Disease Related

PHYSOSTIGMINE

Physostigmine is a reversible inhibitor of the enzyme acetylcholinesterase, which increases the levels of acetylcholine at synapses. It is primarily used to treat anticholinergic toxicity, particularly from drugs like atropine or scopolamine. Additionally, it can be used in the management of myasthenia gravis. Due to its ability to cross the blood-brain barrier, physostigmine can also address central nervous system effects of anticholinergic overdose. Its effectiveness and rapid action make it a critical agent in emergency medicine.

Physostigmine is a cholinergic agent that inhibits the breakdown of acetylcholine (ACh) in the body, thereby increasing its levels and duration of action.

Chemical Structure:

  • Molecular Formula: C15H21N3O2
  • Chemical Name: (3aS,8aR)-1,2,3,3a,8,8a-Hexahydropyrrolo[2,3-b]indol-5-yl N-methylcarbamate

Pharmacological Effects:

  • Inhibits acetylcholinesterase, leading to:
    • Increased muscle contraction
    • Increased salivation and sweating
    • Pupil constriction (miosis)
    • Increased gastrointestinal motility and secretion
    • Urinary bladder contraction
    • Bronchoconstriction

Clinical Uses:

  • Treatment of:
    • Myasthenia gravis
    • Glaucoma (to reduce intraocular pressure)
    • Anticholinergic poisoning
    • Reversal of neuromuscular blockade
  • Diagnostic tool for:
    • Myasthenia gravis

Side Effects:

  • Nausea, vomiting, and diarrhea
  • Headache, dizziness, and weakness
  • Abdominal cramps and discomfort
  • Flushing, sweating, and hypersalivation
  • Bronchospasm and respiratory distress (rare)

Contraindications:

  • Asthma and other respiratory conditions
  • Peptic ulcer disease
  • Hyperthyroidism
  • Pregnancy and lactation
  • Hypotension and cardiac arrhythmias

Note: Physostigmine is a potent cholinergic agent and should be used with caution, under medical supervision.