N-butyl Chloride (Happy Jack Worm, NBC Kaps Wormer): adverse event reports that FDA received

Name: N-butyl Chloride: 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 names in brackets are brand names with 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 May 1987 to March 2000, FDA received 43 adverse event reports that name a drug with n-butyl chloride as its active ingredient. Of the 43 reports, 24 (55.8%) are about dogs. 17 reports are about cats (39.5%).

In January to March 2026, FDA received no reports that name this drug. The signs that appear in the largest number of the 43 reports are "Vomiting", "Death" and "Anorexia". 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 n-butyl chloride: 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 43 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.

Vomiting41.9%18 reports
Death27.9%12 reports
Anorexia[not eating]16.3%7 reports
Hypersalivation[drooling]14%6 reports
Dehydration11.6%5 reports
Depression[dull, quiet or withdrawn]11.6%5 reports
Blood in vomit4.7%2 reports
Bloody diarrhoea[diarrhea with blood]4.7%2 reports
Convulsion[seizure]4.7%2 reports
Diarrhoea[diarrhea]4.7%2 reports
Dyspnoea[difficulty breathing]4.7%2 reports
Hyperactivity4.7%2 reports
Malaise[generally unwell]4.7%2 reports
Weakness4.7%2 reports

Show the next 16 signs

Adipsia[not drinking]2.3%1 reports
Anaphylaxis[sudden severe allergic-type reaction]2.3%1 reports
Ataxia[unsteady, uncoordinated movement]2.3%1 reports
Death by euthanasia[the animal was euthanized]2.3%1 reports
Defect Unknown/Not Specified[a product quality report, not a sign in an animal]2.3%1 reports
Fever2.3%1 reports
Gagging2.3%1 reports
Gastric bloat2.3%1 reports
Haemoptysis2.3%1 reports
Haemorrhage NOS[NOS: not otherwise specified]2.3%1 reports
Ineffective, worms NOS[legacy FDA term: the product did not have the expected effect (worms nos)]2.3%1 reports
Lack of efficacy (endoparasite) - hookworm[the product did not have the expected effect: hookworms]2.3%1 reports
Lack of efficacy - NOS[the product did not have the expected effect]2.3%1 reports
Pain NOS[NOS: not otherwise specified]2.3%1 reports
Regurgitation2.3%1 reports
Staggering2.3%1 reports

The list shows 30 of 33 coded signs. A report is not proof that a drug caused a sign. Download all signs (CSV)

Reports by species

Dog55.8%24
Cat39.5%17
Human exposure2.3%1
Other2.3%1

The share is of all 43 reports that name n-butyl chloride. The other reports give a different species or no species.

Reports for each month, Apr 2021 to Mar 2026

Dog0 reports

No chart: no month has 5 or more reports.

Cat0 reports

No chart: no month has 5 or more reports.

Horse0 reports

No chart: no month has 5 or more reports.

Other or not given0 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 n-butyl chloride, by the year in which FDA received them and by species
Year	Dog	Cat	Other or not given	All species
2000	1	0	0	1
1998	0	1	0	1
1996	6	3	0	9
1995	3	1	0	4
1994	1	7	0	8
1993	1	0	0	1
1992	4	0	1	5
1991	3	0	1	4
1989	1	1	0	2
1988	4	3	0	7
1987	0	1	0	1

2000 has the reports that FDA received through Mar 2000. Download the years (CSV)

What the reports record

Outcome at the time of the report

Recovered/Normal0%0
Recovered with Sequela[recovered, with a lasting effect]0%0
Ongoing0%0
Died34.9%15
Euthanized0%0
Outcome Unknown0%0

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 43 reports that name n-butyl chloride.

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

Kind of report

Safety issue100%43
Lack of expected effectiveness0%0
Both safety and lack of expected effectiveness0%0
Manufacturing or product defect0%0
Other0%0

Show age, weight, breed and route

Age of the animal

Under 1 year30.2%13
1 to 3 years9.3%4
4 to 7 years2.3%1
8 to 11 years7%3
12 years and over2.3%1
Age not given48.8%21

Weight of the animal

Under 5 kg (11 lb)23.3%10
5 to 9.9 kg (11 to 22 lb)9.3%4
10 to 24.9 kg (22 to 55 lb)7%3
25 to 44.9 kg (55 to 99 lb)4.7%2
45 kg and over (99 lb and over)0%0
Weight not given55.8%24

Breed, where the report gives one breed

Domestic14%6
German Shepherd Dog7%3
Siamese4.7%2
Beagle4.7%2
Rottweiler4.7%2
Manx2.3%1
Bulldog2.3%1
Chow Chow2.3%1

A breed with many animals has many reports.

Route in the report

Oral93%40
Ophthalmic2.3%1

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.

Brand names

Happy Jack Worm
NBC Kaps Wormer

What the Green Book records give

Applications with an approval in force: 2
Approved species: Dogs
Dose forms: Capsule
Routes: Oral
Sale: OTC (over the counter)

The species, dose forms and routes are the words of the Green Book records for all the applications together. One product can have fewer. The label of a product gives its approved use.

Applications in the Green Book of 1 Oct 2026, pioneer applications (NADA) first
Brand name	Active ingredients	Sponsor	Approved species	Application
Happy Jack Worm Capsules	N-butyl Chloride	Happy Jack, Inc.	Dogs	NADA 046-746
NBC Kaps Wormer	N-butyl Chloride	Zoetis Inc.	Dogs	NADA 096-509
N-Butyl Chloride Canine Worming Caps.approval withdrawn	N-butyl Chloride	IMPAX Laboratories	Dogs	NADA 092-151
N-Butyl Chloride Capsulesapproval withdrawn	N-butyl Chloride	Mallinckrodt Veterinary, Inc.	Not in the list of major species	NADA 092-481

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.
Green Book record of NADA 046-746The FDA record of the application for Happy Jack Worm Capsules.
Green Book record of NADA 096-509The FDA record of the application for NBC Kaps Wormer.
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. N-butyl Chloride: adverse event reports that FDA received. https://petdrugreports.com/drug/n-butyl-chloride/ 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 section of this page lists the brand names with 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 no reports in the 12 months to March 2026. It received no 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 43 reports received from May 1987 to March 2000, 100% are about a safety issue only.