Patho Pharm Drug List - Cholinesterase Inhibitors + Myasthenia Gravis

Pyridostigmine [Mestinon]

Action: reversible cholinesterase inhibitor; increases acetylcholine at neuromuscular junctions, main use: myasthenia gravis; also reverses nondepolarizing blockade
major adverse effects: excess muscarinic stimulation; at toxic levels can worsen weakness and cause neruomuscular blockade
nursing priorities: assess swallowing, breathing, and muscle strength, give on schedule; stropine treats muscarinic toxicity

Neostigmine [Bloxiverz/Prostigmin]

Action: reversible cholinesterase inhibitor used for myasthenia gravis and reversal of nondepolarizing neuromuscular blockade
major adverse effects: bradycardia, bronchoconstrction, urinary urgency, increased secretions/GI motility, miosis, excessive dose may worsen weakness
nursing priorities: monitor HR, breathing, secretions, swallowing and muscle strength, may be paired with atropine

Edrophonium

Action: very short-acting cholinesterase inhibitor historically used as a challenge to distinguish myasthenic from cholinergic crisis
major adverse effects: may intensify cholinergic symptoms, bradycardia, and weakness
nursing priorities: improvement suggests myasthenic crisis; worsening with muscarinic findings suggests cholinergic crisis

Echothiophate

action: irreversible cholinesterase inhibitor; rare clinical application is glaucoma, organophosphate-type agents can cause cholinergic crisis
major adverse effects: profuse secretions, bronchospasm, bradycardia, diarrhea, miosis, weakness/paralysis, seizures, respiratory failure
nursing priorities: prioritize airway and ventilation, give pralidoxime early + atropine, diazepam for seizures

Pralidoxime [Protopam]

action: specific antidote for irreversible cholinesterase inhibitor/organophosphate poisoning; reactivates cholinesterase when given early
major adverse effects: effectiveness falls as time passes after exposure (“aging”)
nursing priorities: give early with atropine and respiratory support

Myasthenic crisis (crisis differentiation)

action: too little effective acetylcholine activity from under-medication or disease exacerbation
major adverse effects: severe skeletal muscle weakness, dysphagia, ptosis, respiratoyr muscle failure; no prominent muscarinic excess
nursing priorities: support airway/ventilations, anticipate cholinesterase-inhibitor therapy

Cholinergic crisis (crisis differentiation)

action: too much cholinesterase inhibitor → excess acetylcholine and depolarizing weakness
major adverse effects: severe weakness/paralysis PLUS salivation, sweating, diarrhea, bradycardia, bronchial secretions/miosis
nursing priorities: hold the causative drug, support ventilation, and give atropine