Edrophonium (Tensilon, Reversol, Enlon)

Category:

  • Cholinergic Muscle Stimulant

Description:

  • Facilitates transmission of impulses across myoneural junction by inhibiting destruction of acetycholine by cholinesterase

Indications:

  • Curare antidote

  • Diagnosis of myasthenia gravis

  • Differentiate between cholinergic crisis and myasthenia gravis crisis

  • Evaluation of treatment requirements in myasthenia gravis

Contraindications:

  • Mechanical, intestinal, and urinary obstructions

Precautions:

  • Pregnancy category C; ionized at physiologic pH, not expected to cross placental barrier or excreted in breast milk

  • May cause premature labor

  • Seizure disorders, bronchial asthma, recent coronary occlusion, hyperthyroidism

  • Dysrhythmias, peptic ulcer, megacolon, poor GI motility, bradycardia, hypotension

Adverse Reactions (Side Effects):

  • CNS: dizziness, drowsiness, headache, incoordination, seizures, sweating, paralysis, weakness, loss of consciousness

  • CV: AV block, bradycardia, cardiac arrest, dysrhythmias, , syncope, hypotension, tachycardia

  • EENT: blurred vision, lacrimation, miosis, visual changes

  • GI: cramps, diarrhea, dysphagia, increased peristalsis, increased salivary and gastric secretions, nausea, vomiting

  • GU: Frequency, incontinence, urgency

  • MS: arthralgia, fasciculations, muscle cramps and spasms, weakness

  • RESP: bronchospasm, dyspnea, laryngospasm, respiratory arrest, respiratory depression, increased tracheobronchial secretions

  • SKIN: rash, urticaria

Dosage:

Administered IV/IM

  • Adult: 

    • Diagnosis of myasthenia gravis: 

      • IV 1-2mg over 15-30 seconds, then 8mg if no response

      • IM 10mg; if cholinergic reaction occurs, retest after hour with 2mg IM

    • Evaluation of treatment requirements in myasthenia gravis: 

      • IV 1-2mg 1 hour after PO dose of anticholinesterase

      • if strength improves, an increase in neostigmine or pyridostigmine is indicated

    • Differentiation of myasthenic crisis from cholinergic crisis: 

      • IV 1mg, if no response in 1 minute, may repeat

      • myasthenic crisis clear improvement in respiration

      • cholinergic crisis increased oropharyngeal secretions and further weakening of respiratory muscles (intubation and controlled respiration may be required)

    • Curare antagonist: 

      • IV 10mg over 30-45 seconds; may repeat; not to exceed 40mg

  • Child: 

    • Diagnosis of myasthenia gravis: 

      • IV 0.04 mg/kg given over 1 minute followed by 0.16 mg/kg given within 45 seconds if no response

      • >34 kg IM 2mg

      • <34 kg IM 1mg

      • infant 0.1mg, followed by 0.4mg if no response, not to exceed 0.5mg

    • Evaluation of treatment requirements in myasthenia gravis: 

      • IV 0.04 mg/kg given 1 hour after PO intake of drug being used in treatment

      • if strength improves, an increase in neostigmine or pyridostigmine is indicated

 
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