What are the uses of Pyridostigmine (Mestinon)?

From the Guidelines

Pyridostigmine is primarily used to treat myasthenia gravis, with a recommended dosing of 30-600 mg daily, and may also be used in the management of immune-related adverse events, particularly those with myasthenic symptoms, as stated in the 2022 ESMO clinical practice guideline 1.

Uses of Pyridostigmine

• Treatment of myasthenia gravis, a neuromuscular disorder characterized by muscle weakness and fatigue
• Management of immune-related adverse events, particularly those with myasthenic symptoms
• Pretreatment against nerve agent poisoning in military settings
• Off-label uses for treating postural orthostatic tachycardia syndrome (POTS) and managing some autonomic disorders

Dosage and Administration

• Typical dosing for adults with myasthenia gravis: 30-60 mg orally every 3-4 hours while awake, adjusted based on symptom control
• Dosing for immune-related adverse events: 30 mg orally up to 600 mg daily, as needed
• Intravenous application: 1 mg i.v. corresponds to 30 mg oral pyridostigmine

Side Effects and Monitoring

• Common side effects: gastrointestinal symptoms, increased salivation and sweating
• Patients should be monitored for cholinergic crisis, which can occur with overdosage and presents with severe muscle weakness, respiratory difficulties, and excessive secretions
• The medication should be taken consistently to maintain therapeutic levels and may require dose adjustments based on individual response and tolerance

Recent Guidelines and Recommendations

• The 2022 ESMO clinical practice guideline recommends pyridostigmine as a treatment option for immune-related adverse events with myasthenic symptoms 1
• The 2024 adult strabismus preferred practice pattern recommends pyridostigmine as the first line of treatment for myasthenia gravis, but notes that about half of patients with strabismus-associated myasthenia show minimal response 1

From the FDA Drug Label

Pyridostigmine bromide is useful in the treatment of myasthenia gravis. The main use of pyridostigmine is in the treatment of myasthenia gravis 2.

• Key uses: treatment of myasthenia gravis It works by inhibiting the destruction of acetylcholine by cholinesterase, permitting freer transmission of nerve impulses across the neuromuscular junction 2.

From the Research

Pyridostigmine Uses

• Pyridostigmine is used in the symptomatic treatment of myasthenia gravis (MG) 3, 4, 5, 6, 7
• It is an anticholinesterase agent that has been used for over 50 years to treat MG 6
• Pyridostigmine 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 6

Efficacy and Side Effects

• Patients reported a median effectiveness of 60 and net benefit of 65 when using pyridostigmine 3
• Common side effects of pyridostigmine include flatulence, urinary urgency, muscle cramps, blurred vision, and hyperhidrosis 3
• Diarrhea, abdominal cramps, and muscle twitching are also reported as reasons to discontinue pyridostigmine 3

Administration and Dosage

• The sustained-release dosage form of pyridostigmine (SR-Pyr) can reduce the number of daily doses and improve the total quantified myasthenia gravis (QMG) score 5
• Continuing pyridostigmine till the day of surgery or omitting it on the night before surgery can provide variable results with regards to the effect of vecuronium 4

Historical Aspects

• Pyridostigmine bromide was unsuccessful in its "pioneering trials" to treat a series of MG patients, but it has become an indispensable anticholinesterase agent used worldwide to treat patients with MG 7