TENSILON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TENSILON (TENSILON).
Acetylcholinesterase inhibitor; increases acetylcholine concentration at cholinergic synapses by inhibiting hydrolysis of acetylcholine.
| Metabolism | Primarily hydrolyzed by plasma cholinesterases and also metabolized in the liver via microsomal enzymes. |
| Excretion | Renal: >90% unchanged via tubular secretion and glomerular filtration; biliary/fecal: <5%. |
| Half-life | Terminal elimination half-life is 1.5–2 hours in adults; prolonged in renal impairment. |
| Protein binding | Minimal, <10% bound to plasma albumin. |
| Volume of Distribution | 0.3–0.5 L/kg, reflecting distribution primarily in extracellular fluid. |
| Bioavailability | Oral route not clinically relevant due to rapid hydrolysis; IV: 100%; IM: approximately 80–100%. |
| Onset of Action | IV: 30–60 seconds; IM: 2–5 minutes. |
| Duration of Action | IV: 5–15 minutes; IM: 10–30 minutes. Short duration due to rapid hydrolysis by plasma cholinesterases. |
2-10 mg intravenously over 15-30 seconds, repeated every 2-5 minutes as needed for diagnosis of myasthenia gravis, up to a total of 10 mg; for reversal of neuromuscular blockade: 10-20 mg intravenously slowly after atropine.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment guidelines; use with caution in renal impairment due to potential for prolonged effect. |
| Liver impairment | No specific dose adjustment guidelines; use with caution in severe hepatic impairment due to reduced clearance. |
| Pediatric use | Diagnosis of myasthenia gravis: 0.2 mg/kg intravenously, up to 10 mg per dose; for reversal of neuromuscular blockade: 0.5-1 mg/kg intravenously after atropine. |
| Geriatric use | No specific dose adjustment; use lower initial doses and titrate due to increased sensitivity and risk of bradycardia and hypotension. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TENSILON (TENSILON).
| Breastfeeding | Excretion in human milk unknown. Caution advised. No M/P ratio available. |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: Limited human data; no structural anomalies reported in animal studies with high doses. Second and third trimesters: May cause fetal respiratory depression and bradycardia due to anticholinesterase activity; use only if clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to edrophonium; mechanical intestinal or urinary obstruction; patients receiving depolarizing neuromuscular blockers (e.g., succinylcholine).
| Precautions | May cause bradycardia, hypotension, and bronchoconstriction; use caution in patients with asthma, cardiac arrhythmias, or peptic ulcer disease; have atropine and respiratory support available. |
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| Monitor fetal heart rate and uterine activity during administration. Assess for signs of cholinergic crisis (e.g., excessive salivation, bradycardia) in mother and neonate. |
| Fertility Effects | No specific data on fertility effects in humans. In animal studies, no adverse effects on fertility at therapeutic doses. |