Pilokarpin Karo Pharma (Pilocarpine)
Parasympathomimetic agent for reducing intraocular pressure in glaucoma
Pilokarpin Karo Pharma contains the active substance pilocarpine hydrochloride, a parasympathomimetic (cholinergic) agent used primarily as eye drops to lower intraocular pressure in patients with glaucoma (elevated eye pressure). Pilocarpine works by contracting the ciliary muscle, which opens the trabecular meshwork and facilitates the drainage of aqueous humor from the eye. It also causes miosis (constriction of the pupil). Pilocarpine is one of the oldest and most established medications for glaucoma management, with a well-documented safety profile spanning over a century of clinical use.
Quick Facts
Key Takeaways
- Pilokarpin Karo Pharma eye drops reduce intraocular pressure in glaucoma by facilitating aqueous humor drainage through the trabecular meshwork.
- The recommended dose is 1 drop in the affected eye(s) 2–3 times daily, using preservative-free single-dose units.
- Common side effects include temporary blurred vision, headache, myopia, and reduced night vision, especially at the start of treatment.
- The medication is considered safe during pregnancy and breastfeeding, but always consult your doctor before use.
- Do not use if you have inflammation of the iris (iritis or uveitis), and report any visual disturbances such as light flashes or sudden blurred vision immediately.
What Is Pilokarpin Karo Pharma and What Is It Used For?
Pilocarpine is a naturally occurring alkaloid originally derived from the leaves of the Pilocarpus plant species native to South America. It has been used in ophthalmology since the late 19th century, making it one of the oldest and most extensively studied medications for glaucoma. Despite the development of newer drug classes, pilocarpine remains an important therapeutic option, particularly in combination therapy or for specific types of glaucoma such as angle-closure glaucoma.
The primary mechanism of action of pilocarpine in the eye involves stimulating muscarinic receptors (specifically M3 receptors) in the ciliary muscle and iris sphincter muscle. When the ciliary muscle contracts, it pulls on the scleral spur, which opens the trabecular meshwork — the eye's primary drainage pathway for aqueous humor. This facilitates the outflow of the fluid that continuously circulates in the anterior chamber of the eye, thereby reducing intraocular pressure. The effect on the iris sphincter muscle causes miosis (pupil constriction), which is a secondary therapeutic effect that can help in angle-closure glaucoma by pulling the iris away from the drainage angle.
Pilocarpine eye drops are primarily indicated for the treatment of primary open-angle glaucoma and angle-closure glaucoma. Open-angle glaucoma is the most common form, accounting for approximately 70–90% of all glaucoma cases worldwide, and is characterized by a gradual increase in intraocular pressure due to impaired aqueous humor drainage. Angle-closure glaucoma occurs when the iris physically blocks the drainage angle, and pilocarpine's miotic effect can help reopen this angle. According to the World Health Organization (WHO), glaucoma is the second leading cause of blindness globally, affecting an estimated 80 million people worldwide.
In its oral tablet form (marketed as Salagen), pilocarpine is used to treat xerostomia (dry mouth) resulting from radiation therapy for head and neck cancers or from Sjögren's syndrome, an autoimmune condition that damages moisture-producing glands. The oral formulation stimulates salivary gland secretion through the same muscarinic receptor activation mechanism.
Pilokarpin Karo Pharma eye drops are supplied as preservative-free single-dose units containing pilocarpine hydrochloride 2% (20 mg/ml). The preservative-free formulation is particularly beneficial for patients who require long-term treatment, as preservatives such as benzalkonium chloride can cause ocular surface toxicity with chronic use. Each single-dose unit contains enough solution for both eyes and should be discarded after a single use.
What Should You Know Before Using Pilokarpin Karo Pharma?
Contraindications
Pilokarpin Karo Pharma should not be used in the following situations:
- Hypersensitivity: If you are allergic to pilocarpine hydrochloride or any of the other ingredients (sodium chloride, hypromellose, sodium hydroxide, water for injection).
