By Lauren R. Forsythe, PharmD, MBA, DICVP; Rania Gollakner, BS, DVM, MPH

What is pilocarpine?

Pilocarpine (brand names: Isopto-Carpine®, Pilocar®, Ocu-carpine®, Ocusert Pilo®, Pilopine-HS®, Minims Pilocarpine®) is an eye medication used to treat neurogenic keratoconjunctivitis sicca (dry eye caused by a nerve problem). It can also be used to diagnose problems with cranial nerve III.

In the past, it has been used to treat primary glaucoma in dogs, but its use for this condition has typically been replaced by more effective medications.

Its use in dogs and cats to treat dry eye or glaucoma, or to diagnose cranial nerve lesions is “off label” or “extra-label”. Many drugs are commonly prescribed for off-label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.

How is pilocarpine given?

  • To treat neurogenic dry eye, pilocarpine is given by mouth, as a liquid solution, in food.
  • To treat primary glaucoma or to diagnose a lesion of cranial nerve III, pilocarpine is applied topically, directly to the eye. 
  • If using in the eye, administer this medication 5 minutes apart from all other eye medications. 
  • Do not touch the tip of the eye dropper to the eye or any other substance or surface .
  • Do not use this medication if the solution changes color, if particles are seen in the solution, or if the solution becomes cloudy.

Animal studies have not clearly established how quickly pilocarpine will take effect, but based on human studies, pilocarpine should begin to work quickly, within 1 to 2 hours.

What if I miss giving my pet the medication?

If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. However, if it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.

Are there any potential side effects?

When administered orally (by mouth), pilocarpine may cause the following side effects:

  • vomiting
  • diarrhea
  • increased salivation
  • increased urination
  • coughing 
  • pulmonary edema

When administered to the eye, the most common side effects is irritation at the site of application, which usually resolves after a few days. This irritation may include redness, squinting, and cloudiness in the eye.

Chronic use in the eye may cause irreversible constricted pupils.

The duration of pilocarpine’s effects is not well understood in animals. Based on human studies, pilocarpine is a short-acting medication and should stop working within 24 hours when given orally or as an eye drop. Effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Pilocarpine should NOT BE USED in:

  • pets that are allergic to it
  • dogs with glaucoma that has occurred due to uveitis or lens luxation

Pilocarpine should be USED WITH CAUTION in pregnant or nursing pets, as effects of this medication in these situations are unknown.

Are there any drug interactions I should be aware of?

There are no known drug interactions. Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is any monitoring needed with this medication?

  • Watch your pet closely for side effects, as this could indicate a toxicosis. 
  • Your veterinarian may monitor your pet to be sure that the medication is working by checking tear production, eye pressures, and the physical condition of the eye.

How do I store pilocarpine?

  • Store at a controlled room temperature (15°C-25°C or 59°F-77°F).
  • Protect from moisture, light, and freezing.
  • Do not use this medication if the solution changes color, if particles are seen in the solution, or if the solution becomes cloudy.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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