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Atropine Sulfate

Prescription

Anticholinergic / Antimuscarinic

Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team

Species

Dog, Cat

Brands

2 available

Interactions

2 documented

Formulations

Mechanism of action

Competitive antagonist at muscarinic acetylcholine receptors (M1, M2, M3), blocking parasympathetic effects: increases heart rate, reduces secretions, causes bronchodilation, pupil dilation (mydriasis), and GI smooth muscle relaxation. Crosses blood-brain barrier.

At a glance

Class

Anticholinergic / Antimuscarinic

Schedule

Prescription

Storage

Store at room temperature, protect from light

Dosing

🐕

Dog

Essential emergency and preanesthetic drug

Dose

0.02–0.04 mg/kg

Route

IV, IM, SQ

Frequency

Preanesthetic: once; bradycardia: repeat q3–5 min; OP toxicity: repeat until secretions dry

🐈

Cat

Preanesthetic anticholinergic, bradycardia treatment, and organophosphate antido

Dose

0.02–0.04 mg/kg

Route

IV, IM, SQ

Frequency

Per indication

Educational reference only

This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Formulations

💊

Other — 4

Strength

—

Strength

—

Strength

—

Strength

—

Storage

Store at room temperature, protect from light

Safety

Monitoring parameters

Heart ratePupillary response (mydriasis expected)Urine outputGI motility signs

Educational reference only

Interactions

Moderate — 1

Metoclopramide

moderate

Atropine (anticholinergic) antagonizes metoclopramide's prokinetic effect (which depends on cholinergic facilitation). Antiemetic D2 blockade by metoclopramide is not affected.

Management: Prokinetic effect is reduced, but antiemetic effect preserved. Avoid combining if prokinetic goal is primary.

Minor — 1

Pimobendan

minor

Atropine-induced tachycardia increases myocardial oxygen demand in patients with heart disease. Pimobendan already increases inotropy/chronotropy.

Management: Use atropine cautiously in cardiac patients on pimobendan. Glycopyrrolate (no CNS effects) may be preferred preanesthetic anticholinergic.

Educational reference only

Brands

Other markets

Atropine Sulfate Injection

AtroPen

FAQs

Frequently asked questions

›What is Atropine Sulfate?

Atropine Sulfate is a anticholinergic / antimuscarinic used in pets. Competitive antagonist at muscarinic acetylcholine receptors (M1, M2, M3), blocking parasympathetic effects: increases heart rate, reduces secretions, causes bronchodilation, pupil dilation (mydriasis), and GI smooth muscle relaxation. Crosses blood-brain barrier.

›What is Atropine Sulfate used for in pets?

Atropine Sulfate is used in veterinary medicine for: Essential emergency and preanesthetic drug; Preanesthetic anticholinergic, bradycardia treatment, and organophosphate antido.

›What is the Atropine Sulfate dose for dogs?

For dogs, Atropine Sulfate is typically dosed as follows — Essential emergency and preanesthetic drug: 0.02–0.04 mg/kg IV/IM/SQ Preanesthetic: once; bradycardia: repeat q3–5 min; OP toxicity: repeat until secretions dry. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›What is the Atropine Sulfate dose for cats?

For cats, Atropine Sulfate is typically dosed as follows — Preanesthetic anticholinergic, bradycardia treatment, and organophosphate antido: 0.02–0.04 mg/kg IV/IM/SQ Per indication. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›Does Atropine Sulfate need a prescription?

Yes. Atropine Sulfate is a prescription medication and should only be administered under veterinary supervision.

Educational reference only

References

The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.

Textbooks & handbooks — 5

Plumb's Veterinary Drug Handbook
Withrow & MacEwen's Small Animal Clinical Oncology
Merck Veterinary Manual
NRC Nutrient Requirements of Dogs and Cats
Veterinary Pharmacology and Therapeutics (Riviere & Papich)

Clinical guidelines & consensus — 4

ASPCA Animal Poison Control Center Guidelines
AAHA Diabetes Management Guidelines
ASPCA Poison Control Guidelines
RECOVER CPR Guidelines

Journals & peer-reviewed studies — 2

EPIC Study (J Vet Intern Med 2016)
JVIM FAT CAT Study

Regulatory & approvals — 1

CDSCO Veterinary Drug Approval Registry (1969–2026)

Databases — 1

Washington State University VCPL MDR1 Database