- Anterior uveitis or iritis: Active inflammation of the iris or uveal tract. Pilocarpine can worsen intraocular inflammation and increase the risk of posterior synechiae (adhesions between the iris and lens). If eye inflammation develops during treatment, stop using the drops and contact your doctor immediately.
- Conditions where miosis is undesirable: Certain types of secondary glaucoma where pupil constriction could worsen the condition, such as neovascular glaucoma or malignant glaucoma.
Warnings and Precautions
Talk to your doctor or pharmacist before using Pilokarpin Karo Pharma if any of the following apply:
- Retinal disease: Your doctor may need to perform a thorough eye examination (including dilated fundoscopy) before starting treatment. Pilocarpine-induced ciliary spasm can theoretically cause vitreous traction, which in rare cases may lead to retinal detachment, particularly in patients with pre-existing retinal pathology such as lattice degeneration or high myopia.
- Myopia and blurred vision: Pilocarpine contracts the ciliary muscle, which can cause accommodative spasm resulting in temporary myopia (near-sightedness) and blurred vision. This effect is typically most pronounced at the start of treatment and may diminish with continued use.
- Night vision: The miotic effect (pupil constriction) significantly reduces the amount of light entering the eye, which can substantially impair vision in dim lighting conditions. This is particularly relevant for nighttime driving.
- Visual disturbances: Contact your doctor immediately if you experience symptoms such as sudden flashes of light, new floaters, shadows or curtain-like effects in your peripheral vision, or sudden blurred vision. These may indicate retinal detachment, which requires urgent treatment (see Side Effects section).
- Contact lenses: If you wear contact lenses, remove them before instilling the eye drops. Wait at least 15 minutes before reinserting contact lenses.
Pregnancy and Breastfeeding
Pilokarpin Karo Pharma eye drops are not expected to pose a risk to the fetus when used as directed. The systemic absorption from topical ophthalmic administration is minimal. However, as a general precaution, always inform your doctor if you are pregnant, think you may be pregnant, or are planning to become pregnant. Your doctor will assess whether the benefit of treatment outweighs any potential risk.
Pilocarpine eye drops are considered compatible with breastfeeding. The amount of pilocarpine absorbed systemically from eye drops is very small and is unlikely to reach clinically significant levels in breast milk. The European Medicines Agency (EMA) guidance supports the use of pilocarpine eye drops during breastfeeding when clinically indicated. Nevertheless, consult your doctor before using any medication while breastfeeding.
Driving and Using Machines
Pilokarpin Karo Pharma has a moderate effect on the ability to drive and use machines. The medication can cause temporary myopia, blurred vision, and significantly reduced night vision in some users. These effects are caused by the ciliary muscle spasm and miosis (pupil constriction) that are inherent to pilocarpine's mechanism of action.
You should exercise particular caution when driving at night or operating machinery in poor lighting conditions. The miotic effect reduces the amount of light reaching the retina, which can make it difficult to see clearly in low-light environments. It is your responsibility to assess whether you are fit to drive or perform tasks requiring alertness. If you are unsure, discuss this with your doctor or pharmacist.
The visual side effects are typically most pronounced during the first few days of treatment and may improve as the eye adapts. However, the miotic effect persists throughout the duration of the drug's action (4–8 hours per dose), so driving in dim conditions should be avoided during this period.
How Does Pilokarpin Karo Pharma Interact with Other Drugs?
Because pilocarpine eye drops are applied topically to the eye and systemic absorption is limited, clinically significant drug interactions are less common compared to oral medications. However, several interactions warrant consideration, particularly in patients using multiple ophthalmic medications or taking systemic drugs with cholinergic or anticholinergic properties.
