Pilocarpine is a medication and natural alkaloid that primarily affects the parasympathetic nervous system. It is commonly used to treat various medical conditions, including:

• Glaucoma: Pilocarpine is often used as an eye drop to reduce intraocular pressure in the treatment of open-angle glaucoma and ocular hypertension. It works by causing the pupil to constrict and increasing the drainage of aqueous humor from the eye, which helps to lower eye pressure.
• Xerostomia (Dry Mouth): Pilocarpine can also be used to manage dry mouth, which can occur as a side effect of various medications or as a result of medical conditions like Sjögren's syndrome. It stimulates salivary gland function, increasing saliva production and relieving dry mouth symptoms.

Pilocarpine belongs to a class of drugs called cholinergic agonists, which mimic the action of acetylcholine, a neurotransmitter that activates the parasympathetic nervous system. By stimulating cholinergic receptors, pilocarpine can increase secretions in various parts of the body, such as the eye and salivary glands.

Pilocarpine (Salagen) oral formulation is used in the treatment of patients with dry mouth secondary to radiation of the head and neck. It may also be used in patients with Sjogren's syndrome.

Pilocarpine Uses:

• Xerostomia:
  • It is used for the symptomatic treatment of dry mouth that occurs due to salivary gland dysfunction in patients undergoing radiotherapy of the head and neck region.
  • It may be used for dry mouth in patients with Sjogren's syndrome.

Pilocarpine Dose in Adults

Dose in the treatment of Xerostomia: Oral:

For xerostomia associated with head and neck cancer:

• Start with 5 milligrams (mg) three times a day.
• Your doctor may adjust the dose depending on how well you respond to the treatment and how well you can tolerate it.
• The typical range of daily dosage is between 15 to 30 mg.
• The maximum amount you should take in a single dose is 10 mg.

For xerostomia related to Sjögren syndrome:

• Take 5 mg of pilocarpine four times a day.

Use in Children:

Not indicated.   

Pregnancy Category: C

• In studies with animals, some negative effects have been noticed during the process of reproduction.

Pilocarpine use during breastfeeding:

• We're not sure if pilocarpine passes into breast milk.
• Because there's a possibility of causing significant problems in a nursing baby, the manufacturer suggests that a choice be made between stopping breastfeeding or stopping the medication.

Dose in Kidney Disease:

• The manufacturer's instructions do not include any specific changes in the dosage.

Dose in Liver disease:

• Mild liver impairment (Child-Pugh score 5 to 6): No need to change the dosage; you can take it as prescribed.
• Moderate liver impairment (Child-Pugh score 7 to 9): Start with 5 mg twice a day. Your doctor may change the dose depending on how well you respond and how well you can tolerate it.
• Severe liver impairment (Child-Pugh score 10 to 15): It's not recommended to use this medication if you have severe liver problems.

Common Side Effects of Pilocarpine:

• Cardiovascular:
  • Flushing
• Central Nervous System:
  • Chills
  • Dizziness
  • Headache
• Gastrointestinal:
  • Nausea
• Genitourinary:
  • Urinary Frequency
• Neuromuscular & Skeletal:
  • Weakness
• Respiratory:
  • Rhinitis
• Miscellaneous:
  • Diaphoresis

Less Common Side Effects Of Pilocarpine:

• Miscellaneous:
  • Allergic Reaction
  • Voice Alteration
• Cardiovascular:
  • Facial Edema
  • Hypertension
  • Edema
  • Palpitation
  • Tachycardia
• Genitourinary:
  • Vaginitis
  • Urinary Incontinence
• Central Nervous System:
  • Pain
  • Somnolence
  • Fever
• Dermatologic:
  • Rash
  • Pruritus
• Gastrointestinal:
  • Vomiting
  • Constipation
  • Diarrhea
  • Dyspepsia
  • Salivation Increased
  • Stomatitis
  • Flatulence
  • Glossitis
  • Taste Perversion
• Respiratory:
  • Epistaxis
  • Sinusitis
  • Cough Increased
  • Dysphagia
• Neuromuscular & Skeletal:
  • Myalgias
  • Tremor
• Otic:
  • Tinnitus
• Ocular:
  • Abnormal Vision
  • Blurred Vision
  • Lacrimation
  • Amblyopia
  • Conjunctivitis

Contraindications to Pilocarpine:

Pilocarpine should not be used if:

• You are allergic to pilocarpine or any part of the medication.
• You have uncontrolled asthma.
• When you don't want to cause constriction of the pupil (miosis), for instance, in conditions like acute iritis or angle-closure glaucoma where making the pupil smaller is not desired.

Warnings and precautions

Cholelithiasis

• In individuals with cholelithiasis (gallstones) or problems with their biliary tract (the system that includes the gallbladder and bile ducts), pilocarpine should be used with caution.
• It's important to be cautious because this medication could potentially affect these conditions.

Cardiovascular disease

• Patients with cardiovascular disease should be cautious when using pilocarpine because it may cause temporary irregular heart rhythms and/or changes in blood flow, which can affect their heart condition.
• It's important to monitor and manage these effects in such individuals.

Hepatic impairment

• If you have moderate liver impairment, you can use pilocarpine, but you may need a dosage adjustment. It's important to be cautious.
• However, if you have severe liver impairment, it's not recommended to use pilocarpine because it may not be safe for you.

Nephrolithiasis

• Patients with a history of nephrolithiasis (kidney stones) should be cautious when using pilocarpine.
• This medication can potentially cause smooth muscle spasms, which might trigger renal colic (severe pain from a kidney stone) or ureteral reflux in individuals with kidney stones.
• It's important to be aware of this potential risk.

Respiratory problems

• In patients with controlled asthma, chronic bronchitis, or chronic obstructive pulmonary disease (COPD), the use of pilocarpine should be approached with caution.
• This medication has the potential to increase airway resistance, bronchial smooth muscle tone, and bronchial secretions, which can worsen respiratory symptoms in individuals with these conditions.
• Careful monitoring is advisable when using pilocarpine in such patients.

Pilocarpine(systemic): Drug Interaction

Monitoring Parameters:

Monitor ECG and the response to therapy.   

How to administer Pilocarpine?

Don't Take with a High-Fat Meal

• Avoid eating a high-fat meal when taking this medication.

Drink Enough Water

• Make sure to drink enough water while using this medication.
• If you don't drink enough, you might become dehydrated.

Mechanism of action of Pilocarpine:

Pilocarpine works by interacting with muscarinic (cholinergic) receptors in the body. This interaction leads to:

• An increase in the production of fluids from exocrine glands, like salivary and sweat glands. This can help with conditions like dry mouth.
• An increase in the tension or tone of smooth muscles in the digestive and urinary systems.

Onset of Action:

• It starts working about 20 minutes after you take it.

Maximum Effect:

• The most significant impact occurs around 1 hour after taking the medication.

Duration:

• It continues to work for 3 to 5 hours.

Half-life Elimination:

• Pilocarpine stays in your system for about 0.76 to 1.35 hours.
• If you have mild to moderate liver problems, it may take a bit longer (2.1 hours) to clear from your body.

Time to Peak in the Blood:

• The highest concentration in your bloodstream is reached in about 0.85 to 1.25 hours.
• If you eat a high-fat meal, it might take a little longer (1.47 hours).

Excretion:

• The body eliminates pilocarpine through urine.

International Brands of Pilocarpine:

• Salagen

Pilocarpine Brand Names in Pakistan: