Pilocarpine (Oral)

Orally administered, Pilocarpine can be used to treat dryness in the mouth, which can be caused by certain cancer treatments.

Overview

While Pilocarpine is notably used to treat ocular hypertension, when taken orally it is effective in treating the symptoms of a dry mouth, which can result from saliva gland damage caused by radiotherapy treatments of the head and neck to defeat cancer. The same condition can also be caused by an immune disease known as Sjogren's syndrome.

Pilocarpine belongs to a group of medicines known as cholinergic agonists. It functions by stimulating nerves to increase the amount of saliva produced by the body, facilitating easier speaking and swallowing.

This medication was first isolated in 1874 from the leaves of the Maranham Jaborandi plant, from which it is still primarily synthesized today. It is currently listed by the World Health Organization as an essential medicine, on account of its relatively low wholesale cost and high efficacy.

Pilocarpine can also be used off-label to treat other conditions, at the discretion of a prescribing doctor.

Type Of Medicine

  • Cholinergic agonist

Conditions Treated

  • Xerostomia
  • Ocular hypertension

Side Effects

Pilocarpine can potentially cause unwanted side effects along with its desired effects. The most common side effects reported by patients undergoing treatment with this medicine include the following:

  • Coughing
  • Chills
  • A feeling of heat or warmth
  • Redness or flushing of the skin, particularly on the neck or face
  • Joint pain
  • Indigestion
  • An increased need to urinate
  • Diarrhea
  • Runny nose
  • Nausea
  • Aches and pains in the muscles
  • Unusual weakness or tiredness
  • Sweating

Generally, most patients will only experience minimal side effects while taking Pilocarpine, if they experience any at all. Most doctors agree that the benefits of taking this medicine outweigh the risk of experiencing mild discomfort as a result of side effects. In many cases, a doctor or pharmacist will be able to recommend over the counter treatments or prescribed drugs to alleviate side effects.

Other side effects that are experienced rarely, albeit often enough to warrant mentioning, include the following:

  • Headaches
  • Fast heartbeat
  • Swelling of the fingers, face, feet or ankles
  • Shaking or trembling
  • Difficulty swallowing
  • Vision loss
  • Changes in the voice
  • Vomiting
  • Retaining more body water

Because Pilocarpine can affect vision and co-ordination, patients are advised to avoid driving or operating heavy machinery until it has been observed that these side effects do not affect them individually. This is to avoid the risk of injury or death to the patient and other road users.

Some side effects may not be listed. Patients who experienced unlisted side effects are advised to consult with their doctor as soon as possible and report their findings to the FDA.

Dosage

As with all medicines, it is imperative that patients only take Pilocarpine as prescribed by a qualified physician. This means that patients should not take any more Pilocarpine than they have been advised to, either in terms of frequency or dose size. In addition to this, patients must be willing to stop taking Pilocarpine if advised to do so by their doctor or healthcare provider, even if they still have a supply of the drug remaining.

Pilocarpine can be taken with or without food. Dosages may vary dependent on the condition and the needs of the patient, and patients are recommended to pay close attention to the instructions of their doctor at the time the medication is prescribed. The patient may also follow the instructions printed on the side of the medicine, as these should match with the doctor's recommendations. The strength of the medicine, number of doses each day and length of time the patient is expected to take the medicine all play a part in determining the size of the dose.

For the treatment of xerostomia in patients with head and neck cancers, the patient should take 5mg of Pilocarpine, three times a day, titrated upwards until the optimum dose is discovered. Patients should not take more than 10mg of Pilocarpine at a time (maximum 30mg per day).

Patients with Sjorgen's syndrome should take 5mg of Pilocarpine, four times a day. If the patient has any form of liver impairment, this dose should be adjusted downwards to 5mg taken twice daily. The lowest effective dose should always be used for maintenance.

While the manufacturers of Trihexyphenidyl provide general dose instructions, it should be reiterated that these are merely guidelines which can be altered by the patient's doctor. A doctor will take into account the height, weight, age and condition of the patient, among other factors, when determining dose size.

There are no recommended Pilocarpine dose sizes for children. Instead, the manufacturer leaves pediatric dose size choices to the discretion of the prescribing doctor.

Patients are advised against taking double doses. If a patient misses a dose, they can simply take the missed dose as soon as they realize, unless it is near the time to take the next scheduled dose. In this instance, the patient should simply omit the missed dose and continue with their dose schedule as normal.