Ophthalmic Drug Interactions
When using multiple eye drops, allow at least 5 minutes between each medication to prevent dilution and washout effects. Pilocarpine is often used in combination with other glaucoma medications to achieve additive intraocular pressure reduction.
| Interacting Drug | Type | Effect | Recommendation |
|---|---|---|---|
| Beta-blockers (e.g., timolol eye drops) | Synergistic | Additive IOP reduction; potential additive bradycardia with systemic absorption | Commonly used together; wait 5 minutes between drops |
| Prostaglandin analogues (e.g., latanoprost) | Synergistic | Additive IOP-lowering effect through different mechanisms | May be combined; wait 5 minutes between drops |
| Anticholinergic agents (e.g., atropine, tropicamide) | Antagonistic | Directly oppose pilocarpine's miotic and IOP-lowering effects | Avoid concurrent ophthalmic use; discuss with doctor |
| Sympathomimetics (e.g., phenylephrine eye drops) | Partial antagonism | Mydriatic effect partially counteracts pilocarpine's miosis | Avoid concurrent use unless directed by ophthalmologist |
| Carbonic anhydrase inhibitors (e.g., dorzolamide) | Synergistic | Complementary IOP reduction | Safe combination; wait 5 minutes between drops |
| Systemic anticholinergics (e.g., oxybutynin, ipratropium) | Antagonistic | May partially reduce pilocarpine's efficacy | Monitor IOP; may need dose adjustment |
Systemic Interactions
While systemic absorption from pilocarpine eye drops is generally minimal, patients with compromised nasolacrimal drainage or those who do not use punctal occlusion after instillation may absorb higher amounts. In such cases, additive cholinergic effects could theoretically occur with systemic cholinergic medications such as cholinesterase inhibitors (donepezil, rivastigmine) used for Alzheimer's disease, or bethanechol used for urinary retention.
Patients taking systemic beta-blockers should be aware that the combination with topical pilocarpine can result in additive bradycardia (slow heart rate), although this is uncommon with properly administered eye drops. The use of nasolacrimal occlusion (gently pressing the inner corner of the eye) for 1–2 minutes after instillation reduces systemic absorption by approximately 60% and is recommended for all patients.
What Is the Correct Dosage of Pilokarpin Karo Pharma?
Always use this medicine exactly as your doctor has told you. Check with your doctor or pharmacist if you are not sure. The dosage is individually tailored by your prescribing physician based on factors including the type and severity of glaucoma, your target intraocular pressure, other medications you are using, and your individual response to treatment.
Adults
Standard Dosage — Pilocarpine 2% Eye Drops
Dose: 1 drop in the affected eye(s)
Frequency: 2–3 times per day
Duration: As directed by your doctor (typically long-term for chronic glaucoma)
Maximum daily doses: Usually not more than 4 times per day
In acute angle-closure glaucoma, your ophthalmologist may prescribe more frequent dosing initially (e.g., every 15–30 minutes for 1–2 hours) as part of emergency treatment to break the acute attack. This intensive dosing should only be done under medical supervision.
Children
The use of pilocarpine eye drops in children is generally limited and should only be prescribed by a pediatric ophthalmologist. Pilocarpine-induced accommodative spasm may cause more pronounced myopia in younger patients due to their greater accommodative amplitude. The dosage for children, when indicated, is typically the same as for adults (1 drop 2–3 times daily), but should be carefully individualized.
Elderly
No specific dose adjustment is required for elderly patients using pilocarpine eye drops. However, elderly patients may be more susceptible to the cholinergic side effects, particularly if they have limited nasolacrimal drainage function. The use of punctal occlusion after instillation is particularly important in this population. Elderly patients with cataracts should be aware that pilocarpine-induced miosis may further reduce visual acuity by reducing light entry through the lens opacity.
How to Use the Single-Dose Units
- Open the foil pouch at the score mark and detach one single-dose unit.
- Close the pouch by folding the edge to protect remaining units.
- Shake the contents down to the bottom of the single-dose unit.
- Open the unit by twisting off the wing tab.
- Tilt your head back slightly and pull down the lower eyelid to form a small pocket.
