Pharmacologic class (EPC) · 5 drug pages

5-alpha reductase inhibitor: adverse event reports filed with FDA

24,827 reports list a drug in this class as a suspect or interacting product, 2004–2026.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

24,827
reports across the class: 0.1% of all reports; 2,857
reports, 12 months to June 2026: 5,286 in the 12 months before; 62.8%
marked serious by the reporter: 57.4% across all reports; 5
drugs with a page: brand and generic names counted separately

5-alpha reductase inhibitor is a pharmacologic class (an FDA Established Pharmacologic Class) with 5 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 24,827 adverse event reports received by FDA, 0.1% of the database, from January 2004 to June 2026.

2,857 reports arrived in the 12 months to June 2026, down 46% from 5,286 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 62.8% of the class's reports are marked serious, 4.8% record death among the outcomes and 15.3% record hospitalisation, as reported.

Across the class the reactions recorded most often are erectile dysfunction (19.3%), depression (15.2%) and anxiety (12.4%). The class median share shown beside each term is the middle value across the member drugs; it is the comparison used on every drug page in this class.

The members table is ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Drugs in the class

Drug	Name type	Reports	Latest 12 months	Marked serious	Top term recorded
Finasteride	generic	15,517	2,671	59.9%	Adverse drug reaction
PropeciaFinasteride	brand	4,320	18	67.4%	Erectile dysfunction
Dutasteride	generic	2,726	151	74.7%	Dyspnoea
ProscarFinasteride	brand	1,685	17	73.4%	Erectile dysfunction
JalynDutasteride and tamsulosin hydrochloride	brand	579	0	20.4%	Drug ineffective

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Reactions recorded across the class

share of class reports recording the termmedian drug in the class

Erectile dysfunctiondifficulty getting or keeping an erection19.3%4,796
Depressionlow mood15.2%3,764
Anxietyanxiety12.4%3,089
Sexual dysfunctiona sexual problem12.1%3,007
Adverse drug reactiona harmful or unpleasant reaction reported to a medicine10.5%2,619
Libido decreasedreduced sex drive7.8%1,944
Loss of libido7.7%1,911
Fatiguetiredness7.7%1,908
Cognitive disorderproblems with thinking or memory7.4%1,831
Insomniadifficulty sleeping7.3%1,802
Suicidal ideationthoughts of suicide6.6%1,650
Adverse eventan unwanted medical event, type not specified6.2%1,529
Dizzinesslight-headedness or unsteadiness4.3%1,057
Dyspnoeashortness of breath3.8%944
Drug ineffectivethe medicine did not work as expected3.8%935
Astheniaweakness or lack of energy3.7%919
Ejaculation disorder3.6%885
Headachehead pain3.5%875
Testicular pain3.3%817
Arthralgiajoint pain3.2%789
Gynaecomastiabreast enlargement in men3.1%758
Ejaculation failure2.6%646
Semen volume decreased2.5%625
Tinnitusringing in the ears2.4%584
Asthmaasthma2.3%578

Solid bar: share of all class reports. Hollow bar: the median share across the 5 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death4.8%1,180

Life-threatening5.8%1,433

Hospitalisation (initial or prolonged)15.3%3,793

Disability15%3,728

Congenital anomaly0.7%182

Other serious47.7%11,843

Not serious37.2%9,239

Patient age

Under 20.2%40

2 to 110.2%51

12 to 170.1%37

18 to 4417.5%4,351

45 to 647.7%1,915

65 to 748.2%2,025

75 and over10%2,495

Age not given56%13,913

Who reported

Physician17.8%4,422

Pharmacist5.6%1,391

Other health professional11.9%2,950

Lawyer1.5%374

Consumer or non-health professional60.8%15,083

Not given2.4%607

Grey bar: all 20,646,523 reports in the database. Outcome flags are as the reporter set them and are not verified by FDA.

Questions about 5-alpha reductase inhibitor reports

Which drugs are in the 5-alpha reductase inhibitor class on this site?

Finasteride, Propecia, Dutasteride, Proscar and Jalyn. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

24,827 reports through June 2026, 2,857 of them in the latest 12 months. A report listing two drugs of the class counts once for each.

What reactions are recorded most often?

erectile dysfunction (19.3%), depression (15.2%), anxiety (12.4%), sexual dysfunction (12.1%) and adverse drug reaction (10.5%).

Can the members table be used to rank the drugs?

No. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." Drugs differ in how many people take them, in the conditions they treat, in time on the market and in how diligently reports are collected.

How do I report an adverse event?

Through FDA MedWatch (Form FDA 3500, or 1-800-FDA-1088) or to the manufacturer. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A class is the Established Pharmacologic Class most often attached to a drug's reports by openFDA's label harmonisation, or from the NDC Directory where reports carry none. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.