The following are symptoms of Pilocarpine overdose:

  • Chest pain
  • Fainting
  • Slow, fast or irregular heartbeat
  • Severe headache
  • Stomach pains or cramps
  • Shaking or trembling
  • Vision loss
  • Severe, continued vomiting

Patients who experience one or more of these symptoms are advised to contact their local poison control center on 1800-1222-222 or emergency services on 911. Alternatively, a patient may make their way to the nearest ER, provided it is in close enough proximity.

Interactions

All medicines have the potential to interact with other chemicals or drugs within the human body, and these interactions can change the effects of each medication. In some cases, interactions can result in a medicine becoming ineffective in treating the condition it was prescribed to combat. In other instances, interactions can cause dangerous and even fatal side effects. Because of these risks, it is important that the patient keeps a full, detailed list of all medicines they are currently taking. This extends to over the counter remedies, complimentary medicines, vitamins and herbal supplements, alongside prescribed drugs.

The following is a list of medicines known to interact negatively with Pilocarpine. Patients who are currently undergoing treatment with one or more of these drugs should inform their doctor before taking their first dose of Pilocarpine:

  • Umeclidinium/Vilanterol
  • Umeclidinium
  • Trospium
  • Tropicamide Ophthalmic
  • Trihexyphenidyl
  • Tolterodine
  • Tiotropium
  • Timolol Ophthalmic
  • Timolol
  • Thalidomide
  • Sotalol
  • Solifenacin
  • Scopolamine Ophthalmic
  • Scopolamine
  • Quinidine
  • Propranolol
  • Propantheline
  • Procyclidine
  • Procainamide
  • Pindolol
  • Phenylephrine/Scopolamine Ophthalmic
  • Penbutolol
  • Oxybutynin
  • Olodaterol/Tiotropium
  • Nebivolol/Valsartan
  • Nebivolol
  • Nadolol
  • Metoprolol
  • Metipranolol Ophthalmic
  • Methscopolamine/Pseudoephedrine
  • Methscopolamine/Phenylephrine
  • Methscopolamine
  • Mepenzolate
  • Meclizine
  • Levobunolol Ophthalmic
  • Levobetaxolol Ophthalmic
  • Lactobacillus Acidophilus/Methscopolamine
  • Labetalol
  • Ivabradine
  • Ipratropium
  • Hyoscyamine/Phenyltoloxamine
  • Hyoscyamine/Phenobarbital
  • Hyoscyamine/Methenamine/Methylene Blue/Sodium Biphosphate
  • Hyoscyamine/Methenamine/Methylene Blue/Phenyl Salicylate/Sodium Biphosphate
  • Hyoscyamine/Methenamine/Methylene Blue/Phenyl Salicylate
  • Hyoscyamine/Methenamine
  • Hyoscyamine
  • Hydroxyamphetamine/Tropicamide Ophthalmic
  • Hydrochlorothiazide/Timolol
  • Hydrochlorothiazide/Propranolol
  • Hydrochlorothiazide/Metoprolol
  • Homatropine/Hydrocodone
  • Homatropine Ophthalmic
  • Glycopyrrolate/Indacaterol
  • Glycopyrrolate
  • Formoterol/Glycopyrrolate
  • Fluticasone/Umeclidinium/Vilanterol
  • Flavoxate
  • Fingolimod
  • Esmolol
  • Dorzolamide/Timolol Ophthalmic
  • Disopyramide
  • Dimenhydrinate
  • Dicyclomine
  • Dextromethorphan/Quinidine
  • Dexchlorpheniramine/Methscopolamine/Pseudoephedrine
  • Dexchlorpheniramine/Methscopolamine/Phenylephrine
  • Darifenacin
  • Cyclopentolate/Phenylephrine Ophthalmic
  • Cyclopentolate Ophthalmic
  • Cyclizine
  • Crizotinib
  • Clozapine
  • Clidinium
  • Chlorpheniramine/Methscopolamine/Phenylephrine
  • Chlorpheniramine/Methscopolamine
  • Chlordiazepoxide/Methscopolamine
  • Chlordiazepoxide/Clidinium
  • Cellulase/Hyoscyamine/Pancrelipase/Phenyltoloxamine
  • Carvedilol
  • Carteolol Ophthalmic
  • Carteolol
  • Carbinoxamine/Methscopolamine/Pseudoephedrine
  • Butabarbital/Hyoscyamine/Phenazopyridine
  • Brompheniramine/Chlorpheniramine/Methscopolamine/Phenylephrine/Pseudoephedrine
  • Brimonidine/Timolol Ophthalmic
  • Brigatinib
  • Bisoprolol/Hydrochlorothiazide
  • Bisoprolol
  • Biperiden
  • Betaxolol Ophthalmic
  • Betaxolol
  • Benztropine
  • Benzoic Acid/Hyoscyamine/Methenamine/Methylene Blue/Phenyl Salicylate
  • Bendroflumethiazide/Nadolol
  • Belladonna/Opium
  • Belladonna/Ergotamine/Phenobarbital
  • Belladonna/Caffeine/Ergotamine/Pentobarbital
  • Belladonna/Butabarbital
  • Belladonna
  • Atropine/Pralidoxime
  • Atropine/Phenobarbital
  • Atropine/Hyoscyamine/Phenobarbital/Scopolamine
  • Atropine/Edrophonium
  • Atropine/Diphenoxylate
  • Atropine/Difenoxin
  • Atropine/Chlorpheniramine/Hyoscyamine/Pseudoephedrine/Scopolamine
  • Atropine/Chlorpheniramine/Hyoscyamine/Phenylephrine/Scopolamine
  • Atropine/Chlorpheniramine/Hyoscyamine/Phenylephrine/Phenylpropanolamine/Scopolamine
  • Atropine Ophthalmic
  • Atropine
  • Atenolol/Chlorthalidone
  • Atenolol
  • Amylase/Cellulase/Hyoscyamine/Lipase/Phenyltoloxamine/Protease
  • Alectinib
  • Albuterol/Ipratropium
  • Aclidinium
  • Acebutolol

