Drugs Used in Myasthenia Gravis (MG)

Drugs for Myasthenia Gravis include cholinesterase inhibitors, immunosuppressants, and corticosteroids to improve muscle strength.

Pharmacological Goal:

• To increase acetylcholine availability at the neuromuscular junction and/or suppress the autoimmune response.

Main Classes of Drugs:

1. Cholinesterase Inhibitors (First-line therapy):

   • Mechanism:
     • Inhibit the enzyme acetylcholinesterase, increasing ACh levels at the neuromuscular junction.
   • Examples:
     • Pyridostigmine (preferred)
     • Neostigmine
   • Adverse Effects:
     • Muscarinic effects: diarrhea, salivation, sweating, bradycardia
     • These effects can be managed with antimuscarinic drugs (e.g., atropine)

2. Immunosuppressants:

   • Used in moderate to severe or refractory cases.
   • Examples:
     • Corticosteroids: Prednisolone
     • Other immunosuppressants: Azathioprine, Mycophenolate mofetil, Cyclosporine, Tacrolimus

3. Monoclonal Antibodies:

   • Used for refractory generalized myasthenia gravis.
   • Example: Eculizumab (targets complement protein C5)

4. Plasmapheresis / Intravenous Immunoglobulin (IVIG):

   • Used in acute exacerbations or myasthenic crisis
   • Temporarily remove or neutralize circulating antibodies

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