What to Know About Ophthalmic Pilocarpine

Drug Approved to Treat Glaucoma and Other Eye Conditions

Pilocarpine solution reduces eye pressure. It can be used to treat glaucoma, a disease in which fluid builds up in the front part of the eye, increasing eye pressure. This is something that can lead to damage of the ophthalmic nerve.

Pilocarpine drops can also help with ocular hypertension in which there is a rise in eye pressure from aqueous fluid buildup. In addition, it can help lower high eye pressure after laser eye surgery. Also, pilocarpine can cause the pupil to constrict.

It is available as an eyedrop, with brand names such as:

  • Isopto Carpine
  • Minims Pilocarpine (Canada)
  • Pilocar

It is also available in gel form as Pilocarpine HS and as a pilocarpine solution insert known as Ocusert Pilo.

Man taking eye drops such as pilocarpine
Jovanmandic / iStock / Getty Images

Uses

Administering eye drops is usually the first line of defense in treating glaucoma, with the goal towards lowering increased intraocular pressure. Pilocarpine is a medication with a long track record. It is a topical drop that was developed more than 50 years ago to reduce elevated intraocular pressure.

This is made from Jaborandi leaves (Pilocarpus microphyllus), which has an anti-cholinergic effect causing muscle contraction. Pilocarpine can be used to lower eye pressure in either adults or children with open-angle glaucoma or ocular hypertension.

With open-angle glaucoma, pressure in the eye is high due to the slow clogging of drainage canal usually building over years. However, the angle found where the iris and cornea meet, remains open, as is normally the case.

Pilocarpine can also be used to manage pressure in acute-angle closure glaucoma. With this type of glaucoma, the angle is blocked abruptly stopping up the drainage canals and causing a rapid rise in pressure. Pilocarpine is also approved for the induction of miosis in which the pupil tightly constricts.

Before Taking

In evaluating whether you may need a pressure-lowering drop such as pilocarpine, your doctor will examine the eye, checking for increased pressure, and also look closely at the retina and other structures for signs of glaucoma such as visual field loss and optic nerve damage.

If glaucoma is diagnosed, then, based on how severe this is, the doctor will develop a treatment plan for you.

If you have been prescribed this medication, you should be sure to alert the doctor of any prior reaction to pilocarpine, or of any signs of allergy that may develop, such as swelling of the eye. Also, it’s important that you discuss any other allergies to drugs or food which have occurred.

Precautions

Since pilocarpine constricts the pupil making it harder for light to get in, this should not be used if you will be driving at night or operating other equipment in dim lighting.

Also, those with pre-existing retinal disease, in particular, should be aware that while rare, there is the risk of retinal detachment. So, before beginning therapy with pilocarpine, all patients are advised to undergo a thorough retinal examination.

If you wear contact lenses, be sure to remove these before putting pilocarpine drops in your eyes and then wait 10 minutes after instillation before reinserting these.

It is currently not known whether pilocarpine drops can cause harm to a developing fetus or whether the drug can be excreted by people who are breastfeeding, so other options should also be considered.

Contraindications

If you have hypersensitivity to any of the components here, use of pilocarpine should be avoided. Those with other medical conditions, such as asthma or other eye-related issues should also alert the doctor about this. If you have iritis, you should avoid this medication.

Caution is also necessary in pediatric congenital glaucoma cases in which pilocarpine drops are used to control intraocular pressure since this has been known to actually cause an increase in eye pressure for some children.

Pilocarpine is also not recommended for those children with glaucoma arising from either uveitis or anterior segment dysgeneses, in which the structures at the front of the eye have not developed normally.

Other Ophthalmic Anticholinergics

Pilocarpine is not the only anticholinergic agent for the eye. Other common anticholinergic agents in this class used in the eye include:

  • Acetylcholine (Miochol-E), approved for inducing pupil constriction
  • Carbachol (Isopto Carbachol; Miostat), also labeled for the treatment of glaucoma and inducing pupil constriction
  • Echothiophate Iodide (Phospholine Iodide), approved for the treatment of accommodative esotropia (crossed eyes)

It’s important to note that these may be used for different applications than the pilocarpine.

Dosage

Pilocarpine drops are available in 1%, 2%, and 4% concentrations. In those with open-angle glaucoma or ocular hypertension, drops are given up to four times a day.

In children under the age of 2, 1 drop of 1% pilocarpine should be placed in the eye up to 3 times daily. Those over the age of 2 can be dosed the same way as adults.

In cases of acute angle-closure glaucoma, a patient may use the 1% to 2% dosage up to three times a day.

When pilocarpine is used in conjunction with laser treatment for either iridoplasty, in which the laser is used to widen the angle in the anterior chamber, or iridotomy in which a small hole is made in the iris to allow for fluid outflow, a drop of 4% pilocarpine should be used prior to the procedure.

For those awaiting an iridotomy, who have already undergone an iridoplasty, 1% pilocarpine drops should be used four times a day.

The eye insert Ocusert Pilo system is able to elute pilocarpine to treat glaucoma for up to seven days, instead of having to put in drops four times a day.

Storage

Pilocarpine drops should be stored at room temperature, between 59 and 77 degrees Fahrenheit, with care taken to protect these from excessive heat or freezing. The gel formulation can be stored at between 36 and 80 degrees Fahrenheit. This should be protected against excessive heat as well as freezing.

How to Take

Before handling the pilocarpine drop bottle, your hands should first be washed. Your head should be then tilted back. Use your finger to pull down the lower lid down, creating room for the drop.

After this is instilled, close your eye for one to two minutes while applying pressure on the inner corner of the eye to help ensure the medication is properly absorbed. Hands should then be washed and the bottle cap closed, taking care not to contaminate the tip.

With Pilocarpine HS ophthalmic gel, with clean hands and your head tilted back, your middle finger is used to pull down the lower lid, pulling this away from the face. You can then squeeze a thin 1/2-inch ribbon of the gel in the area.

The eye is then closed for one to two minutes to allow the medication to properly absorb and a clean tissue used to wipe away any excess medication.

With the Ocusert Pilo system which elutes pilocarpine throughout the week, closely follow the directions for insertion that are provided to correctly place the unit. This technique should initially be practiced with a doctor’s guidance. If there is any damage to the Ocusert Pilo system, this should be immediately removed and replaced by a new one.

Side Effects

Pilocarpine not unlike other medications can have some common ocular side effects such as:

  • Tearing
  • Burning
  • Blurred vision at distance
  • Headache/brow ache
  • Corneal inflammation
  • Induction of nearsightedness
  • Trouble seeing in dim light, particularly for older individuals and those with cataracts
  • Redness of the eye
  • Pain

Also, other systemic reactions can occasionally occur include sweating and gastrointestinal overactivity.

Warnings and Interactions

While it is rare for those using this topical medication to have systemic issues, these can happen. Signs of a possible overdose of pilocarpine include:

  • Sweating
  • Salivation
  • Nausea
  • A reduction in pulse rate
  • A blood pressure decrease

Pilocarpine can be readily used in combination with other types of glaucoma drops such as beta blockers, carbonic anhydrase inhibitors, sympathomimetics, or hyperosmotic agents. However, different types of drops should be placed in the eye at least five minutes apart.

One medication, however, pilocarpine should not be taken with is the chemotherapeutic agent, Tegafur. Be sure to alert the doctor if you are taking this medication, so other options can be tried.

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Article Sources
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