OpenClaim

Prazosin Side Effects

The most commonly reported side effects of prazosin include off label use, nausea, and fatigue, based on 9,550 FDA adverse event reports from 2004 to 2025. 5.5% of reports found the drug to be ineffective.

Prazosin side effects

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

1
Drug Ineffective5.5%523
2
Off Label Use5.4%513
3
Nausea5.3%509
4
Fatigue4.5%432
5
Headache3.9%373
6
Pain3.9%372
7
Anxiety3.9%371
8
Dizziness3.9%371
9
Diarrhoea3.7%355
10
Depression3.5%332
11
Vomiting3.4%327
12
Dyspnoea3.3%315
13
Fall3.2%303
14
Hypotension3.0%287
15
Suicidal Ideation2.9%279

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

Report severity

72.8%Serious6,949 reports
36.6%Hospitalizations3,491 reports
10.7%Fatal1,020 reports

Seriousness is determined by the reporter, not by OpenClaim.

Prazosin drug interactions

Other drugs that appear in adverse event reports alongside prazosin. 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
Sodium-oxybate5.8%554
2
Quetiapine-fumarate4.8%457
3
Amlodipine2.6%251
4
Metoprolol2.5%239
5
Metformin2.5%234
6
Aripiprazole2.5%234
7
Furosemide2.3%223
8
Bupropion2.3%221
9
Mirtazapine2.2%210
10
Fluoxetine-hydrochloride2.2%206
11
Omeprazole2.2%206
12
Sertraline-hydrochloride2.1%198
13
Dupilumab2.0%189
14
Dextrose2.0%188
15
Adalimumab2.0%187

Taken alongside

1
Gabapentin14.8%1,410
2
Acetaminophen13.9%1,330
3
Albuterol12.8%1,225
4
Omeprazole12.8%1,221
5
Ergocalciferol11.6%1,105
6
Aspirin11.4%1,084
7
Trazodone-hydrochloride10.5%1,006
8
Atorvastatin-calcium10.5%1,001
9
Amlodipine10.5%999
10
Clonazepam9.9%941
11
Levothyroxine-sodium9.4%899
12
Furosemide9.0%860
13
Fluticasone8.9%854
14
Quetiapine-fumarate8.8%836
15
Metoprolol8.5%810

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 prazosin side effects

51.7% of prazosin adverse event reports involve female patients and 40.9% involve male patients. The largest age group is adult at 70%. These figures reflect who reports side effects, not underlying risk.

Sex

Female51.7%
Male40.9%
Unknown7.4%

Age group

< 20.9%
2–111.4%
12–172.6%
18–6470.1%
65+25.1%

What is prazosin used for

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

Abnormal DreamsAffective DisorderAggressionAgitationAntidepressant TherapyAnxietyAortic DissectionAutismAbnormal DreamsAdverse Drug ReactionAffective DisorderAgitationAlcoholismAnxietyAnxiolytic Therapy

Showing 15 of 251 indications

Prazosin brand names and reporting trend

Quarterly reports (20042025)

20052010201520202025

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

Taking prazosin with another medication?

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