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  In this Article
 »  Pilocarpine
 »  Pharmacology
 »  Cautions
 »  Undesirable effects
 »  Dose and Use
 »  Supply
 »  References

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PHARMACOTHERAPY
Year : 2006  |  Volume : 12  |  Issue : 2  |  Page : 65-67

Drug highlight: Pilocarpine


1 Emeritus Clinical Reader in Palliative Medicine, Oxford University, United Kingdom
2 Senior Editor, palliativedrugs.com, Nottingham, United Kingdom
3 Macmillan Clinical Reader in Palliative Medicine and Medical Oncology, Nottingham University, United Kingdom
4 Senior Pharmacist, Christian Medical College, Vellore, India

Correspondence Address:
Andrew Wilcock
Hayward House, Nottingham University Hospitals NHS Trust, City Hospital Campus, Nottingham, NG5 1PB
United Kingdom
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0973-1075.30247

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How to cite this article:
Wilcock A, Twycross R, Mortimer J, Tresiamma M P. Drug highlight: Pilocarpine. Indian J Palliat Care 2006;12:65-7

How to cite this URL:
Wilcock A, Twycross R, Mortimer J, Tresiamma M P. Drug highlight: Pilocarpine. Indian J Palliat Care [serial online] 2006 [cited 2019 Sep 22];12:65-7. Available from: http://www.jpalliativecare.com/text.asp?2006/12/2/65/30247



 » Pilocarpine Top


Class: Parasympathomimetic.

Indications: Xerostomia (dry mouth) after radiation for head and neck cancer, dry mouth (and dry eyes) in Sj φgren's syndrome and drug-induced dry mouth.

Contra-indications: Intestinal or urinary obstruction, or where increased intestinal or urinary tract motility could be harmful (e.g., after recent surgery); uncontrolled asthma, chronic obstructive pulmonary diseases (COPD) or cardiovascular disease; acute iritis.


 » Pharmacology Top


Pilocarpine is a parasympathomimetic (predominantly muscarinic) drug with mild b-adrenergic activity which stimulates secretion from exocrine glands, including salivary glands.[1] The prophylactic use of pilocarpine 5 mg q.d.s. in patients receiving head and neck radiation (starting simultaneously and continuing for 4-6 weeks after the radiation is completed) has been shown to reduce the decrease in unstimulated salivary flow,[2],[3] and to actually increase it in about 1/4 of patients.[2],[3] Despite this objective improvement, a large placebo-controlled trial (n=245) failed to show symptomatic benefit.[2],[4] On the other hand, about 50% of patients with dry mouth several weeks or months after radiation will respond to pilocarpine although benefit may take 3 months to become apparent.[5],[6] Thus, failure to demonstrate symptomatic benefit from prophylactic use may relate to a too short a treatment period or the presence of concurrent problems, e.g., mucositis.

About 90% of patients with drug-induced dry mouth respond to pilocarpine with benefit seen immediately.[6] In a controlled study, 1/2 of the patients preferred pilocarpine (because it was more effective) and 1/2 preferred mucin-based artificial saliva (mainly because it was a spray and not a tablet).[6] Undesirable effects were much more common in patients receiving pilocarpine (84% vs. 22%), which resulted in 1/4 of the patients withdrawing from the study.

Cheaper alternatives to pilocarpine, e.g., bethanechol are used at some centres.[7],[8],[9],[10]

Bio-availability 96% PO.

Onset of action 20 min (drug-induced dry mouth); up to 3 months (after radiation).

Time to peak plasma concentration 1h.

Plasma halflife 1h.

Duration of action 3-5h.


 » Cautions Top


Pilocarpine may antagonize the effects of antimuscarinic drugs, e.g., inhaled ipratropium bromide. Concurrent use with b-adrenergic antagonists (b-blockers) may cause cardiac conduction disturbances.

Cognitive or psychiatric disorder, epilepsy,  Parkinsonism More Details, narrow-angle glaucoma. Miosis may affect vision and driving ability. Cardiovascular disease (changes in haemodynamics or heart rhythm), hyperthyroidism, asthma and COPD (increased bronchial smooth muscle tone, airway resistance and bronchial secretions). Peptic ulcer (increased acid secretion), gallstones or biliary tract disease (increased biliary smooth muscle contraction). Moderate-severe liver impairment (reduce dose). Renal impairment (insufficient human data on metabolism and excretion), kidney stones (potential for renal colic). Increased sweating may exacerbate dehydration in patients unable to drink sufficient fluids.


 » Undesirable effects Top


For full list, see manufacturer's summary of product characteristics.

