Pilocarpine

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Pilocarpine

By: PetPlace Staff

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Overview

Glaucoma is a potentially devastating eye disease, caused by the buildup of abnormally high pressure in the eye. In the normal eye, watery fluid (called aqueous humor) is produced within the eye and drains continuously from the eye. Pressure within the eye builds up if this fluid does not drain properly, and this pressure can damage the optic nerve, leading to vision loss.

Pilocarpine is one of a number of topical agents used to treat glaucoma. It belongs to a class of drugs known as cholinergic agents and is derived from the Pilocarpus shrub of South America.

The drug acts on the parasympathetic nervous system.

The drug works by mimicking the effects of acetylcholine.

Pilocarpine stimulates smooth muscles of the iris and ciliary body, resulting in pupil constriction and other changes that help in the removal of aqueous humor from the eye.

Pilocarpine is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.

This drug is not approved for use in animals by the Food and Drug Administration, but it is prescribed legally by veterinarians as an extra-label drug.

Brand Names and Other Names

This drug is registered for use in humans only.

Human formulations: Isopto® Carpine ophthalmic solution (Alcon), Akarpine® (Akorn), Pilocarpine sterile ophthalmic solution® (Medical Ophthalmics), Pilocarpine HCl sterile ophthalmic solution® (Bausch & Lomb), Pilocar® (CIBA Vision), and various generic preparations

Veterinary formulations: None

Uses of Pilocarpine

Pilocarpine is used to treat primary glaucoma in non-inflamed eyes in dogs and cats.

It is occasionally used as a miotic (pupil constrictor) to make the pupil opening small in order to prevent the lens of the eye from dislocating, to test the function of the iris sphincter, and to treat severe pupil dilation associated with dysautonomia.

Precautions and Side Effects

While generally safe and effective when prescribed by a veterinarian, pilocarpine can potentially cause side effects in some animals.

Pilocarpine should not be used in animals with known hypersensitivity or allergy to the drug.

Ophthalmic solutions of pilocarpine are very acidic, and topical application frequently causes pain or stinging and redness of the eyes. Salivation may occur as well, if the drug drains down the tear duct passage ways into the nose or mouth.

More severe side effects may occur at higher concentrations or with the prolonged release form of the drug (Pilocarpine Ocusert®). These side effects include salivation, vomiting, diarrhea, muscle tremors, bradycardia and hypotension.

Pilocarpine may interact with other medications. Consult your veterinarian to determine if other drugs your pet is receiving could interact with pilocarpine.

How Pilocarpine Is Supplied

Pilocarpine is available as 0.25%, 0.5%, 1%, 2%, 3%, 4%, 6%, 8% solutions in 15ml and 30 ml bottles.

Individual dropperettes containing 1%, 2% and 4% pilocarpine are also available.

Dosing Information

Medication should never be administered without first consulting your veterinarian.

For treating primary glaucoma in dogs, 2% pilocarpine is initially administered 2 to 3 times daily. If pressure does not decrease, 3% or 4% pilocarpine may be tried twice daily.

For treating primary glaucoma in cats, the 1% solution is used twice daily in order to avoid systemic side effects.

When used in pharmacologic testing, 1 drop of 0.1% pilocarpine is applied to the dilated eye.

To induce miosis (constriction of the pupil) in the case of a loose lens, 2% to 4% pilocarpine can be tried 2 to 3 times per day in the dog. The drug is usually used for this purpose only in instances where the eye and/or the dog are not candidates for surgical removal of the loose lens.

For treating severe dilation associated with dysautonomia in cats, one drop of 0.5% - 1% pilocarpine is applied to the eyes as needed, to a maximum of 4 times daily. To stimulate tear secretion, one drop of 1% pilocarpine per 5 to 10 pounds body weight is given orally per day and divided into multiple doses. Withdrawal of the drug is indicated with any sign of systemic side effects.

The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Glaucoma medications must be giving consistently and on a reliable time schedule. Even if your pet feels better, glaucoma medications should not be stopped unless your veterinarian specifically instructs you to do so.