Edrophonium
Tensilon
Short-acting acetylcholinesterase inhibitor
Reversible AChE inhibitor with the FASTEST onset (1–2 min) and SHORTEST duration (5–10 min) of the anticholinesterases. Quaternary structure → no CNS penetration. Largely historical; replaced by sugammadex in NMB reversal and by serologic AChR antibody testing in myasthenia diagnosis.
Indications
- •Diagnostic Tensilon test for myasthenia (historical)
- •Acute differentiation of myasthenic vs cholinergic crisis (historical)
- •Reversal of non-depolarizing NMB (rare; faster onset than neostigmine — paired with atropine)
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Tensilon test | 1–2 mg IV test dose; if no adverse effect, additional 8 mg IV; observe for transient strength improvement | — |
| NMB reversal (rare) | 0.5–1 mg/kg IV with atropine 7 mcg/kg (faster atropine onset matches edrophonium's) | — |
Pharmacokinetics
Onset 1–2 min IV (faster than neostigmine). Duration 5–10 min only. Renal excretion 75%.
Hemodynamic effects
Brief bradycardia + hypotension on rapid IV. Atropine pairing needed.
Respiratory effects
Brief bronchoconstriction.
Side effects
- !Bradycardia, asystole on rapid push
- !Increased secretions, bronchorrhea
- !GI cramping
- !Cholinergic crisis at high dose
Contraindications
- ×Mechanical GI/urinary obstruction
- ×Hypersensitivity
Clinical pearls
- ★ATROPINE PAIRING: edrophonium's fast onset means atropine (faster than glycopyrrolate) is the matched anticholinergic. The pairing logic: match the muscarinic-block onset to the AChE-inhibition onset.
- ★DIAGNOSTIC USE: AChR antibody serology has supplanted the Tensilon test. If you see edrophonium ordered for diagnosis in 2026, look for an explanation in the chart.
- ★SHORT DURATION = LIMITED REVERSAL UTILITY: 5–10 min reversal duration risks recurarization once edrophonium wears off and residual NMB redistributes from muscle. Sugammadex or higher-dose neostigmine preferred.
- ★AVAILABILITY: edrophonium has been intermittently unavailable in the US (manufacturer changes). Don't plan around it — keep neostigmine + sugammadex stocked.
Other drugs in Anticholinesterases
- Neostigmine
Reversibly inhibits AChE → ↑ACh at NMJ → outcompetes non-depolarizing relaxants. Co-administer antimuscarinic (glycopyrrolate or atropine) to block muscarinic side effects.
- Pyridostigmine
Reversibly inhibits acetylcholinesterase → ↑acetylcholine at the neuromuscular junction. Quaternary ammonium → does NOT cross BBB → no CNS effects. Longer-acting than neostigmine; mainstay of chronic myasthenia gravis treatment.
- Physostigmine
Reversible AChE inhibitor with TERTIARY amine structure → CROSSES blood-brain barrier (unlike neostigmine, pyridostigmine, edrophonium). The only AChE inhibitor that treats CENTRAL anticholinergic syndrome.
Browse all classes: /reference/drugs
Suggested reading
- •Stoelting & Hines, Pharmacology & Physiology in Anesthetic Practice, 6e
- •Miller's Anesthesia, 9e
- •FDA package insert