- Hold the unit close to your eye and gently squeeze to instill 1 drop into the conjunctival sac.
- Close your eye gently and press on the inner corner of the eye (nasolacrimal occlusion) for 1–2 minutes to reduce systemic absorption.
- Discard the single-dose unit after use, even if solution remains. Each unit contains enough for both eyes.
- Always use a new single-dose unit for each dosing occasion.
If you find it difficult to instill the eye drops, ask your pharmacist about a drop guide device. These assistive devices are designed to help position the single-dose unit correctly and direct the drop into the eye, which can be particularly helpful for patients with tremor or limited manual dexterity.
Missed Dose
If you forget a dose, instill it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not use a double dose to make up for a missed one. Maintaining a consistent dosing schedule helps ensure stable intraocular pressure control throughout the day.
Overdose
If you or someone else has accidentally swallowed pilocarpine eye drops, or if a child has ingested the medication, seek immediate medical attention or contact a poison control center. Systemic pilocarpine overdose can cause excessive salivation, sweating, nausea, vomiting, diarrhea, bradycardia (slow heart rate), bronchospasm, and in severe cases, hypotension and cardiac arrhythmias. Atropine is the specific antidote for pilocarpine toxicity.
Ocular overdose (instilling too many drops) may cause pronounced miosis, ciliary spasm with severe brow ache and headache, and excessive tearing. These effects are typically self-limiting and resolve as the drug wears off. If symptoms are severe or persistent, consult your doctor.
What Are the Side Effects of Pilokarpin Karo Pharma?
The side effects of pilocarpine eye drops are primarily related to its pharmacological action as a muscarinic receptor agonist. Local ocular effects result from ciliary muscle contraction and iris sphincter constriction, while systemic effects (which are uncommon with eye drops) result from cholinergic stimulation of various organ systems. The frequency and severity of side effects often decrease with continued use as the eye adapts to the medication.
Common
Affects more than 1 in 100 users
- Headache and brow ache — caused by ciliary muscle spasm; most pronounced at the start of treatment and typically diminishes over days to weeks
- Temporary myopia (near-sightedness) — accommodative spasm shifts the focal point, making distant objects appear blurry
- Blurred vision — transient effect lasting 1–2 hours after instillation
- Reduced night vision — miosis limits light entry; significant impact on driving in dim conditions
- Conjunctival irritation — redness, burning, or stinging sensation upon instillation
Rare
Affects fewer than 1 in 1,000 users
- Allergic reactions — contact dermatitis of the eyelids, conjunctival allergic reaction
- Cholinergic systemic effects — increased tear production, excessive sweating, slow heart rate (bradycardia), increased gastric acid production, diarrhea, and nausea
- Excessive tearing (epiphora) — stimulation of lacrimal gland secretion
Not Known
Frequency cannot be estimated from available data
- Retinal detachment — symptoms include sudden flashes of light, new floaters, shadows or a curtain-like effect in peripheral vision, or sudden blurred vision. Seek immediate medical attention if you experience any of these symptoms.
Contact your doctor or go to the nearest emergency department immediately if you experience sudden flashes of light, new or increasing floaters, a dark shadow or curtain moving across your visual field, or sudden loss of vision. These may be signs of retinal detachment, a potentially sight-threatening condition that requires urgent surgical intervention. The risk is higher in patients with high myopia, previous retinal pathology, or a history of retinal detachment.
Managing Common Side Effects
Many of the common side effects of pilocarpine diminish over the first 1–2 weeks of treatment as the ciliary muscle adapts. The following strategies may help manage these effects:
- Headache and brow ache: Over-the-counter analgesics (e.g., paracetamol/acetaminophen) can provide relief. The symptoms usually improve within the first week.
- Blurred vision: Instill the drops in the evening or before periods when sharp distance vision is not critical. The blurring is typically most pronounced in the first 30–60 minutes after instillation.
- Night vision impairment: Avoid nighttime driving when possible. Plan dosing schedules so that the drug's peak effect does not coincide with activities requiring good vision in dim lighting.
