Pharmacologic class (EPC) · 7 drug pages

Thiazide diuretic: adverse event reports filed with FDA

33,516 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.

33,516
reports across the class: 0.2% of all reports; 1,412
reports, 12 months to June 2026: 1,644 in the 12 months before; 84%
marked serious by the reporter: 57.4% across all reports; 7
drugs with a page: brand and generic names counted separately

Thiazide diuretic is a pharmacologic class (an FDA Established Pharmacologic Class) with 7 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 33,516 adverse event reports received by FDA, 0.2% of the database, from January 2004 to June 2026.

1,412 reports arrived in the 12 months to June 2026, down 14% from 1,644 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 84% of the class's reports are marked serious, 8.9% record death among the outcomes and 49.6% record hospitalisation, as reported.

Across the class the reactions recorded most often are acute kidney injury (8.3%), sprue-like enteropathy (7.9%) and drug ineffective (7.9%). 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
Hydrochlorothiazide	generic	22,639	1,296	88.4%	Hyponatraemia
Benicar HCTOlmesartan medoxomil-hydrochlorothiazide	brand	5,001	12	75.9%	Sprue-like enteropathy
HyzaarLosartan potassium and hydrochlorothiazide	brand	1,661	15	80.6%	Drug ineffective
Lisinopril and hydrochlorothiazide	generic	1,636	65	71%	Angioedema
Atacand HctCandesartan cilexetil and hydrochlorothiazide	brand	1,257	3	75.6%	Drug ineffective
Losartan potassium and hydrochlorothiazide	generic	705	15	66.8%	Drug ineffective
TribenzorOlmesartan medoxomil / amlodipine besylate / hydrochlorothiazide	brand	617	6	66%	Sprue-like enteropathy

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

Acute kidney injurysudden loss of kidney function8.3%2,786
Sprue-like enteropathy7.9%2,643
Drug ineffectivethe medicine did not work as expected7.9%2,634
Dizzinesslight-headedness or unsteadiness7.7%2,586
Hyponatraemialow blood sodium7.6%2,535
Hypotensionlow blood pressure6.7%2,234
Nauseafeeling sick6.6%2,201
Diarrhoealoose or frequent stools5.9%1,966
Headachehead pain5.7%1,900
Dyspnoeashortness of breath5.7%1,899
Gastrooesophageal reflux diseaseacid reflux5.3%1,776
Fatiguetiredness5%1,674
Malaisegeneral feeling of being unwell4.9%1,632
Vomitingbeing sick4.6%1,532
Drug interactionan interaction between medicines4.5%1,496
Falla fall4.4%1,480
Weight decreasedweight loss4.1%1,365
Hypokalaemialow blood potassium4%1,347
Dehydrationdehydration3.9%1,306
Blood pressure increaseda raised blood pressure reading3.8%1,289
Off label useused for a purpose or in a way not on the label3.7%1,251
Arthralgiajoint pain3.7%1,249
Syncopefainting3.7%1,233
Hypertensionhigh blood pressure3.6%1,214
Astheniaweakness or lack of energy3.6%1,191

Solid bar: share of all class reports. Hollow bar: the median share across the 7 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death8.9%2,976

Life-threatening6.9%2,326

Hospitalisation (initial or prolonged)49.6%16,615

Disability2.4%802

Congenital anomaly0.6%188

Other serious49.2%16,484

Not serious16%5,378

Patient age

Under 20.3%100

2 to 110.3%88

12 to 170.4%142

18 to 444.7%1,582

45 to 6422.5%7,557

65 to 7416.6%5,572

75 and over19.5%6,539

Age not given35.6%11,936

Who reported

Physician31.4%10,513

Pharmacist10.8%3,628

Other health professional23.7%7,948

Lawyer2.2%743

Consumer or non-health professional26.6%8,902

Not given5.3%1,782

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 Thiazide diuretic reports

Which drugs are in the Thiazide diuretic class on this site?

Hydrochlorothiazide, Benicar HCT, Hyzaar, Lisinopril and hydrochlorothiazide, Atacand Hct and Losartan potassium and hydrochlorothiazide and 1 more. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

33,516 reports through June 2026, 1,412 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?

acute kidney injury (8.3%), sprue-like enteropathy (7.9%), drug ineffective (7.9%), dizziness (7.7%) and hyponatraemia (7.6%).

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.