Effect of Pyridostigmine (Mestinon) on Muscle Strength in Myasthenia Gravis

Effect of Pyridostigmine (Mestinon) on Muscle Strength in Myasthenia Gravis

A randomized, placebo-controlled, double-blinded cross-over study evaluating and quantifying the effect of pyridostigmine on muscle strength and symptoms in Myasthenia Gravis (MG)

The study aims to evaluate and quantify the effect of pyridostigmine on symptoms and muscle strength in newly-diagnosed patients and patients on stable medication.

Pyridostigmine treatment is initiated in the vast majority of MG patients. No studies have quantified the effect in a randomized trial, and no studies have examined the potential difference in effect in newly diagnosed patients as compared to patients on stable, antimyasthenic medications.

The study will investigate the effect in two groups

1. Newly diagnosed, treatment-naive patients.
2. MG patients on stable antimyasthenic medication.

Inclusion Criteria:

• MG verified by a) anti-body, or b) single-fiber EMG and/or decrement on ENG.

Exclusion Criteria:

• Anti-MuSK
• Known cardio-pulmonary disease
• Known neuropathy
• Known myopathy
• Known malignant disease
• Pregnancy or breastfeeding
• Mechanic ileus, urinary tract obstruction, peritonitis

De-novo MG Eligibility Criteria

• MG diagnosis < 2 months, no prior antimyasthenic medications

Chronic MG Eligibility Criteria

• MG diagnosis > 1 year, and stable pyridostigmine dosis