Pilocarpine/ Pharmacological actions, effects Pilocarpine


The natural alkaloid compound pilocarpine is obtained from the leaves of the Pilocarpus plant, which is indigenous to South America. Its pharmacological benefits have long been recognized, especially in ophthalmology and the treatment of specific medical disorders.

Here are some key points about pilocarpine:

  1. Ophthalmic Use: Pilocarpine is primarily known for its use in the treatment of glaucoma, a condition characterized by increased intraocular pressure. It works by stimulating the contraction of the iris sphincter muscle, leading to the opening of the trabecular meshwork and facilitating the drainage of aqueous humor from the eye. This helps to reduce intraocular pressure and manage glaucoma.

  2. Salivary Stimulation: Pilocarpine can also be used to stimulate saliva production. It is sometimes prescribed to individuals experiencing dry mouth (xerostomia) due to certain medical conditions, medications, or radiation therapy.

  3. Other Medical Uses: Pilocarpine has been investigated for its potential in other medical conditions, including Sjögren’s syndrome (an autoimmune disorder that affects moisture-producing glands) and as a treatment for dry eye.

  4. Side Effects: Common side effects of pilocarpine may include sweating, increased salivation, blurred vision, and gastrointestinal symptoms. These side effects are often related to its cholinergic effects.

  5. Contraindications: Pilocarpine is generally contraindicated in individuals with certain eye conditions, such as iritis or uveitis, where constriction of the pupil may be harmful.

  6. Forms of Administration: Pilocarpine is available in various forms, including eye drops, oral tablets, and oral solutions. The specific form and dosage depend on the medical condition being treated.

Pharmacological actions Pilocarpine:

Pilocarpine exerts its pharmacological actions primarily through its cholinergic effects, as it acts as a muscarinic acetylcholine receptor agonist. Here are the key pharmacological actions of pilocarpine:

  1. Miosis (Pupil Constriction): Pilocarpine stimulates the muscarinic receptors in the eye, specifically the iris sphincter muscle. This leads to the contraction of the muscle, resulting in miosis (constriction of the pupil). The constriction of the pupil facilitates the outflow of aqueous humor from the eye, which is beneficial in the treatment of glaucoma.

  2. Decreased Intraocular Pressure: By causing miosis and facilitating the drainage of aqueous humor, pilocarpine helps reduce intraocular pressure. This makes it a valuable medication for the management of open-angle glaucoma, where elevated intraocular pressure is a major concern.

  3. Increased Salivation: Pilocarpine stimulates the salivary glands, leading to an increase in salivation. This effect is utilized in the management of conditions characterized by dry mouth (xerostomia), such as those resulting from certain medications, radiation therapy, or Sjögren’s syndrome.

  4. Sweating: Pilocarpine can stimulate sweat gland activity, leading to increased sweating. This effect is less commonly utilized therapeutically and can contribute to some of the side effects associated with the drug.

  5. Cardiovascular Effects: Pilocarpine can have cardiovascular effects, including bradycardia (slowed heart rate) and vasodilation. These effects are attributed to its activation of muscarinic receptors in the heart and blood vessels.

  6. Gastrointestinal Effects: Pilocarpine may also stimulate smooth muscle contraction in the gastrointestinal tract, leading to increased peristalsis. This effect is generally mild and is not a primary therapeutic use of the drug.

It’s important to note that while pilocarpine’s actions on muscarinic receptors are the basis for its therapeutic effects, they can also lead to side effects. For example, excessive stimulation of muscarinic receptors can cause blurred vision, headache, sweating, and other cholinergic symptoms. The dosage and administration of pilocarpine are carefully regulated to balance its therapeutic benefits with potential side effects. Patients using pilocarpine should be monitored for adverse reactions, and the medication should be used under the guidance of a healthcare professional.

effects of Pilocarpine:

The effects of pilocarpine can vary depending on the dosage, route of administration, and the specific condition being treated. Here are some of the primary effects associated with the use of pilocarpine:

  1. Ophthalmic Effects:

    • Miosis (Pupil Constriction): Pilocarpine causes constriction of the pupil by stimulating the iris sphincter muscle. This effect is utilized in the treatment of glaucoma to improve the outflow of aqueous humor and reduce intraocular pressure.
    • Improved Aqueous Humor Drainage: Pilocarpine facilitates the drainage of aqueous humor from the eye, helping to lower intraocular pressure.
  2. Salivary Stimulation:

    • Increased Salivation: Pilocarpine stimulates the salivary glands, leading to an increase in saliva production. This effect is used to manage conditions of dry mouth (xerostomia).
  3. Sweating:

    • Stimulation of Sweat Glands: Pilocarpine can induce sweating, an effect that is generally not the primary therapeutic use but can contribute to side effects.
  4. Cardiovascular Effects:

    • Bradycardia (Slowed Heart Rate): Pilocarpine may cause a decrease in heart rate due to its effects on muscarinic receptors in the heart.
    • Vasodilation: Pilocarpine’s activation of muscarinic receptors can lead to blood vessel dilation.
  5. Gastrointestinal Effects:

    • Stimulation of Gastrointestinal Smooth Muscle: Pilocarpine may increase peristalsis in the gastrointestinal tract, potentially leading to increased bowel movements.
  6. Cholinergic Side Effects:

    • Blurred Vision: Excessive stimulation of muscarinic receptors in the eye can lead to blurred vision.
    • Headache: Some individuals may experience headaches as a side effect.
    • Nausea and Vomiting: Gastrointestinal effects, such as increased peristalsis, may lead to nausea and vomiting.

It’s important to note that the effects of pilocarpine are primarily due to its actions on muscarinic acetylcholine receptors. While these effects are therapeutically beneficial in conditions like glaucoma and dry mouth, they can also result in side effects, especially if the dosage is too high. The use of pilocarpine should be carefully monitored by healthcare professionals to balance its therapeutic benefits with potential adverse reactions.


To sum up, pilocarpine is a drug that predominantly functions as a muscarinic acetylcholine receptor agonist and has a variety of pharmacological effects. Its main uses are in the induction of miosis for the treatment of glaucoma and the improvement of aqueous humor drainage, as well as the stimulation of salivary glands for the treatment of dry mouth diseases. Pilocarpine has many therapeutic advantages, but it can also have a number of adverse effects, including increased perspiration, impaired vision, and gastrointestinal problems. As a result, medical monitoring and careful dose control are required.

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