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Pyridostigmine Bromide


Pronunciation: pihr-id-oh-STIG-meen BROE-mide
Class: Anticholinesterase muscle stimulant

Trade Names

- Tablets 60 mg
- Tablets, extended-release 180 mg
- Syrup 60 mg/5 mL

Mestinon-SR (Canada)


Facilitates myoneural junction impulse transmission by inhibiting acetylcholine destruction by cholinesterase.

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Primarily excreted unchanged by the kidney.

Indications and Usage

Treatment of myasthenia gravis.


Mechanical intestinal or urinary obstruction; hypersensitivity to anticholinesterase agents.

Dosage and Administration

Adults Syrup/Conventional tablet

PO Average dose is ten 5 mL tsp (60 mg/5 mL) daily or ten 60 mg tablets spaced to provide max relief when max strength is needed (range is usually 1 to 25 tablets or tsp/day).

ER tablets

PO One to 3 tablets, once or twice daily with at least 6 h between doses. For optimum control, it may be necessary to use the conventional tablets or syrup in conjunction with the ER tablets.

General Advice

  • Administer without regard to meals. Administer with food if GI upset occurs.
  • Do not chew or crush ER tablet; swallow whole.
  • Because of the hygroscopic nature of the ER tablets, mottling may occur. This does not affect their efficacy.


Store at 59° to 86°F.

Drug Interactions


May mask signs of overdosage, leading to inadvertent induction of cholinergic crisis.


The therapeutic effects of pyridostigmine may be antagonized.


Neuromuscular blockade produced by succinylcholine may be prolonged or antagonized.

Adverse Reactions


Nausea; vomiting; diarrhea; abdominal cramps; increased peristalsis; increased salivation.


Muscle cramps and fasciculation; weakness.


Increased bronchial secretions, increased sweating, miosis, skin rash.



Category C .


Excreted in breast milk.

Renal Function

Lower doses may be required.

Bronchial asthma

Use with caution.

Cholinergic crisis

Observe patients closely for cholinergic reactions. May be difficult to distinguish from myasthenic crisis. Differentiation is important because increasing the dose of pyridostigmine or other drugs of this class may have grave consequences in patients in cholinergic crisis.



Cholinergic crisis, characterized by increasing muscle weakness (including respiratory paralysis and death).

Patient Information

  • Advise patient that dose and frequency of administration may be adjusted to achieve max benefit.
  • Advise patient to take exactly as prescribed and not to change the dose or stop taking unless advised by health care provider.
  • Advise patient to take prescribed dose without regard to meals but to take with food if upset stomach occurs.
  • Instruct patient to contact health care provider immediately if any of the following occur: worsening muscle weakness, difficulty breathing, slow heart rate, dizziness, fainting.

Copyright © 2009 Wolters Kluwer Health.