OpenClaim

Phenoxybenzamine Side Effects

The most commonly reported side effects of phenoxybenzamine include premature baby, foetal exposure during pregnancy, and nausea, based on 217 FDA adverse event reports from 2004 to 2025. 10.6% of reports found the drug to be ineffective.

Phenoxybenzamine side effects

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

1
Drug Ineffective10.6%23
2
Premature Baby5.5%12
3
Foetal Exposure During Pregnancy5.5%12
4
Nausea5.5%12
5
Fatigue4.6%10
6
Asthenia4.1%9
7
Hypertension4.1%9
8
Maternal Exposure During Pregnancy4.1%9
9
Vomiting4.1%9
10
Diarrhoea4.1%9
11
Dehydration3.7%8
12
Hypotension3.7%8
13
Low Birth Weight Baby3.7%8
14
Phaeochromocytoma3.7%8
15
Dizziness3.7%8

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

Report severity

87.6%Serious190 reports
42.4%Hospitalizations92 reports
10.1%Fatal22 reports

Seriousness is determined by the reporter, not by OpenClaim.

Phenoxybenzamine drug interactions

Other drugs that appear in adverse event reports alongside phenoxybenzamine. 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
Metoprolol10.6%23
2
Labetalol-hydrochloride9.2%20
3
Propranolol-hydrochloride8.8%19
4
Amlodipine6.9%15
5
Hydralazine-hydrochloride6.0%13
6
Nifedipine5.1%11
7
Fentanyl4.6%10
8
Prazosin-hydrochloride4.6%10
9
Methyldopa4.1%9
10
Prednisone4.1%9
11
Magnesium-sulfate4.1%9
12
Nitroglycerin3.7%8
13
Digoxin3.2%7
14
Lorazepam3.2%7
15
Dicyclomine-hydrochloride3.2%7

Taken alongside

1
Acetaminophen10.6%23
2
Furosemide8.8%19
3
Levothyroxine-sodium8.8%19
4
Aspirin8.3%18
5
Amlodipine7.8%17
6
Metoprolol7.8%17
7
Omeprazole7.8%17
8
Ergocalciferol7.8%17
9
Ondansetron7.4%16
10
Fentanyl6.5%14
11
Pantoprazole-sodium6.5%14
12
Lorazepam6.0%13
13
Potassium-chloride6.0%13
14
Albuterol6.0%13
15
Metformin5.5%12

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 phenoxybenzamine side effects

57.6% of phenoxybenzamine adverse event reports involve female patients and 30.9% involve male patients. The largest age group is adult at 69%. These figures reflect who reports side effects, not underlying risk.

Sex

Female57.6%
Male30.9%
Unknown11.5%

Age group

< 25.5%
2–113.1%
12–171.2%
18–6468.7%
65+21.5%

What is phenoxybenzamine used for

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

Adrenal MassAngina PectorisAnticoagulant TherapyBlood Pressure FluctuationBenign Prostatic HyperplasiaCellulitisCushing^s SyndromeEjection FractionEssential HypertensionFoetal Exposure During PregnancyHyperadrenalismHypertensionHypertensive EmergencyHypertensionHypertensive Crisis

Showing 15 of 44 indications

Phenoxybenzamine brand names and reporting trend

Phenoxybenzamine is sold under the brand name Phenoxybenzamine Hydrochloride.

Brand names

Phenoxybenzamine Hydrochloride21

Quarterly reports (20042025)

20042010201520202025

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

Taking phenoxybenzamine with another medication?

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