Pilocarpine

Pilocarpine is used across two very different forms — eye drops and oral tablets — for distinct medical conditions.

• Pilocarpine Hydrochloride Ophthalmic solution (eye drops) lowers elevated pressure inside the eye in people with open-angle glaucoma or ocular hypertension
• Pilocarpine Hydrochloride Ophthalmic solution (eye drops) is used to manage acute angle-closure glaucoma
• Pilocarpine Hydrochloride Ophthalmic solution (eye drops) prevents pressure spikes after laser eye surgery
• Pilocarpine Hydrochloride Ophthalmic solution (eye drops) is used to induce miosis (pupil constriction) when clinically needed
• Vuity eye drops are approved to treat presbyopia (age-related loss of near-vision focus) in adults
• Qlosi eye drops are approved to treat presbyopia in adults
• Pilocarpine Hydrochloride Ophthalmic solution 1.25% is approved to treat presbyopia in adults
• Pilocarpine hydrochloride tablets (including Salagen) treat dry mouth from salivary gland damage caused by radiation therapy for head and neck cancer
• Pilocarpine hydrochloride tablets (including Salagen) treat dry mouth in people with Sjögren's syndrome

Pilocarpine is a cholinergic agent — it binds to and activates muscarinic receptors, which are the body's chemical on-switches for secretion and smooth muscle activity. In the eye, activating these receptors constricts the pupil and improves the drainage of fluid, which lowers pressure inside the eye; it also helps the eye's lens adjust focus, which is useful in presbyopia. When taken by mouth, it stimulates the salivary glands directly, increasing the amount of saliva produced and relieving the discomfort of a dry mouth.

Because these receptors are found throughout the body, pilocarpine can also stimulate sweat glands, the digestive tract, and the airways — which is why side effects like sweating, nausea, and breathing changes can occur.

Pilocarpine comes in two very different forms with different schedules, so the route matters a lot.

• Eye drops for glaucoma: typically one drop in the eye(s) up to four times daily — frequency depends on how severe the pressure elevation is
• Eye drops for presbyopia (Vuity): one drop in each eye once daily, with an optional second dose 3–6 hours later
• Eye drops for presbyopia (Qlosi): one drop in each eye, which may be repeated once after 2–3 hours, up to twice daily
• Tablets for dry mouth: taken multiple times a day — your prescriber will set the schedule; high-fat meals can slow how quickly the tablet is absorbed

If you have moderate liver disease, the oral tablet dose will start lower. Severe liver impairment is a reason to avoid the tablets altogether. Always follow your prescriber's exact directions.

The most common side effects are linked to pilocarpine's action on the body's secretory glands and smooth muscles.

• Sweating (very common with oral tablets, especially at higher doses)
• Nausea
• Runny nose
• Diarrhea
• Chills
• Blurred vision or reduced night vision (eye drops)
• Reduced depth perception (eye drops)

Contact your doctor or seek urgent care if you develop wheezing or difficulty breathing, a very fast or slow heartbeat, or any signs of fluid in the lungs such as sudden shortness of breath — these are signs of a more serious reaction that needs prompt attention.

• Heart disease: Pilocarpine can cause unpredictable changes in blood pressure and heart rate — both increases and decreases have been reported. People with significant cardiovascular disease need close monitoring.
• Lung and airway problems: Pilocarpine tightens bronchial smooth muscle and increases airway secretions. It is contraindicated in uncontrolled asthma and should be used very carefully in people with controlled asthma, chronic bronchitis, or COPD.
• Vision impairment from eye drops: The drops can blur vision and reduce depth perception, especially at night or in low light. Do not drive or operate machinery in reduced lighting if your vision is affected.
• Pulmonary edema (fluid in the lungs): This has been reported as a serious complication when high doses of pilocarpine eye drops are used for acute angle-closure glaucoma.
• Liver disease: Moderate liver impairment slows the body's clearance of oral pilocarpine, increasing exposure. A lower starting dose is required. Severe liver impairment: tablets are not recommended.

Pilocarpine can interact with several types of medications — tell your doctor and pharmacist about everything you take.

• Beta-blockers (e.g., metoprolol, atenolol): combining with pilocarpine may cause heart conduction problems or rhythm disturbances
• Other parasympathomimetic drugs (drugs that mimic the same nerve signals): effects add together and increase the chance of side effects like sweating, nausea, and slow heart rate
• Anticholinergic drugs (e.g., atropine, inhaled ipratropium): pilocarpine works against these, and may reduce how well they work — this is important if you rely on them for conditions like COPD

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

• Do not take pilocarpine if you have uncontrolled asthma — it can dangerously tighten the airways
• Do not take it if you are allergic to pilocarpine
• Oral pilocarpine tablets should not be used when miosis (pupil constriction) would be harmful — for example, in acute iritis or narrow-angle glaucoma
• Tell your doctor if you have heart disease — pilocarpine can affect heart rate and blood pressure
• Tell your doctor if you have controlled asthma, chronic bronchitis, or COPD — use is possible but requires close supervision
• Tell your doctor if you have liver problems: moderate impairment requires a dose reduction; severe impairment means tablets are not recommended
• Older adults, especially elderly women, may absorb more of the oral tablet — discuss dosing with your prescriber
• Kidney disease does not appear to significantly change how the body handles oral pilocarpine, based on available data

A pilocarpine overdose is a medical emergency. Fatal overdoses have been reported in hospitalized patients who received very large amounts. If you suspect an overdose, call emergency services or poison control immediately.

Medical treatment for overdose typically involves atropine (given by injection) to counteract pilocarpine's effects, along with supportive care to maintain breathing and circulation. Epinephrine may also be used if there is severe cardiovascular collapse or severe bronchospasm.

Pilocarpine stimulates the body's exocrine glands — including the salivary, sweat, lacrimal (tear), and digestive glands — causing them to increase secretions. In the eye, it constricts the pupil (miosis), causes the focusing muscle to tighten (spasm of accommodation), and lowers intraocular pressure after an initial brief rise. It also increases smooth muscle tone in the digestive tract, urinary tract, and airways, and can produce complex and sometimes unpredictable effects on the cardiovascular system, including both drops and rises in blood pressure, and both slowing and speeding of the heart rate.

When taken by mouth, pilocarpine is absorbed relatively quickly — saliva flow increases within about 20 minutes and peaks around 1 hour, lasting 3 to 5 hours. The drug is broken down at nerve junctions and in the blood, and is excreted through the urine. It has a short half-life (the time for blood levels to drop by half), typically less than 1.5 hours at standard doses. People with moderate liver disease clear the drug more slowly, roughly doubling their exposure — which is why a lower dose is used. Kidney disease does not significantly change how the drug behaves. Elderly women tend to have higher blood levels than elderly men or younger adults at the same dose.

Store at 20 o to 25 o C (68 o to 77 o F) .