Very common: (>10%): headache, flu-like syndrome, urinary frequency, sweating.

Common: (<10%, >1%): dizziness, asthenia, chills, blurred vision, eye pain, conjunctivitis, flushing, palpitations, hypertension (following initial hypotension), rhinitis, abdominal pain, dyspepsia, nausea, vomiting, diarrhoea or constipation, rash, pruritus.


 » Dose and Use Top


In drug-induced dry mouth the effective dose is generally 5 mg ter die sumendus (three times a day) (t.d.s.) or less, whereas after radiation the effective dose is generally 5-10 mg t.d.s.:

  • start with 5 mg t.d.s. with meals
  • if necessary and if tolerated, increase the dose after 2 days if the dry mouth is drug-induced, and after 4 weeks if radiation-induced
  • maximum dose 10 mg t.d.s.
  • if no improvement, stop after 2 days if the dry mouth is drug-induced, and after 12 weeks if radiation-induced
  • in patients with moderate-severe liver impairment start on a lower dose, e.g., 5 mg o.d. and work up to 5 mg t.d.s. if well tolerated.


It is cheaper to give pilocarpine eyedrops PO than to prescribe tablets, e.g., pilocarpine 4% 2-3 drops t.d.s. = 4-6 mg. Maximum cost/month about Rs. 300, whereas tablets would cost Rs. 600.

If bethanechol is used instead for drug-induced dry mouth:

  • start with 25 mg t.d.s. 30 min ante cibum (before food).
  • reduce dose to 10 mg t.d.s. if patients experience excessive salivation.


Undesirable effects are similar to pilocarpine but generally less severe, either because the equivalent dose is less or the muscarinic receptor binding pattern of bethanechol is different.


 » Supply Top


Pilomax® (Sun Pharma)

Tablets 5 mg, 28 days @ 5 mg t.d.s. = Rs. 600.

Eyedrops 4% (40 mg/1 ml), 5 ml lasts 11-16 days @ 2-3 drops t.d.s = Rs. 105.

 
 » References Top

1.Anonymous. Oral pilocarpine for xerostomia. Med Lett Drugs Ther 1994; 36:76.  Back to cited text no. 1    
2.Scarantino C, LeVeque F, Swann RS, White R, Schulsinger A, Hodson DI, et al . Effect of pilocarpine during radiation therapy: Results of RTOG 97-09, a phase III randomized study in head and neck cancer patients. J Support Oncol 2006; 4(5):252-8.  Back to cited text no. 2    
3.Nyarady Z, Nemeth A, Ban A, Mukics A, Nyarady J, Ember I, et al . A randomized study to assess the effectiveness of orally administered pilocarpine during and after radiotherapy of head and neck cancer. Anticancer Res 2006; 26(2B):1557-62.  Back to cited text no. 3    
4.Warde P, O'Sullivan B, Aslanidis J, Kroll B, Lockwood G, Waldron J, et al . A Phase III placebo-controlled trial of oral pilocarpine in patients undergoing radiotherapy for head-and-neck cancer. Int J Radiat Oncol Biol Phys 2002; 54(1):9-13.  Back to cited text no. 4    
5.Rieke JW, Hafermann MD, Johnson JT, LeVeque FG, Iwamoto R, Steiger BW, et al . Oral pilocarpine for radiation-induced xerostomia: Integrated efficacy and safety results from two prospective randomized clinical trials. Int J Radiat Oncol Biol Phys 1995;31(3):661-9.  Back to cited text no. 5    
6.Davies A, Daniels C, Pugh R, Sharma K. A comparison of artificial saliva and pilocarpine in the management of xerostomia in patients with advanced cancer. Palliat Med 1998;12:105-11.  Back to cited text no. 6    
7.Everett H. The use of bethanechol chloride with tricyclic antidepressants. American Journal of Psychiatry 1975;132:1202-4.  Back to cited text no. 7    
8.Epstein J, Burchell J, Emerton S, Le N, Silverman S. A clinical trial of bethanechol in patients with xerostomia after radiation therapy. A pilot study. Oral Surgery, Oral Medicine and Oral Pathology 1994;77:610-4.  Back to cited text no. 8    
9.Taylor SE. Efficacy and economic evaluation of pilocarpine in treating radiation-induced xerostomia. Expert Opin Pharmacother 2003; 4(9):1489-97.  Back to cited text no. 9    
10.Davies A. Salivary gland dysfunction. In : Davies A, Finlay I, editors. Oral Care in Advanced Disease. Oxford: Oxford University Press; 2005. p. 97-114.  Back to cited text no. 10    




 

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