydrochloride3.5%3,290
5
Pregabalin3.1%2,863
6
Risperidone2.7%2,507
7
Diazepam2.6%2,443
8
Acetaminophen2.4%2,254
9
Lorazepam2.4%2,209
10
Duloxetine-hydrochloride2.3%2,197
11
Lenalidomide2.3%2,186
12
Aripiprazole2.3%2,185
13
Citalopram-hydrobromide2.3%2,128
14
Gabapentin2.3%2,127
15
Escitalopram-oxalate2.1%1,984

Taken alongside

1
Acetaminophen12.8%12,035
2
Aspirin10.3%9,646
3
Omeprazole9.7%9,093
4
Levothyroxine-sodium9.3%8,729
5
Atorvastatin-calcium8.8%8,211
6
Pantoprazole-sodium8.6%8,088
7
Gabapentin8.1%7,605
8
Ergocalciferol7.7%7,229
9
Albuterol7.6%7,100
10
Furosemide7.0%6,534
11
Amlodipine6.9%6,485
12
Lorazepam6.9%6,429
13
Metoprolol6.4%5,987
14
Clonazepam5.6%5,277
15
Ondansetron5.5%5,196

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports mirtazapine side effects

52.9% of mirtazapine adverse event reports involve female patients and 39.0% involve male patients. The largest age group is adult at 56%. These figures reflect who reports side effects, not underlying risk.

Sex

Female52.9%
Male39.0%
Unknown8.0%

Age group

< 20.8%
2–110.3%
12–171.3%
18–6456.4%
65+41.2%

What is mirtazapine used for

Conditions and purposes for which patients were taking mirtazapine when the adverse event was reported.

Abdominal DiscomfortAbdominal PainAbdominal Pain UpperAbdominal Wall DisorderAbnormal BehaviourAccidental Drug Intake By ChildAccidental ExposureAccidental Exposure To ProductAccidental Exposure To Product By ChildAccidental OverdoseAccidental PoisoningAcne FulminansAcute PsychosisAdjustment DisorderAdjustment Disorder With Anxiety

Showing 15 of 935 indications

Mirtazapine brand names and reporting trend

Mirtazapine is sold under the brand name Remeron Soltab.

Brand names

Remeron Soltab87,018

Quarterly reports (2004–2025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking mirtazapine with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.

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