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Phenelzine Side Effects

The most commonly reported side effects of phenelzine include depression, pharmaceutical product complaint, and anxiety, based on 1,864 FDA adverse event reports from 2004 to 2025. 10.9% of reports found the drug to be ineffective.

Phenelzine side effects

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

1
Drug Ineffective10.9%204
2
Drug Ineffective9.4%176
3
Depression7.6%141
4
Pharmaceutical Product Complaint5.4%100
5
Anxiety4.7%88
6
Drug Interaction4.6%85
7
Headache4.5%83
8
Insomnia3.9%73
9
Headache3.8%71
10
Depression3.6%67
11
Weight Increased3.5%66
12
Weight Increased3.4%63
13
Feeling Abnormal3.3%62
14
Off Label Use3.3%62
15
Drug Interaction3.2%60

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

Report severity

61.1%Serious1,139 reports
24.3%Hospitalizations453 reports
4.3%Fatal81 reports

Seriousness is determined by the reporter, not by OpenClaim.

Phenelzine drug interactions

Other drugs that appear in adverse event reports alongside phenelzine. 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-fumarate4.5%83
2
Lithium3.2%59
3
Lamotrigine2.6%48
4
Olanzapine2.6%48
5
Fluoxetine-hydrochloride2.3%43
6
Aripiprazole2.3%43
7
Duloxetine-hydrochloride2.2%41
8
Venlafaxine2.1%40
9
Alprazolam2.1%39
10
Sertraline-hydrochloride1.9%36
11
Clonazepam1.8%34
12
Gabapentin1.7%32
13
Escitalopram-oxalate1.6%30
14
Levothyroxine-sodium1.5%28
15
Tranylcypromine-sulfate1.4%27

Taken alongside

1
Levothyroxine-sodium7.6%141
2
Clonazepam7.0%130
3
Alprazolam6.3%118
4
Acetaminophen5.4%100
5
Aspirin4.6%85
6
Lorazepam4.0%75
7
Diazepam3.9%72
8
Omeprazole3.8%70
9
Lithium3.5%66
10
Gabapentin3.3%62
11
Ergocalciferol3.3%62
12
Furosemide3.3%61
13
Quetiapine-fumarate2.8%53
14
Lamotrigine2.6%49
15
Zolpidem-tartrate2.6%49

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 phenelzine side effects

56.6% of phenelzine adverse event reports involve female patients and 36.1% involve male patients. The largest age group is adult at 63%. These figures reflect who reports side effects, not underlying risk.

Sex

Female56.6%
Male36.1%
Unknown7.3%

Age group

< 20.2%
2–110.1%
12–170.8%
18–6463.3%
65+35.6%

What is phenelzine used for

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

Affective DisorderAgitationAgoraphobiaAntidepressant TherapyAnxietyAnxiety DisorderAnxiolytic TherapyAstheniaAttention Deficit/hyperactivity DisorderAutonomic Nervous System ImbalanceAgoraphobiaAntidepressant TherapyAntipsychotic TherapyAnxietyAnxiety Disorder

Showing 15 of 102 indications

Phenelzine brand names and reporting trend

Phenelzine is sold under the brand name Nardil.

Brand names

Nardil751

Quarterly reports (20042025)

20052010201520202025

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

Taking phenelzine with another medication?

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