Drug profile

The FDA adverse-event record for Cyproheptadine Hcl

38 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Cyproheptadine Hcl. See the species affected, top reactions, and outcomes below.

38
adverse-event reports
39.5%
death-coded share
Cat
most-reported species
12
Lethargy (see also Central nervous system depression in 'Neurological') - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
38
Total Reports
15
Deaths Reported
39.5%
Death Rate

Active Ingredients

Cyproheptadine Hcl

Administration Routes

UnknownOral

Species Affected

Cat 31
Dog 7

Most Affected Breeds

Domestic Shorthair 20
Domestic Longhair 6
Maltese 2
Pinscher - Miniature 1
Domestic (unspecified) 1
Shepherd Dog - German 1
Mixed (Dog) 1
Beagle 1
Ragdoll 1
Maine Coon 1

Most Reported Reactions

Lethargy (see also Central nervous system depression in 'Neurological') 12
Weight loss 11
Behavioural disorder NOS 9
Anorexia 9
Anaemia NOS 9
Death by euthanasia 8
Death 7
Vomiting 7
Not eating 6
Ataxia 6
Fever 5
Decreased appetite 4

Outcome Breakdown

Ongoing
19 (50.0%)
Euthanized
8 (21.1%)
Died
7 (18.4%)
Recovered/Normal
4 (10.5%)

Cyproheptadine Hcl Adverse Event Insights

38 reports name Cyproheptadine Hcl; 15 recorded a death outcome (39.5% of reported events, not a population-level mortality rate). Active ingredient: Cyproheptadine Hcl. Administration routes: Unknown, Oral.

By species: Cat (31 reports), Dog (7 reports). By breed: Domestic Shorthair (20), Domestic Longhair (6), Maltese (2).

Leading clinical signs: Lethargy (see also Central nervous system depression in 'Neurological') (12), Weight loss (11), Behavioural disorder NOS (9), Anorexia (9). Outcome, 38 coded reports: Ongoing leads at 50.0%.

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.