Drug Class Description
Anticholinesterases.

Generic Name
Pyridostigmine - paralytic ileus

Drug Description
Each tablet contains 62.5mg pyridostigmine bromide (equivalent to 60.0mg of the base).

Presentation
Tablets for oral administration.White to off-white, round, biplanar, bevel-edged tablets imprinted with two break marks forming a cross on the other.

Indications
Myasthenia gravis, paralytic ileus and post-operative urinary retention.

Adult Dosage
Myasthenia gravisAdultsDoses of 30 to 120mg are given at intervals throughout the day when maximum strength is needed (for example, on rising and before mealtimes). The usual duration of action of a dose is 3 to 4 hours in the daytime but a longer effect (6 hours) is often obtained with a dose taken on retiring for bed.The total daily dose is usually in the range of 5 – 20 tablets but doses higher than these may be needed by some patients.ChildrenChildren under 6 years old should receive an initial dose of half a tablet (30mg) of Mestinon; children 6 – 12 years old should receive one tablet (60mg). Dosage should be increased gradually, in increments of 15 – 30mg daily, until maximum improvement is obtained. Total daily requirements are usually in the range to 30 – 360mg.The requirement for Mestinon is usually markedly decreased after thymectomy or when additional therapy (steroids, immunosuppressant drugs) is given.When relatively large doses of Mestinon are taken by myasthenic patients it may be necessary to give atropine or other anticholinergic drugs to counteract the muscarinic effects. It should be noted that the slower gastro-intestinal motility caused by these drugs may affect the absorption of Mestinon.In all patients the possibility of "cholinergic crisis", due to overdosage of Mestinon, and its differentiation from "myasthenic crisis", due to increased severity of the disease, must be borne in mind. Both types of crisis are manifested by increased muscle weakness, but whereas myasthenic crisis may require more intensive anticholinesterase treatment, cholinergic crisis calls for immediate discontinuation of this treatment and institution of appropriate supportive measures, including respiratory assistance.Other IndicationsAdultsThe usual dose is 1 to 4 tablets (60 – 240mg).Children15 – 60mg.The frequency of these doses may be varied according to the needs of the patient.ElderlyThere are no specific dosage recommendation for Mestinon in elderly patients.

Child Dosage
Myasthenia gravis - Children under 6 years old should receive an initial dose of half a tablet (30mg) of Mestinon; children 6 – 12 years old should receive one tablet (60mg). Dosage should be increased gradually, in increments of 15 – 30mg daily, until maximum improvement is obtained. Total daily requirements are usually in the range to 30 – 360mg.Other Indications - Children - 15 – 60mg. The frequency of these doses may be varied according to the needs of the patient.

Elderly Dosage
There are no specific dosage recommendation for Mestinon in elderly patients.

Contra Indications
Mestinon should not be given to patients with mechanical gastro-intestinal or urinary obstruction. Mestinon is contra-indicated in patients with known hypersensitivity to the drug and to bromides.

Special Precautions
Extreme caution is required when administering Mestinon to patients with bronchial asthma.Care should also be taken in patients with bradycardia, recent coronary occlusion, hypotension, vagotonia, peptic ulcer, epilepsy or Parkinsonism.There is no evidence to suggest that Mestinon has any special effects on the elderly. However, elderly patients may be more susceptible to dysrhythmias than the young adult.Mestinon is mainly excreted unchanged by the kidney, therefore lower doses may be required in patients with renal disease and treatment should be based on titration of drug dosage to effect.

Interactions
Antimuscarinics Atropine and Hyoscine antagonise the muscarinic effects of pyridostigmine bromide.Muscle RelaxantsPyridostigmine antagonises the effect of non-depolarising muscle relaxants (e.g. pancuronium and vecuronium). Pyridostigmine may prolong the effect of depolarising muscle relaxants (e.g. suxamethonium).

Adverse Reactions
These may include nausea and vomiting, increased salivation, diarrhoea and abdominal cramps.

Manufacturer
Valeant Pharmaceuticals Ltd

Drug Availability
(POM)

Updated
03 June 2009