Pyridostigmine Bromide is indicated in:

• Myasthenia gravis
• Paralytic ileus
• Postoperative urinary retention

Pyridostigmine is an orally active cholinesterase inhibitor. It inhibits acetylcholinesterase, thereby preventing the breakdown of acetylcholine and enhancing neuromuscular transmission at the neuromuscular junction. Pyridostigmine is an analog of neostigmine but differs in clinically important aspects. It has a longer duration of action and produces fewer gastrointestinal side effects compared to neostigmine.

Adults: Doses of 60 to 120 mg (1 or 2 tablets) by mouth 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 three to four hours in the daytime but a longer effect (six 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 some patients may require doses higher than these.

Newborn Infants: The dosage requirements of Pyridostigmine range from 5-10 mg orally every four hours, given 30-60 minutes before feeding. Treatment is not usually required beyond eight weeks of age except in the rare conditions of congenital and familial infantile myasthenia.

Older Children: Children under 6 years old should receive an initial dose of half a tablet (30 mg) of Pyridostigmine, children 6-12 years old should receive one tablet (60 mg). Dosage should be increased gradually, in increments of 15-30 mg daily, until maximum improvement is obtained. Total daily requirements are usually in the range of 30-360 mg by mouth.

A potential interaction may occur between pyridostigmine bromide and the antimalarial drug mefloquine due to possible additive effects on the gastrointestinal tract. Theoretically, drugs such as dexpanthenol, which are converted in vivo to pantothenic acid, may also enhance cholinergic activity by increasing acetylcholine production when used with pyridostigmine.

Pyridostigmine is contraindicated in mechanical intestinal or urinary obstruction. Caution is required in patients with bronchial asthma. Care should be taken when using atropine to counteract adverse effects.

Side effects are mainly dose-related and include muscarinic and nicotinic effects. Muscarinic effects include nausea, vomiting, diarrhea, abdominal cramps, increased salivation, increased bronchial secretions, miosis, and sweating. Nicotinic effects include muscle cramps, fasciculations, and muscle weakness. Muscarinic effects may be counteracted by atropine, although caution is required. Skin rash may occur rarely and usually resolves after discontinuation.

The safety of pyridostigmine during pregnancy and lactation has not been established.

Pyridostigmine is primarily excreted unchanged via the kidneys; therefore, lower doses may be required in patients with renal impairment. Dosage should be carefully adjusted based on clinical response.

Drugs used in Myasthenia Gravis

Store in a cool, dry place, protected from light. Keep out of reach of children.