● ANSWER
Sourced & dated

What is the epinephrine dose for anaphylaxis in dogs and cats?

Vetinuity's anaphylaxis table: epinephrine 0.01 mg/kg IM (0.01 mL/kg of 1 mg/mL), repeated every 5 to 15 minutes, then a 0.05 mcg/kg/min CRI if shock persists, with fluids.

Updated

By Vetinuity, founded by Brian Toncray, DVM, emergency veterinarian

● VETINUITY ANAPHYLAXIS DOSE CALCULATOR

Vetinuity anaphylaxis dose calculator

Epinephrine is the only first-line drug. Antihistamines and steroids come after it, never instead of it.

DrugDoseRoutePatient doseVolume
Epinephrine 1 mg/mL mg/kg IM, repeat q5-15 min
Epinephrine CRI mcg/kg IV CRI, per minute, titrate to BP
Isotonic crystalloid bolus mL/kg IV over 15 min
Isotonic crystalloid bolus mL/kg IV over 15 min
Diphenhydramine mg/kg IM or slow IV
Famotidine mg/kg IV slowly q12h
● WHAT'S DOCUMENTED

Vetinuity’s anaphylaxis table: give epinephrine 0.01 mg/kg IM (0.01 mL/kg of the 1 mg/mL vial) to dogs and cats, repeat every 5 to 15 minutes as needed, start an epinephrine CRI at 0.05 mcg/kg/min titrated upward if hypotension persists, and support with crystalloid boluses of 10 to 20 mL/kg; diphenhydramine 1 mg/kg and famotidine 1 mg/kg follow as second-line drugs. The Vetinuity anaphylaxis dose calculator above converts every dose to millilitres for the patient’s weight. Emergency veterinarian Brian Toncray, DVM, built Vetinuity, a clinical assistant, so that numbers like these are a tap away during a reaction.

Recognizing it

Dogs often present with acute vomiting, diarrhea and collapse within minutes of an insect sting, vaccine or drug, sometimes with hives or facial swelling but often without. Cats show respiratory signs, drooling, vomiting and collapse. Hypotension, tachycardia and hemoconcentration are common; a rising ALT the next day reflects the hepatic involvement typical in dogs. Point-of-care ultrasound showing gallbladder wall edema in a collapsed dog strengthens the diagnosis.

Step by step

  1. Epinephrine IM at once; do not wait for IV access.
  2. Oxygen, IV catheter, crystalloid bolus, then reassess pressure and lactate.
  3. Repeat IM epinephrine or start the CRI if blood pressure stays low.
  4. Diphenhydramine and famotidine for skin and gut signs.
  5. Observe at least 12 to 24 hours; biphasic reactions occur.

After the reaction

Glucocorticoids such as dexamethasone are often given but act over hours and have not been shown to prevent the biphasic phase; never let them delay epinephrine. Record the trigger in the record, flag the vaccine or drug, and premedicate or avoid it next time. Severe cases can develop coagulopathy and need plasma.

Related: diphenhydramine doses, famotidine doses and shock fluid boluses.

● SOURCES
  1. 1. Turner K, Boyd C, Stander N, et al. Clinical characteristics of two-hundred thirty-two dogs (2006-2018) treated for suspected anaphylaxis in Perth, Western Australia. Aust Vet J. 2021;99(12):505-512. PMID 34541658. Abstract. Checked 2026-10-26.
  2. 2. Burkitt-Creedon JM, Boller M, Fletcher DJ, et al. 2024 RECOVER Guidelines: Updated treatment recommendations for CPR in dogs and cats. J Vet Emerg Crit Care (San Antonio). 2024;34 Suppl 1:104-123. PMID 38924627. Drug dosing table, epinephrine. Checked 2026-10-26.
● RELATED ANSWERS
  • Diphenhydramine (Benadryl) Dose for Dogs and Cats

    Diphenhydramine is dosed at 2 mg/kg IM or SC (or 2-4 mg/kg PO q8-12h) in dogs and 1-2 mg/kg IM or PO q8-12h in cats, using plain products without decongestants or xylitol.

  • Famotidine (Pepcid) Dose for Dogs and Cats

    Famotidine is dosed at 0.5-1 mg/kg PO or slow IV every 12 hours in dogs and cats; twice-daily dosing matters because once-daily famotidine barely moves gastric pH.

  • Shock Fluid Bolus Volumes for Dogs and Cats

    Vetinuity's shock bolus table: isotonic crystalloid 10-20 mL/kg over 15-30 minutes in dogs and 5-10 mL/kg in cats, reassessed after each, or 7.5% hypertonic saline at 3-5 mL/kg in dogs.

  • RECOVER CPR Guidelines for Dogs

    RECOVER CPR guidelines for dogs: compression rate and depth, ventilation, drug therapy, monitoring, post-arrest care, and what the 2024 update changed.

  • Blood Transfusion Volume for Dogs and Cats

    Vetinuity's transfusion table: volume (mL) = weight x blood volume (90 mL/kg dog, 60 mL/kg cat) x (target PCV - patient PCV) / donor PCV; pRBC 10-15 mL/kg raises PCV about 10%.

● FAQ

IM or IV epinephrine?

IM into a large muscle for most patients. Reserve IV epinephrine for collapse or cardiac arrest, at the RECOVER low dose of 0.01 mg/kg, because IV boluses can cause arrhythmias.

What is the gallbladder halo sign?

A double-rimmed, edematous gallbladder wall on abdominal ultrasound. In a dog with acute collapse, vomiting and no other cause, it supports anaphylaxis, because the canine liver and gut are the main shock organs.

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