Drug profile

The FDA adverse-event record for Melarsomine Dihydrochloride

9,771 FDA reports name Melarsomine Dihydrochloride, a high-volume drug in the CVM extract. Species, reactions, and outcomes follow.

#27 of 2,679
by report volume (all drugs)
9,771
adverse-event reports
3.9%
death-coded share
Dog
most-reported species

Corpus placement

According to the FDA Center for Veterinary Medicine openFDA adverse-event extract, Melarsomine Dihydrochloride ranks #27 of 2679 by total reports (9,771) and #856 of 1130 by death-coded share (3.9%). National dual: Milbemycin Oxime + Spinosad is #1 of 2679 drugs by total adverse-event reports (149,624) at death-coded-share rank 965 of 1130 drugs with at least 50 reports (2.3%); separately, Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) is #1 highest death-coded share at 97.8% (report rank #821).

149,624
Milbemycin Oxime + Spinosad reports (#1)
97.8%
Atlantic Salmon Transgenic Whole (Opafp-Ghc2 Rdna Construct Inserted Into The A-Locus In The Eo-1A Lineage) death share (#1)
#27
This drug, reports of 2679
#856
This drug, death share of 1130

Report volume reflects how common a breed or drug is and how often owners and vets file — not actual risk. Death-coded share ranks are limited to entries with enough reports to be meaningful. The two maps do not agree at #1.

Release-over-release change

What changed in the latest FDA data snapshot

PlainBreed reconstructed the prior snapshot from dated openFDA partitions through 2025 Q4, then compared it with the 2026-07-27 openFDA export. Melarsomine Dihydrochloride has 9,771 reports now versus 9,631 in that prior snapshot: 140 more (1.5%).

Report change
+140
Death-coded reports
+3
Death-coded share
−0.0 pts

This compares reported-event counts in two source snapshots. It does not establish a change in real-world risk, product safety, or disease incidence.

Subscribe to Melarsomine Dihydrochloride changes

Signature read: 9,771 reports place Melarsomine Dihydrochloride in the upper third of FDA AER volume (#27 of 2,679).

Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
9,771
Total Reports
383
Deaths Reported
3.9%
Death-coded share of reports

Active Ingredients

Melarsomine Dihydrochloride

Administration Routes

IntramuscularUnknownSubcutaneousParenteralOralOphthalmicIntravenousOtherTopicalIntradermal

Species Affected

Dog 9,519
Unknown 204
Human 44
Cat 4

Most Affected Breeds

Retriever - Labrador 1,386
Crossbred Canine/dog 1,161
Shepherd Dog - German 590
Terrier - Bull - American Pit 467
Dog (unknown) 466
Beagle 427
Chihuahua 397
Boxer (German Boxer) 306
Pit Bull 289
Unknown 257

Most Reported Reactions

Lack of efficacy (endoparasite) - heartworm 2,363
Vomiting 1,088
INEFFECTIVE, HEARTWORM ADULTS 1,087
Injection site swelling 878
Injection site pain 536
Injection site lump 524
Lethargy (see also Central nervous system depression in 'Neurological') 524
Diarrhoea 517
Pain NOS 498
Panting 423
Elevated alanine aminotransferase (ALT) 359
Anorexia 316

Outcome Breakdown

Ongoing
4,434 (55.8%)
Outcome Unknown
1,993 (25.1%)
Recovered/Normal
905 (11.4%)
Died
287 (3.6%)
Recovered with Sequela
234 (2.9%)
Euthanized
97 (1.2%)

Melarsomine Dihydrochloride: low death-coded share in the FDA AER row

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.

High-volume nationwide drug peers

Two openFDA-derived peer sets for Melarsomine Dihydrochloride, both floored at ≥50 reports so the neighborhoods stay in the advertised mass.

Similar report volume

Nearest other drugs by FDA report count (9,771 here).

What to do with this drug

  • Compare Melarsomine Dihydrochloride's report volume and death-coded share against similar drugs nationwide. See similar drugs
  • Read how death-coded share differs from a mortality rate before drawing conclusions. Understanding adverse events
  • Browse the full drug directory to compare report counts across products. All drugs

A report does not prove a drug caused the reaction; consult a veterinarian before acting on this data.

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

openFDA Animal & Veterinary Adverse Events (FDA CVM) for Melarsomine Dihydrochloride (#27 of 2,679 by report volume); death-coded 3.9%. PlainBreed drug row · report volume stamp 9,771 · vintage 2025.

Informational only. FDA adverse-event reports are voluntary and do not prove causation; consult a veterinarian before acting on them. Verify with FDA CVM →