Diphenhydramine
2,668 adverse event reports submitted to the FDA
Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
2,668
Total Reports
211
Deaths Reported
790.0%
Death Rate
Active Ingredients
Diphenhydramine
Administration Routes
UnknownOralIntramuscularParenteralSubcutaneousIntravenousTopicalOtherNasalTransdermal
Species Affected
Dog 2,475
Cat 176
Human 14
Unknown 1
Horse 1
Ferret 1
Most Affected Breeds
Retriever - Labrador 245
Crossbred Canine/dog 129
Chihuahua 113
Domestic Shorthair 111
Pit Bull 105
Boxer (German Boxer) 100
Terrier - Yorkshire 90
Shih Tzu 84
Pug 79
Bulldog - French 77
Most Reported Reactions
Vomiting 582
Emesis 339
Lethargy (see also Central nervous system depression in 'Neurological') 332
Diarrhoea 322
Lethargy (see also Central nervous system depression in Neurological) 228
Not eating 184
Lack of efficacy - NOS 183
Injection site swelling 178
Panting 155
Lack of efficacy (ectoparasite) - flea 153
Decreased appetite 148
Anaphylaxis 145
Outcome Breakdown
Recovered/Normal
1,002 (37.6%)
Outcome Unknown
794 (29.8%)
Ongoing
562 (21.1%)
Died
106 (4.0%)
Euthanized
105 (3.9%)
Recovered with Sequela
97 (3.6%)
Source: FDA Center for Veterinary Medicine — Adverse Event Reports. Data reflects voluntary submissions and may not represent actual incidence rates.