Edrophonium Chloride

 Action Facilitates myoneural junction impulse transmission by inhibiting acetylcholine destruction by cholinesterase.

 Indications Differential diagnosis of myasthenia gravis; adjunct in evaluating treatment of myasthenia gravis; evaluation of emergency treatment of myasthenic crises; reversal of neuromuscular blockade by curare gallamine or tubocurarine; treatment of respiratory depression due to curare overdose.

 Contraindications Hypersensitivity to anticholinesterases; mechanical intestinal and urinary obstruction.

 Route/Dosage

Diagnosis of Myasthenia Gravis

ADULTS: IM/IV 10 mg. CHILDREN > 34 KG: IV 2 mg. If no response after 45 sec, may titrate up to 10 mg in increments of 1 mg q 30–45 sec. or IM 5 mg as single dose. CHILDREN < 34 KG: IV 1 mg. If no response after 45 sec, may titrate up to 5 mg in increments of 1 mg q 30–45 sec or IM 2 mg as single dose. INFANTS: IV 0.5 mg.

Evaluation of Myasthenia Gravis Treatment

ADULTS: IV 1 to 2 mg 1 hr after ingestion of treatment drug.

Crisis Test

ADULTS: IV When respiration is adequate, give 1 mg initially. If after 1 min patient is not further impaired, give additional 1 mg.

Curare Antagonist

ADULTS: IV 10 mg over 30–45 sec. Repeat prn up to maximum total dose of 40 mg.

 Interactions

Corticosteroids: May antagonize anticholinesterases in myasthenia gravis, producing profound muscular depression. Succinylcholine: Neuromuscular blockade produced by succinylcholine may be either prolonged or antagonized.

 Lab Test Interferences None well documented

 Adverse Reactions

CV: Arrhythmia (especially bradycardia); hypotension; tachycardia; atrioventricular block; nodal rhythm; non-specific ECG changes; cardiac arrest; syncope. CNS: Convulsions; dysarthria; dysphonia; dizziness; loss of consciousness; drowsiness; headache. DERM: Rash; urticaria; flushing. EENT: Lacrimation; miosis; spasm of accommodation; diplopia; conjunctival hyperemia; visual changes. GI: Increased salivary, gastric and intestinal secretions; nausea; vomiting; dysphagia; increased peristalsis; diarrhea; abdominal cramps; flatulence. GU: Urinary urgency, frequency and incontinence. RESP: Increased tracheobronchial secretions; laryngospasm; bronchiolar constriction; respiratory paralysis; dyspnea; respiratory depression; respiratory arrest; bronchospasm. OTHER: Allergy and anaphylaxis; weakness; fasciculations; muscle cramps and spasms; arthralgia; diaphoresis.

 Precautions

Pregnancy: Pregnancy category undetermined. Lactation: Undetermined. Special risk patients: Use with caution in patients with bronchial asthma, epilepsy, bradycardia, recent coronary occlusion, vagotonia, hyperthyroidism, cardiac arrhythmias or peptic ulcer. Anticholinesterase insensitivity: May develop.

 Administration/Storage

• Given IM or IV only.
• Store at room temperature.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies.
• Assess neuromuscular status before and frequently during therapy.
• Obtain baseline ECG and vital signs before therapy and monitor throughout administration.
• If ECG changes develop (supraventricular tachycardia), notify physician immediately.
• Take seizure precautions.
• Keep atropine available in syringe as antidote.
• Have respiratory support equipment available.

 Patient/Family Education

• Teach patient and family name, desired action, method of administration and potential side effects of edrophonium.
• Inform patient that effects of medication last up to 30 min after IM administration.
• Show patient and family how to assess and record changes in muscle strength.
• Advise patient that urinary urgency and frequency and increased GI motility and secretion will occur and should be reported to physician.