Pilocarpine

Pilocarpine is a medicinal substance used in medicine, mainly in ophthalmology. It is an alkaloid extracted from the Pilocarpus plant. Pilocarpine is mainly used to treat glaucoma, a disease characterized by increased intraocular pressure, which can lead to damage to the optic nerve and loss of vision.

The mechanism of action of pilocarpine is related to its ability to stimulate contraction of radial iris muscles, which leads to pupil dilation and increased outflow of intraocular fluid. This in turn reduces intraocular pressure, reducing the risk of optic nerve damage and preserving vision.

Pilocarpine can be available in various forms for use including eye drops, gel forms and injections. It is usually administered as a medication under the supervision of a doctor, as it requires close monitoring and may have side effects.

Indications Pilocarpine

1. Glaucoma: The main use of pilocarpine is in the treatment of glaucoma, a disease characterized by increased intraocular pressure. Pilocarpine helps to reduce intraocular pressure by increasing the outflow of intraocular fluid.
2. Preparing the eye for surgical procedures: Pilocarpine can be used to dilate the pupil and reduce intraocular pressure in the preoperative period before eye surgery.
3. Diagnosis of eye diseases: Pilocarpine is sometimes used as a diagnostic tool to evaluate the eye and its structures, such as the iris and lens.
4. Miosis: Pilocarpine may be used to induce miosis (pupil constriction) in clinical trials or in certain medical procedures.

Release form

Eye drops: The most commonly used form of pilocarpine, applied directly into the eye to treat glaucoma and other conditions associated with increased intraocular pressure. Pilocarpine eye drops are available in various concentrations, usually 1% to 4%.

Pharmacodynamics

1. Mechanism of Action: Pilocarpine is an agonist of muscarinic cholinoreceptors, which are found in various organs and tissues such as salivary glands, sweat glands, ocular smooth muscle, and the cardiovascular system. Activation of these receptors results in increased salivary fluid secretion, sweat, contraction of the pupil of the eye, decreased intraocular pressure and increased gastrointestinal peristalsis.
2. Lowering intraocular pressure: Pilocarpine is used to treat glaucoma because its miotic action helps to dilate the angle of the anterior chamber of the eye and improve drainage of intraocular fluid, leading to a decrease in intraocular pressure.
3. Increased saliva and sweat secretion: This effect is used in medicine to treat xerostomia (dry mouth) and xerosis of the skin, and to diagnose salivary gland function.
4. Increase in intestinal peristalsis: Pilocarpine may be used to stimulate digestion and treat intestinal atony.
5. Treatment of asthma: In some cases pilocarpine may be used to widen the airways and improve expectoration.

Pharmacokinetics

1. Absorption: Pilocarpine may be absorbed through mucous membranes when used as eye drops or sublingually for the treatment of xerostomia.
2. Distribution: After absorption, pilocarpine is rapidly distributed to organs and tissues, including the eyes and oral mucous membranes.
3. Metabolism: Pilocarpine is metabolized in the liver to form inactive metabolites.
4. Excretion: Metabolites of pilocarpine and pilocarpine itself are excreted mainly through the kidneys with urine.

Dosing and administration

Pilocarpine eye drops:

1. For the treatment of glaucoma:

   • Concentration and frequency of administration depend on the severity of the disease and response to treatment.
   • The usual starting dose is 1-2 drops of a 1-2% solution into the affected eye 3-4 times a day.
   • The doctor may adjust the dose depending on the effectiveness of treatment and tolerability.

2. Instructions for use:

   • Wash your hands thoroughly before using the drops.
   • Do not touch the tip of the dropper to the skin or the surface of the eye to avoid contamination.
   • After injecting, lightly press the corner of the eye near the nasal bridge to minimize the drug from entering the rest of the body.

Important points:

• When using pilocarpine in any form, it is important to use caution and watch out for possible side effects such as sweating, nausea, rapid heartbeat, blurred vision, etc.
• Before starting treatment with pilocarpine, it is important to notify your doctor of all existing medical conditions and medications being taken to avoid unwanted interactions.
• See your doctor regularly to monitor your condition and adjust treatment if necessary.

Use Pilocarpine during pregnancy

The use of Pilocarpine during pregnancy should be limited and only under the strict supervision of a physician.

There is currently insufficient data on the safety of Pilocarpine for pregnant women, so it is recommended to avoid its use during pregnancy, especially in the first trimester. If it is necessary to treat glaucoma or other eye conditions in a pregnant woman, the doctor may consider the benefit of the drug and the potential risks to the baby to make an informed decision.

Contraindications

1. Asthma: Pilocarpine may worsen asthma symptoms or cause bronchial spasms in some patients, so it should be used with caution in people with asthma.
2. Heart Disease: Use of pilocarpine can increase heart rate and increase heart activity, which can be dangerous for people with heart conditions such as arrhythmias or heart failure.
3. Serious hepatic and renal impairment: Pilocarpine is metabolized and excreted through the liver and kidneys, therefore it should be used with caution in patients with serious impairment of these organs.
4. Hypersensitivity: People with known hypersensitivity to pilocarpine or other components of the drug should avoid its use.
5. Pregnancy and lactation: The safety of pilocarpine during pregnancy or lactation has not been established, therefore its use in these cases should be under medical supervision.
6. Pediatric: Data on the safety and efficacy of pilocarpine in children are limited; therefore, its use in children should be used only when prescribed by a physician.

Side effects Pilocarpine

1. Changes in vision: Pupil constriction (miosis) may occur, which can lead to changes in vision in the dark or in low light.
2. Application site reactions: Include eye redness, burning, irritation and itching.
3. Ocular reactions: There may be a transient increase in intraocular pressure, especially in patients with angular closure of the anterior chambers of the eye. Redness of the eyes, lacrimation and a feeling of sand in the eyes may also occur.
4. Systemic side effects: Possible side effects from other organs and body systems, such as headache, dizziness, nausea, increased sweating, weakness, bradycardia (slow heart rate) and others.
5. Allergic reactions: Rarely, allergic reactions such as itching, skin rashes, swelling of the eye lid or face, difficulty breathing and anaphylactic shock may occur.

Overdose

1. Heavy salivation: Excessive saliva production can lead to discomfort and difficulty swallowing.
2. Sweating: Excessive sweating may occur as a result of pilocarpine overdose.
3. Miosis (constriction of the pupils): This is one of the typical effects of pilocarpine, but in case of overdose miosis may be more pronounced and prolonged.
4. Myosaria (accommodation spasms): This is a condition in which focusing the eye on close objects becomes difficult due to excessive constriction of the pupils.
5. Decreased heart rate and blood pressure: Pilocarpine may cause bradycardia and hypotension.
6. Feelings of nausea and vomiting: These symptoms may occur due to stimulation of receptors in the gastrointestinal tract.

Interactions with other drugs

1. Antiglaucoma drugs: Use of pilocarpine with other antiglaucoma drugs may increase its effect and cause an increase in side effects such as eye irritation and dry mouth.
2. Anticholinergic drugs: The use of pilocarpine together with anticholinergic drugs (e.g. Atropine) may reduce its efficacy.
3. Drugs affecting the cardiovascular system: Pilocarpine may cause changes in the cardiovascular system, therefore it should be used with caution in combination with other drugs affecting heart rhythm or blood pressure.
4. Antidepressants and drugs for the treatment of Parkinson's disease: Pilocarpine may increase the side effects of antidepressants and drugs for the treatment of Parkinson's disease.
5. Drugs to enhance salivary gland secretion: When pilocarpine is used to treat xerostomia, its effect may be enhanced when combined with other drugs that stimulate salivary gland secretion.