Warnings

Patients who have ever suffered an allergic reaction to this medicine or any other medicine should inform their doctor prior to taking it. In rare cases, patients may experience hypersensitive reactions to Pilocarpine.

This medicine may not be suitable for patients with the following:

Patients with one or more of these conditions should be monitored when taking Pilocarpine, and the prescribing doctor should exercise caution when determining dose size.

Pilocarpine is classed as a pregnancy category C medicine. This means that it is unknown whether this medication has any effect on developing fetuses. It is also unknown whether Pilocarpine is excreted into human breast milk. Patients who are pregnant or planning on becoming pregnant in the near future are advised to discuss the risks of using Pilocarpine during pregnancy with their doctor.

Patients are advised to drink plenty of fluids while taking this medicine, as it can cause excess sweating. Patients who do not drink enough liquids while taking Pilocarpine are at an increased risk of becoming dehydrated.

This medicine can potentially cause vision problems, particularly at night or in low light. Patients are, therefore, advised to exercise caution when driving or undertaking tasks in the evening or night time.

Storage

Pilocarpine should be stored out of direct sunlight, at room temperature, in the packaging it was shipped in. It must not be frozen, and should be kept away from heat and moisture it is, therefore, unsuitable for storage in a bathroom. It should also be kept out of the reach of children and pets.

Patients should take great care when disposing of unwanted, unused or expired Pilocarpine tablets, and should do so in accordance with state law. Many pharmacies offer take-back schemes, where they will recycle or dispose of unused medicines, free of charge; patients are advised to take advantage of such programs.

Summary

While Pilocarpine can be a greatly beneficial drug to both sufferers of head and neck cancer and Sjorgen's syndrome alike, it can pose a risk to those who do not communicate effectively with their healthcare providers.

As a treatment designed to alleviate symptoms of xerostomia and the side effects of radiotherapy, Pilocarpine facilitates greater saliva production, which helps to combat dry mouth, difficulty swallowing and difficulty speaking. However, it can also cause excess sweating and also impair co-ordination, which can potentially give rise to perilous situations. It is, therefore, in the best interests of the patient to be forthcoming with as much information as possible about their own medical history, including details of any hereditary illnesses, when talking to their doctor.

When taken properly, Pilocarpine can provide relief of symptoms and side effects that would otherwise have been untreatable. In many cases, this can provide the patient with a much greater quality of life. In order to achieve this, patient and doctor must work together to ascertain the optimum dosage and frequency of treatment.