Table of Contents 16 sections Group Mechanism of Action Dose Rates Dog Cat Horse Pig Cattle Sheep Goat Indications Contraindications Interactions Adverse effects Toxicity Preparations
Atropine Atropine is used for clinically important vagally mediated bradycardia and for muscarinic signs of cholinesterase-inhibitor poisoning. It does not reverse nicotinic muscle weakness.
Antimuscarinic; parasympatholytic
Competitive blockade of muscarinic acetylcholine receptors increases sinus rate, decreases secretions and reduces smooth-muscle motility.
Dog Use / stage Dose Route Schedule Instructions Vagal bradycardia 0.02–0.04 mg/kg IV, IM, SC As needed Titrate to clinically important bradycardia and perfusion; monitor ECG. Organophosphate or carbamate poisoning 0.2–0.5 mg/kg IV, IM, SC As needed Titrate to respiratory secretions and other muscarinic signs. Does not reverse nicotinic paralysis.
Cat Use / stage Dose Route Schedule Instructions Vagal bradycardia 0.02–0.04 mg/kg IV, IM, SC As needed Titrate to clinically important bradycardia and perfusion; monitor ECG. Organophosphate or carbamate poisoning 0.2–0.5 mg/kg IV, IM, SC As needed Titrate to respiratory secretions and other muscarinic signs. Does not reverse nicotinic paralysis.
Horse Use / stage Dose Route Schedule Instructions Cholinesterase-inhibitor poisoning 0.02–0.04 mg/kg IM, SC As needed Monitor closely for GI stasis and colic. Equine asthma bronchoconstriction 0.022 mg/kg IV Once Single administration only; monitor heart rate and intestinal motility.
Pig Use / stage Dose Route Schedule Instructions Cholinesterase-inhibitor poisoning — Initial 0.1 mg/kg IV Once Initial component before the intramuscular component; titrate clinical response. Cholinesterase-inhibitor poisoning — Maintenance 0.4 mg/kg IM As needed After the initial intravenous component; repeat only according to muscarinic signs. Anesthetic antisialagogue 0.02 mg/kg IV Once Anesthetic antisialagogue 0.04 mg/kg IM Once
Cattle Use / stage Dose Route Schedule Instructions Cholinesterase-inhibitor poisoning — Initial 0.1 mg/kg IV Once Initial component before the intramuscular component; titrate clinical response. Cholinesterase-inhibitor poisoning — Maintenance 0.4 mg/kg IM As needed After the initial intravenous component; repeat only according to muscarinic signs. Anesthetic antisialagogue 0.02 mg/kg IV Once Anesthetic antisialagogue 0.04 mg/kg IM Once
Sheep Use / stage Dose Route Schedule Instructions Cholinesterase-inhibitor poisoning — Initial 0.1 mg/kg IV Once Initial component before the intramuscular component; titrate clinical response. Cholinesterase-inhibitor poisoning — Maintenance 0.4 mg/kg IM As needed After the initial intravenous component; repeat only according to muscarinic signs. Anesthetic antisialagogue 0.02 mg/kg IV Once Anesthetic antisialagogue 0.04 mg/kg IM Once
Goat Use / stage Dose Route Schedule Instructions Cholinesterase-inhibitor poisoning — Initial 0.1 mg/kg IV Once Initial component before the intramuscular component; titrate clinical response. Cholinesterase-inhibitor poisoning — Maintenance 0.4 mg/kg IM As needed After the initial intravenous component; repeat only according to muscarinic signs. Anesthetic antisialagogue 0.02 mg/kg IV Once Anesthetic antisialagogue 0.04 mg/kg IM Once
Hemodynamically important vagal bradycardia. Muscarinic manifestations of organophosphate or carbamate poisoning. Selected anesthetic adjunct use. A single dose may relieve bronchoconstriction in equine asthma, with close attention to gut motility. Glaucoma, intestinal ileus or gastroparesis. Tachyarrhythmia or clinically important tachycardia unless an overriding toxicologic indication exists. Repeated administration in horses increases the risk of GI stasis and colic. Obstructive uropathy or mechanical GI obstruction. Atropine may worsen hypertension and intestinal stasis during amitraz poisoning; it is not a substitute for reversing alpha-2 effects. Other antimuscarinic drugs increase tachycardia, retention and GI stasis. Opposes cholinergic/prokinetic effects, including part of metoclopramide activity. Do not mix with alkaline solutions. Tachycardia and increased myocardial oxygen demand. Dry mouth, constipation, ileus and urinary retention. Mydriasis and possible CNS excitation with excessive exposure. In cattle, appetite reduction and rumen stasis may persist beyond the immediate treatment period. Monitor ECG, blood pressure, secretions and gut motility. In cholinesterase-inhibitor poisoning, titrate to reversal of muscarinic respiratory signs rather than pupil size alone. In addition to ECG monitoring, reassess urination, defecation, appetite and secretions. Rabbits may metabolize atropine rapidly because of atropinesterase, making responses less predictable.
Preparation Form Strength Route Atropine sulfate injection 0.4 mg/mL Injection 0.4 mg / mL IV, IM, SC Atrovet injection 1 mg/mL Injection 1 mg / mL IM