- Conjunctival irritation: The preservative-free single-dose formulation of Pilokarpin Karo Pharma minimizes ocular surface toxicity compared to preserved formulations.
Reporting Side Effects
It is important to report suspected side effects after a medicine has been authorized. This enables continuous monitoring of the medicine's benefit/risk balance. Healthcare professionals and patients are encouraged to report any suspected adverse reactions to their national pharmacovigilance authority (e.g., the EMA in Europe, the FDA MedWatch program in the United States, or the MHRA Yellow Card Scheme in the United Kingdom).
How Should You Store Pilokarpin Karo Pharma?
Proper storage of pilocarpine eye drops is essential to maintain the medication's stability and sterility. Because Pilokarpin Karo Pharma is supplied in preservative-free single-dose units, the absence of preservative means that once a unit is opened, it should not be stored for reuse.
- Unopened foil pouches: Store at room temperature (below 25°C / 77°F). Protect from light and excessive heat.
- Opened foil pouches: Once the aluminum foil pouch has been opened, the remaining single-dose units should be used within one month. Re-seal the pouch by folding the opened edge.
- Individual single-dose units: Discard after a single use, even if solution remains. Do not save or reuse opened units as contamination may occur.
- Expiry date: Do not use this medicine after the expiry date stated on the packaging. The expiry date refers to the last day of that month.
- Child safety: Keep out of sight and reach of children.
Do not throw away medicines via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer need. These measures help to protect the environment and prevent accidental exposure. Many pharmacies and healthcare facilities have take-back programs for unused medications.
What Does Pilokarpin Karo Pharma Contain?
Active Substance
The active substance is pilocarpine hydrochloride:
- Pilokarpin Karo Pharma 2%: 20 mg/ml pilocarpine hydrochloride
Inactive Ingredients (Excipients)
| Ingredient | Function | Notes |
|---|---|---|
| Sodium chloride | Tonicity agent | Adjusts solution osmolality to match tears (in 2% formulation) |
| Hypromellose | Viscosity enhancer | Increases contact time on the ocular surface for better absorption |
| Sodium hydroxide | pH adjuster | Adjusts pH to physiological range for comfort |
| Water for injections | Solvent/vehicle | Ultra-pure water meeting pharmacopeial standards |
Packaging
Each package contains 60 single-dose units made of polyethylene, packed in cards of 10 units enclosed in aluminum foil pouches. Each single-dose unit is embossed with "PIL" and marked on the wing tab with "2" for the 2% strength. The preservative-free formulation ensures ocular surface compatibility for long-term use, making it particularly suitable for patients with sensitive eyes or those who are intolerant to preservatives commonly used in multi-dose eye drop bottles.
Frequently Asked Questions About Pilokarpin Karo Pharma
Pilocarpine eye drops (such as Pilokarpin Karo Pharma) are applied directly to the eye and are used to treat glaucoma by lowering intraocular pressure. Pilocarpine tablets (marketed as Salagen, 5 mg) are taken orally and are used to treat xerostomia (dry mouth) caused by radiation therapy for head and neck cancers or by Sjögren's syndrome. The oral form stimulates salivary glands throughout the body, while the eye drops act locally on the eye with minimal systemic absorption. The side effect profiles differ significantly: oral pilocarpine is more likely to cause sweating, gastrointestinal symptoms, and other systemic cholinergic effects.
Pilocarpine eye drops begin to reduce intraocular pressure within 10–30 minutes of instillation. The peak pressure-lowering effect typically occurs at approximately 75 minutes, and the effect lasts between 4 and 8 hours depending on the concentration and individual patient response. The miotic effect (pupil constriction) begins within a few minutes and is usually fully apparent within 20–30 minutes. Because of the relatively short duration of action compared to newer glaucoma medications, pilocarpine typically requires dosing 2–3 times daily for sustained pressure control.
