Hydrochlorothiazide: adverse event reports that FDA received

Name: Hydrochlorothiazide: adverse event reports that FDA received, by year and species
Creator: Pet Drug Reports
License: https://creativecommons.org/publicdomain/zero/1.0/

Active ingredient

The Green Book lists no brand name for exactly this active ingredient.

The openFDA records give the value "MSK" for the brand name and for the manufacturer name of each drug. FDA says that MSK means "masked". So the site cannot count a report for a brand.

Read this first. FDA says this about the data:

An API dataset query result cannot be used to estimate the risk associated with the product or compare one drug or device product with another. When looking at the results, be aware that there is no certainty that the reported drug or device caused the adverse event. This dataset should not be the sole source of information for clinical decision-making or other assumptions about the safety or effectiveness of a product. The adverse event may have been related to an underlying disease, other drugs used at the same time or other non-drug related sources.
FDA Center for Veterinary Medicine publishes these words. Source: Adverse Event Reports for Animal Drugs and Devices, read on 2 Oct 2026. The data have the reports that FDA received through 31 Mar 2026.

This page is not veterinary advice. For an animal that is ill, speak to a veterinarian.

Contacting a veterinarian How to report to FDA

From December 2011 to December 2025, FDA received 33 adverse event reports that name a drug with hydrochlorothiazide as its active ingredient. Of the 33 reports, 24 (72.7%) are about people who were exposed to the drug. 8 reports are about dogs (24.2%).

In January to March 2026, FDA received no reports that name this drug. The signs that appear in the largest number of the 33 reports are "Accidental exposure" and "Other abnormal test result NOS". A report is not proof that a drug caused a sign.

This page has fewer than 50 reports. The site keeps the page for its links and keeps it out of search engines.

Since the last update of the FDA data

No update is on record. The record starts when FDA adds the reports of April to June 2026.

January to March 2026 is the latest closed quarter in the data. In that quarter FDA received 0 reports that name hydrochlorothiazide: 0 dog, 0 cat, 0 horse, 0 other or not given.

All updates Feed of updates (RSS)

Signs that the reports list

A sign is a coded term from the report. The words in brackets are a plain gloss of the term. The percentage is the share of the 33 reports that list the sign. One report can list more than one sign.

The sign that is in the largest number of the reports comes first.

Accidental exposure[exposure that was not intended]33.3%11 reports
Other abnormal test result NOS[abnormal laboratory result, type not specified]18.2%6 reports
Hyperglycaemia[high blood sugar]12.1%4 reports
Lethargy[unusually tired or inactive]12.1%4 reports
Vomiting12.1%4 reports
Death9.1%3 reports
Death by euthanasia[the animal was euthanized]9.1%3 reports
Elevated serum alkaline phosphatase (SAP)[a liver and bone enzyme above the normal range]9.1%3 reports
Glucosuria[sugar in the urine]9.1%3 reports
Intentional misuse[use that was knowingly different from the label]9.1%3 reports
Nausea9.1%3 reports
Weakness9.1%3 reports
Weight loss9.1%3 reports
Anorexia[not eating]6.1%2 reports

Show the next 16 signs

Ataxia[unsteady, uncoordinated movement]6.1%2 reports
Azotaemia[raised kidney values in blood]6.1%2 reports
Bad taste6.1%2 reports
Chest discomfort NOS[NOS: not otherwise specified]6.1%2 reports
Constipation6.1%2 reports
Cough6.1%2 reports
Dazed6.1%2 reports
Diabetes6.1%2 reports
Diarrhoea[diarrhea]6.1%2 reports
Dizziness6.1%2 reports
Elevated alanine aminotransferase (ALT)[a liver enzyme above the normal range]6.1%2 reports
Hemiparesis (weakness L or R side)6.1%2 reports
Hypokalaemia[low blood potassium]6.1%2 reports
Hyponatremia[low blood sodium]6.1%2 reports
Inappropriate urination6.1%2 reports
Injection site swelling[swelling where the injection was given]6.1%2 reports

The list shows 30 of 114 coded signs. A report is not proof that a drug caused a sign. Download all signs (CSV)

Reports by species

Human exposure72.7%24
Dog24.2%8
Cat3%1

The share is of all 33 reports that name hydrochlorothiazide. The other reports give a different species or no species.

Reports for each month, Apr 2021 to Mar 2026

Dog2 reports

No chart: no month has 5 or more reports.

Cat1 report

No chart: no month has 5 or more reports.

Horse0 reports

No chart: no month has 5 or more reports.

Other or not given6 reports

No chart: no month has 5 or more reports.

The month is the month in which FDA received the report. Each chart has its own scale. FDA says that a report can take 3 to 6 months to reach the public data. The newest months can get more reports in a later update.

