Adult: Initially, 10 mg. If cholinergic reaction occurs, administer 2 mg after 30 min to rule out false-negative reactions. Child: ≤34 kg: 2 mg; >34 kg: 5 mg.
Intravenous Diagnosis of myasthenia gravis
Adult: Initially, 2 mg test dose over 15-30 seconds. If no cholinergic reaction after 45 seconds, administer 8 mg. If reaction occurs, discontinue testing and then administer IV atropine. Test may be repeated after 30 min, if necessary. Child: ≤34 kg: 1 mg test dose; >34 kg: 2 mg test dose. If no reaction after 45 seconds, 1 mg may be given every 30-45 seconds up to max cumulative dose of 5 mg (≤34 kg) or 10 mg (>34 kg). Infants: 0.5 mg.
Intravenous Anticholinesterase therapy evaluation
Adult: 1-2 mg given 1 hr after oral anticholinesterase dose. Controlled patients show adequate response; undertreated patients show myasthenic response; and overtreated patients show cholinergic response.
Intravenous Cholinergic and myasthenic crisis differentiation
Adult: 1 mg, may repeat after 1 min.
Intravenous Reversal of neuromuscular blockade
Adult: Given to reverse blockade from nondepolarising agents: 10 mg given slowly over 30-45 seconds, may repeat every 5-10 min as necessary. Max total: 40 mg. Alternatively, 0.5-1 mg/kg.
Contraindications
Mechanical obstruction of GI or genitourinary tract.
Special Precautions
Patient w/ bronchial asthma, cardiac arrhythmia (e.g. bradyarrhythmia). Not indicated to reverse non-depolarising neuromuscular blockade in patients w/ myasthenia gravis. Childn. Pregnancy and lactation.
Monitor pre- and post-injection strength, heart and resp rate, and BP.
Overdosage
Symptoms: Cholinergic crisis manifesting as nausea, vomiting, diarrhoea, excessive sweating, increased bronchial and salivary secretions, bradycardia or tachycardia, cardiospasm, hypotension, blurred vision, weakness, incoordination, muscle cramps, fasciculation, paralysis, bronchospasm, airway obstruction, resp paralysis, pulmonary oedema, cardiac arrest. Management: Administer 0.4-0.5 mg IV atropine, repeated every 3-10 min to control cholinergic symptoms. Maintain adequate respiration by assuring an open airway (through tracheostomy, bronchial aspiration, and postural drainage) and providing assisted respiration w/ oxygen. Monitor cardiac function until complete stabilisation. In case of airway obstruction due to bronchial secretions, administer up to 1.2 mg IV atropine, repeated every 20 min until secretions are controlled.
Drug Interactions
Antagonised muscarinic effects w/ atropine. May cause an increased sensitivity of the heart to edrophonium when given w/ digitalis. May prolong the phase 1 blockade of depolarising muscle relaxants (e.g. suxamethonium, decamethonium). May antagonise the effects of nondepolarising muscle relaxants (e.g. atracurium, pancuronium, vecuronium, tubocurarine, metocurine).
Action
Description: Mechanism of Action: Edrophonium chloride is a synthetic quaternary ammonium cholinergic agent. It reversibly inhibits the hydrolysis of acetylcholine by binding to the anionic site of acetylcholinesterase, thereby causing accumulation of acetylcholine. This results in increased cholinergic responses including increased tonus of skeletal and intestinal muscles, bronchial and ureteral constriction, miosis, bradycardia, and increased sweat and salivary secretions. Onset: 30-60 seconds (IV); 2-10 min (IM). Duration: 5-10 min (IV); 5-30 min (IM). Pharmacokinetics: Distribution: Volume of distribution: 0.9 ± 0.13 L/kg. Excretion: Mainly via urine (67%). Elimination half-life: 126 ± 59 min.
Chemical Structure
Edrophonium chloride Source: National Center for Biotechnology Information. PubChem Database. Edrophonium chloride, CID=8307, https://pubchem.ncbi.nlm.nih.gov/compound/Edrophonium-chloride (accessed on Jan. 21, 2020)
Anon. Edrophonium. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 04/05/2017.Buckingham R (ed). Edrophonium Chloride. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 04/05/2017.Enlon Injection, Solution (Mylan Institutional LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 04/05/2017.McEvoy GK, Snow EK, Miller J et al (eds). Edrophonium Chloride. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 04/05/2017.
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