Yes, pilocarpine eye drops are often used in combination with other glaucoma medications such as beta-blockers (timolol), prostaglandin analogues (latanoprost), or carbonic anhydrase inhibitors (dorzolamide) when a single medication does not achieve adequate pressure control. When using multiple eye drops, wait at least 5 minutes between each medication to prevent the first drop from being washed out. Always follow your ophthalmologist's instructions regarding which medications to use and their timing.
The headache and brow ache associated with pilocarpine are caused by sustained contraction (spasm) of the ciliary muscle inside the eye. This muscle is involved in focusing the lens, and the continuous stimulation by pilocarpine can cause discomfort similar to the feeling of eye strain. In most patients, the ciliary muscle adapts to the medication within the first 1–2 weeks, and the headache significantly improves or resolves completely. Younger patients tend to experience more pronounced ciliary spasm due to their greater accommodative capacity. If the headache persists beyond 2 weeks or is severe, contact your doctor.
If you accidentally instill more than one drop, the excess will typically drain away naturally through the tear duct and down the cheek. You may experience more pronounced miosis (pupil constriction), temporary brow ache, and blurred vision, but these effects are self-limiting and will resolve as the medication wears off. There is no need for emergency treatment for ocular overdose in most cases. However, if a child or anyone accidentally swallows the contents of multiple single-dose units, seek immediate medical attention or contact a poison control center as systemic toxicity can occur.
Yes, pilocarpine continues to have an important role in glaucoma management despite the availability of newer medications. It is particularly valuable in angle-closure glaucoma (where it helps open the drainage angle by constricting the pupil), as an adjunctive therapy when other medications alone do not achieve target pressure, and in situations where patients cannot tolerate newer drug classes. Recently, there has been renewed interest in pilocarpine with the introduction of sustained-release formulations and its use in treating presbyopia (age-related difficulty with near vision). The WHO includes pilocarpine on its Model List of Essential Medicines, recognizing its ongoing importance in global healthcare.
References
This article is based on the following international medical guidelines, regulatory documents, and peer-reviewed research. All medical claims are supported by Level 1A evidence where available.
- European Medicines Agency (EMA). Pilocarpine Hydrochloride — Summary of Product Characteristics. EMA SmPC database. Available at: www.ema.europa.eu
- World Health Organization (WHO). WHO Model List of Essential Medicines — 23rd List, 2023. Geneva: World Health Organization; 2023. Pilocarpine listed under Section 21: Ophthalmological Preparations.
- European Glaucoma Society (EGS). Terminology and Guidelines for Glaucoma, 5th Edition. Savona, Italy: PubliComm; 2020.
- Weinreb RN, Aung T, Medeiros FA. The pathophysiology and treatment of glaucoma: a review. JAMA. 2014;311(18):1901-1911. doi:10.1001/jama.2014.3192
- National Institute for Health and Care Excellence (NICE). Glaucoma: diagnosis and management. NICE Guideline [NG81]. Updated 2022.
- U.S. Food and Drug Administration (FDA). Pilocarpine hydrochloride ophthalmic solution — Prescribing Information. FDA Drug Label database.
- British National Formulary (BNF). Pilocarpine hydrochloride. NICE-BNF. Available at: bnf.nice.org.uk
- Tham YC, Li X, Wong TY, et al. Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis. Ophthalmology. 2014;121(11):2081-2090. doi:10.1016/j.ophtha.2014.05.013
- American Academy of Ophthalmology (AAO). Preferred Practice Pattern: Primary Open-Angle Glaucoma. Updated 2023.
- Realini T. A history of glaucoma pharmacology. Optom Vis Sci. 2011;88(1):36-38. doi:10.1097/OPX.0b013e3182058ead
Medical Editorial Team
This article has been written and reviewed by qualified medical professionals with expertise in ophthalmology, pharmacology, and evidence-based medicine. Our editorial process follows the GRADE framework for evaluating evidence quality, and all content is reviewed against current international clinical guidelines.
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