Pharmacologic class (EPC) · 3 drug pages

Cytochrome P450 17A1 inhibitor: adverse event reports filed with FDA

37,351 reports list a drug in this class as a suspect or interacting product, 2010–2026.

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.

37,351
reports across the class: 0.2% of all reports; 1,254
reports, 12 months to June 2026: 1,390 in the 12 months before; 68.2%
marked serious by the reporter: 57.4% across all reports; 3
drugs with a page: brand and generic names counted separately

Cytochrome P450 17A1 inhibitor is a pharmacologic class (an FDA Established Pharmacologic Class) with 3 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 37,351 adverse event reports received by FDA, 0.2% of the database, from May 2010 to June 2026.

1,254 reports arrived in the 12 months to June 2026, down 10% from 1,390 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 68.2% of the class's reports are marked serious, 20.6% record death among the outcomes and 27% record hospitalisation, as reported.

Across the class the reactions recorded most often are death (15.6%), fatigue (5.6%) and drug ineffective (4.9%). 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
ZytigaAbiraterone acetate	brand	25,259	183	63.4%	Death
Abiraterone	generic	6,436	615	69.9%	Death
Abiraterone acetate	generic	5,656	456	88.1%	Death

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

Deaththe patient died; cause not stated by this term15.6%5,822
Fatiguetiredness5.6%2,102
Drug ineffectivethe medicine did not work as expected4.9%1,826
Prostatic specific antigen increased4.7%1,750
Therapy cessation4.2%1,577
Disease progressionthe disease advanced3.2%1,200
Hospitalisationadmission to hospital2.9%1,066
Hot flusha hot flush2.8%1,062
Astheniaweakness or lack of energy2.7%995
Off label useused for a purpose or in a way not on the label2.4%885
Falla fall2.2%832
Nauseafeeling sick2.2%821
Diarrhoealoose or frequent stools2.2%804
Hypertensionhigh blood pressure2%734
Prostate cancer2%734
Hypokalaemialow blood potassium1.9%720
Dizzinesslight-headedness or unsteadiness1.8%688
Pneumonialung infection1.8%671
Dyspnoeashortness of breath1.8%664
Urinary tract infectionbladder or urinary infection1.8%664
Decreased appetitereduced appetite1.6%602
Anaemialow red blood cells1.5%553
Vomitingbeing sick1.5%548
Prostate cancer metastatic1.5%543
Drug dose omissiona dose was missed1.4%535

Solid bar: share of all class reports. Hollow bar: the median share across the 3 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death20.6%7,678

Life-threatening2.7%995

Hospitalisation (initial or prolonged)27%10,069

Disability0.7%269

Congenital anomaly0%3

Other serious30.5%11,398

Not serious31.8%11,865

Patient age

Under 20%8

2 to 110%1

12 to 170%2

18 to 440.1%52

45 to 648.5%3,181

65 to 7418%6,735

75 and over30.9%11,555

Age not given42.3%15,817

Who reported

Physician20.5%7,651

Pharmacist14.1%5,280

Other health professional22.6%8,436

Lawyer0%8

Consumer or non-health professional32.9%12,291

Not given9.9%3,685

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 Cytochrome P450 17A1 inhibitor reports

Which drugs are in the Cytochrome P450 17A1 inhibitor class on this site?

Zytiga, Abiraterone and Abiraterone acetate. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

37,351 reports through June 2026, 1,254 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?

death (15.6%), fatigue (5.6%), drug ineffective (4.9%), prostatic specific antigen increased (4.7%) and therapy cessation (4.2%).

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.