Atropine for Dogs

Written By Kim Rain
Published: 03/22/2021Updated: 03/23/2021
Atropine for Dogs

Atropine for dogs is an anticholinergic medication that is primarily used in dogs for pupil dilation, to treat eye conditions such as injury, corneal ulcers, corneal disease, uveitis, and glaucoma, and after cataract surgery. This medication works by relaxing the eye muscles, which in turn, reduces localized pain. It can also be used with anesthesia to counter its non-desirable effects, including a slow heart rate and drooling, and in emergency CPR. Atropine is a significant antidote in cases of toxic poisoning from mushrooms, plants, several toad species, pesticides and insecticides, and can also be prescribed for nausea, diarrhea and breathing problems.


Atropine Sulphate is only available by prescription. Most commonly, atropine is formulated as a 1% optic solution and ointment, and through veterinarians as an injection. Prices can vary, but on average, a 5ml bottle of optic solution costs about $45, and a 15ml bottle about $130. Ointments come in a 3.5gm size for about $20.


Atropine for dogs is most commonly applied as a 1% or 2% topical solution or ointment directly into the eyes. Administration for toxicity, CPR, and with anesthesia is given only by veterinarians, and is generally by injection. While each dog and situation is unique and may require different dosage amounts, a general dosing guideline for eye conditions is:

  • For optic solutions: 1 to 3 drops in eye, 1 to 3 times daily as prescribed

Dosage instructions

Atropine sulphate is prescribed to dog owners as an optic solution or ointment to be given several times a day, depending on the condition being treated. When administering, be careful not to touch the tip of the dropper directly to the eye, and keep out of your dog’s mouth as the bitter taste can induce drooling. Be sure to completely administer the entire prescription as directed by your veterinarian.

Since this medication dilates the pupils, keep your dog out of sunlight or other bright light while medicated. Effects of atropine can last for several days, up to 7 in some dogs. 


To measure the efficacy of atropine in treating a decreased heart rate, or bradycardia, due to anesthesia, one study administered atropine after anesthesia in 10 dogs. Researchers found that atropine not only reversed the bradycardia, but also improved other cardiovascular parameters that were measured, including heart output and oxygen transport. In another study comparing various types of anesthesia medications, it was found that the administration of atropine before anesthesia had positive effects on the heart rate and breathing.

While looking at how atropine affects the eye, researchers measured pupil diameters in treated and untreated dogs. Findings showed that atropine applied both topically into the eye and by intramuscular injection increased pupil dilation.

Side effects of Atropine

The most common side effect from atropine for dogs results from its bitter taste, which results in drooling. Photosensitivity can also be common. The side effects of atropine use include:

  • Drooling
  • Pawing at mouth
  • Dry mouth
  • Photophobia, or light sensitivity
  • Decreased tear production
  • Blurred vision
  • Drowsiness
  • Constipation
  • Vomiting
  • Increased body temperature
  • Increased thirst
  • Inability to urinate
  • Lens luxation
  • Changes in heart rate and rhythm

Too much atropine can cause many of these symptoms, so always consult with your veterinarian if you notice any signs of toxicity past drooling and photophobia, especially when concerning urination, temperature and heart rate.


While atropine for dogs can be used to treat glaucoma, it can worsen the condition in dogs with primary glaucoma or those predisposed to glaucoma, and should be avoided. This medication should not be used in dogs with reflex bradycardia that is secondary to hypertension, dogs with impaired function in their kidneys, liver or heart, those with rapid heart rates, or in cases of lens luxation. 

Drug interactions

Atropine Sulphate (Atroject, Atropine LA) may interact with the following medications:

  • Anti-parasitic drug (amitraz)
  • Antihistamines
  • Benzodiazepines (diazepam)
  • Antiarrhythmic agent (Disopyramide phosphate, procainamide, quinidine)
  • Corticosteroids (hydrocortisone or dexamethasone)
  • Opiate pain medication (meperidine)
  • Metoclopramide
  • Antibiotic (nitrofurantoin)
  • Phenothiazines
  • Anticonvulsant (primidone)
  • Sympathomimetics
  • Thiazide diuretics

As with any medicinal treatment, be sure to tell your veterinarian about any other medications, vitamins or supplements your dog may be taking before starting therapy. 

Allergic reactions and sensitivity

Some dogs may be allergic or hypersensitive to atropine and should not take this medication. Signs of an allergic reaction to medication can include hives, difficulty breathing, swelling, and shock, and should be seen by a veterinarian immediately. 

Frequently asked questions

Do I need a prescription for Atropine Sulphate?

Atropine for dogs is only available through a prescription from your veterinarian.

What do I do if I skip a dose?

If you miss a dose of atropine, give it as soon as you remember. If, however, it is within a few hours of the regularly scheduled dose, then give that dose on time and skip the missed dose. Never give your dog a double dose of atropine.

How do I store this medicine?

Atropine should be stored out of reach of children and pets, and in a tight, light-proof container, or away from light.

What should I do in case of emergency?

Signs of an accidental overdose can include vomiting, drooling, disorientation, lethargy, and loss of appetite. If you think your dog has overdosed on atropine, or is experiencing signs of an allergic reaction, seek immediate veterinary attention.

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