Reports by year

Dog
Cat
Horse
Other or not given

Reports that name hydrochlorothiazide, by the year in which FDA received them and by species
Year	Dog	Cat	Other or not given	All species
2025	1	1	3	5
2024	1	0	1	2
2022	0	0	2	2
2021	0	0	1	1
2020	1	0	4	5
2019	0	0	1	1
2018	1	0	5	6
2016	1	0	0	1
2015	0	0	1	1
2014	2	0	2	4
2012	0	0	4	4
2011	1	0	0	1

2025 has the reports that FDA received through Dec 2025. Download the years (CSV)

What the reports record

Outcome at the time of the report

Recovered/Normal27.3%9
Recovered with Sequela[recovered, with a lasting effect]9.1%3
Ongoing12.1%4
Died9.1%3
Euthanized9.1%3
Outcome Unknown42.4%14

An outcome in a report is not proof that the drug caused it. The person who sends the report gives the outcome. Each share is of the 33 reports that name hydrochlorothiazide.

A report about more than one animal can have more than one outcome.

Kind of report

Safety issue93.9%31
Lack of expected effectiveness0%0
Both safety and lack of expected effectiveness3%1
Manufacturing or product defect3%1
Other0%0

33 reports say if the event was serious. 42.4% of them have the serious flag. The person who sends the report sets the flag.

Show age, weight, breed and route

Age of the animal

Under 1 year3%1
1 to 3 years0%0
4 to 7 years0%0
8 to 11 years18.2%6
12 years and over75.8%25
Age not given3%1

Weight of the animal

Under 5 kg (11 lb)3%1
5 to 9.9 kg (11 to 22 lb)18.2%6
10 to 24.9 kg (22 to 55 lb)3%1
25 to 44.9 kg (55 to 99 lb)3%1
45 kg and over (99 lb and over)36.4%12
Weight not given36.4%12

Breed, where the report gives one breed

A breed with many animals has many reports.

Route in the report

Oral57.6%19

Each bar is on a scale of 0 to 100%.

Approved animal drugs with this active ingredient (FDA Green Book)

This section is reference data. It has no report count.

The openFDA records give the value "MSK" for the brand name and for the manufacturer name of each drug. FDA says that MSK means "masked". So the site cannot count a report for a brand.

Applications in the Green Book of 1 Oct 2026, pioneer applications (NADA) first
Brand name	Active ingredients	Sponsor	Approved species	Application
Hydrozide Injectionapproval withdrawn	Hydrochlorothiazide	Boehringer Ingelheim Animal Health USA Inc.	Cattle	NADA 013-674

FDA pages for this drug

How to Report Animal Drug and Device Side Effects and Product ProblemsThe FDA page that tells an owner or a veterinarian how to send a report.
Animal Drugs @ FDAThe search page of the Green Book, the FDA list of approved animal drugs.

The site checked these addresses on 2 Oct 2026. The links open in a new tab.

Cite this page

Pet Drug Reports. Hydrochlorothiazide: adverse event reports that FDA received. https://petdrugreports.com/drug/hydrochlorothiazide/ Source: FDA Center for Veterinary Medicine, openFDA Animal and Veterinary adverse event reports, export of 28 Sep 2026. Reports received through 31 Mar 2026.

Where the data come from

The counts come from the openFDA Animal and Veterinary adverse event files, export of 28 Sep 2026. The files have the reports that the FDA Center for Veterinary Medicine received through 31 Mar 2026. The files mask brand and manufacturer names. The site counts a drug by the active ingredients that each record gives, and gives no count to a brand, an application or a company. Ingredient names and the lists of approved products follow the FDA Green Book of 1 Oct 2026. The site does not use the application number that a record has.

The site does not publish report text, lot numbers or details of a reporter. FDA's record is the authority. See how the site counts reports, the data sources and the corrections page.

Questions about these reports

Which brand are these reports about?: The openFDA records give the value "MSK" for the brand name and for the manufacturer name of each drug. FDA says that MSK means "masked". So the site cannot count a report for a brand. The Green Book lists no brand name for exactly this active ingredient.
Do the reports show that the drug caused the signs?: No. FDA states this about the data.
When looking at the results, be aware that there is no certainty that the reported drug or device caused the adverse event.
The adverse event may have been related to an underlying disease, other drugs used at the same time or other non-drug related sources.
FDA Center for Veterinary Medicine. Source: Adverse Event Reports for Animal Drugs and Devices
How many reports did FDA receive in the latest 12 months?: FDA received 4 reports in the 12 months to March 2026. It received 2 reports in the 12 months before. FDA says that a report can take 3 to 6 months to reach the public data. The newest months can get more reports in a later update.
What kinds of report are in the count?: Of the 33 reports received from December 2011 to December 2025, 93.9% are about a safety issue only. 3% are about a lack of expected effectiveness, alone or with a safety issue. 3% are about a defect of the product or its package.