What is the use of Pyridostigmine (Mestinon)?

From the Guidelines

Pyridostigmine is primarily used to treat myasthenia gravis, a neuromuscular disorder characterized by muscle weakness, with a typical starting dose of 30-60 mg orally three to four times daily, as supported by the most recent evidence 1.

Key Points

• Pyridostigmine works as a cholinesterase inhibitor, preventing the breakdown of acetylcholine at neuromuscular junctions, which improves muscle strength by enhancing nerve impulse transmission to muscles.
• The medication should be taken with food to minimize gastrointestinal side effects such as nausea, vomiting, diarrhea, and abdominal cramps.
• Patients should maintain consistent timing between doses for optimal symptom control.
• Pyridostigmine is also occasionally used for other conditions including postural orthostatic tachycardia syndrome (POTS) and as protection against certain nerve agents.
• Patients should be monitored for signs of overdose (cholinergic crisis) including excessive sweating, increased salivation, and severe muscle weakness, which require immediate medical attention.

Dosage and Administration

• The typical starting dose is 30-60 mg orally three to four times daily, with dosing adjusted based on symptom control.
• For myasthenia gravis, total daily doses usually range from 180-540 mg, divided throughout the day.
• In cases of immune-related adverse events, pyridostigmine starting from 30 mg orally up to 600 mg daily may be used in case of myasthenic symptoms 1.

Special Considerations

• Pyridostigmine may be discontinued or withheld in case of intubation.
• Timely consultation of a neurologist is essential in managing myasthenia gravis and other neurological conditions.
• Corticosteroids, such as prednisone, may be administered in conjunction with pyridostigmine to manage symptoms 1.
• In severe cases, intravenous immunoglobulin (IVIG) or plasmapheresis may be considered as additional treatment options 1.

From the FDA Drug Label

Pyridostigmine bromide is useful in the treatment of myasthenia gravis. The use of Pyridostigmine (Mestinon) is for the treatment of myasthenia gravis 2.

• The main indication is to improve muscle strength in patients with this condition.
• Key use: Management of myasthenia gravis symptoms.

From the Research

Use of Pyridostigmine (Mestinon)

• Pyridostigmine is used in the symptomatic treatment of myasthenia gravis (MG) 3, 4, 5.
• It is an acetylcholinesterase inhibitor that has been used for over 50 years to treat MG 4, 5.
• Pyridostigmine is generally considered safe and is suitable as a long-term treatment in patients with generalized non-progressive milder disease, and as an adjunctive therapy in patients with severe disease who are also receiving immunotherapy 5.

Efficacy and Side Effects

• Studies have shown that pyridostigmine is effective in improving the symptoms of MG, with patients reporting a median effectiveness of 60 and a net benefit of 65 3.
• However, pyridostigmine can cause side effects, with the most frequently reported side effects being flatulence, urinary urgency, muscle cramps, blurred vision, and hyperhidrosis 3.
• The sustained-release dosage form of pyridostigmine has been shown to improve the quality of life parameters and reduce the number of daily doses 4.

Administration and Interaction with Other Medications

• Pyridostigmine can be administered orally, and the sustained-release dosage form is available in some countries 4.
• The use of pyridostigmine can affect the requirement of other medications, such as vecuronium, in patients with MG 6.
• Omission of the pyridostigmine dose on the day of surgery can predispose patients with MG to respiratory discomfort and sensitivity to vecuronium, while continued administration can prolong the onset time of vecuronium 6.