Edrophonium Chloride
Edrophonium chloride is a **short-acting, parenteral anticholinesterase agent** primarily utilized in veterinary medicine for the presumptive diagnosis of **myasthenia gravis (MG)** via the 'Tensilon Test'. While it can also be used to reverse non-depolarizing neuromuscular blocking agents or treat specific supraventricular tachycardias (SVTs), its extremely short duration of action often makes longer-acting alternatives (like neostigmine or pyridostigmine) more practical for these secondary indications. > **Clinical Pearl:** The 'Tensilon Test' has a fair percentage of false-positives and false-negatives. It is best used as a rapid, presumptive diagnostic tool while awaiting results from more specific and sensitive assays, such as the acetylcholine receptor (AChR) antibody test.
Mecanismo: Edrophonium acts as a rapid, reversible inhibitor of the enzyme **acetylcholinesterase**. **Mechanism of Action:** Edrophonium briefly attaches to **acetylcholinesterase** → inhibits its hydrolytic activity → **acetylcholine** accumulates in the synaptic cleft → prolonged and increased stimulation of nicotinic and muscarinic receptors. In patients with myasthenia gravis, the sudden surge of acetylcholine temporarily overcomes the autoimmune blockade/destruction of nicotinic receptors at the neuromuscular junction, leading to a rapid (but transient) return of muscle strength. Systemically, acetylcholine accumulation also causes parasympathomimetic effects including miosis, increased intestinal muscle tone, bronchoconstriction, salivation, and bradycardia.
Dosificación por especie
- Presumptive diagnosis of myasthenia gravis (MG) · 0.25 to 0.5 mg (total dose) · IV · Once · Patient is gently exercised until fatigued. Place indwelling catheter. Have atropine drawn up (0.02-0.04 mg/kg IV) in case cholinergic signs develop. Flush catheter with sterile saline, then immediately lightly exercise or encourage to rise.
- Presumptive diagnosis of myasthenia gravis (MG) · 0.1 mg/kg · IV · Once · Pre-treat with atropine (0.02-0.04 mg/kg IM or SC). In affected animals, paresis should resolve within one minute and effects should last for up to 15 minutes.
- Presumptive diagnosis of myasthenia gravis (MG) · 0.1-0.2 mg/kg · IV · Once · Patient is gently exercised until fatigued. Place indwelling catheter. Have atropine drawn up (0.02-0.04 mg/kg IV) in case cholinergic signs develop. Flush catheter with sterile saline, then immediately lightly exercise or encourage to rise.
- Presumptive diagnosis of myasthenia gravis (MG) · 1-10 mg (total dose) · IV · Once · Presumptive positive test results in transient improvement in clinical weakness.
- Presumptive diagnosis of myasthenia gravis (MG) · 0.1-0.2 mg/kg · IV · Once · Have atropine and endotracheal tube readily available in case of overdose.
- Presumptive diagnosis of myasthenia gravis (MG) · 0.1 mg/kg · IV · Once · Pre-treat with atropine (0.02-0.04 mg/kg IM or SC). In affected animals, paresis should resolve within one minute and effects should last for up to 15 minutes.
Las dosis son una referencia clínica para veterinarios colegiados. Confirme siempre con la ficha técnica vigente y el paciente individual.
Vías de administración
Contraindicaciones
- Bronchial asthma
- Mechanical urinary tract obstruction
- Mechanical intestinal tract obstruction
- Known hypersensitivity to the drug
Efectos adversos
- Urination
- Lacrimation
- Vomiting
- Defecation
- Bradycardia
- Bronchospasm
- Salivation
Interacciones farmacológicas
- Atropine · Antagonizes the muscarinic effects of edrophonium. Concurrent use should be done cautiously as atropine can mask the early clinical signs of a cholinergic crisis.
- Dexpanthenol · Theoretically may have additive cholinergic effects when used with edrophonium.
- Digoxin · Edrophonium's cardiac effects may be increased; excessive slowing of heart rate (bradycardia) may occur.
- Depolarizing Muscle Relaxants (e.g., succinylcholine, decamethonium) · Edrophonium may prolong the Phase I block of these agents.
- Non-depolarizing Muscle Relaxants (e.g., pancuronium, tubocurarine, vecuronium, atracurium) · Edrophonium antagonizes the neuromuscular blocking actions of these agents.
Monitorización
- Cholinergic adverse effects (heart rate, respiratory rate/effort, salivation)
- Improvement of paresis (for 1-15 minutes) for presumptive diagnosis of myasthenia gravis
Sobredosis
Overdosage of edrophonium may induce a **cholinergic crisis**. **Clinical Signs of Toxicity (SLUDGE syndrome and beyond):** - **GI:** Nausea, vomiting, diarrhea, salivation - **Respiratory:** Increased bronchial secretions, bronchospasm, pulmonary edema, respiratory paralysis - **Ophthalmic:** Miosis, blurred vision, lacrimation - **Cardiovascular:** Bradycardia or tachycardia, cardiospasm, hypotension, cardiac arrest - **Musculoskeletal:** Muscle cramps, profound weakness, sweating (in animals with sweat glands) > **Treatment:** Consists of immediate respiratory and cardiac supportive therapy. Administer **atropine** IV to counteract severe muscarinic effects.
La referencia de fármacos de VetSheet está destinada a veterinarios colegiados como apoyo a la decisión clínica, no sustituye el juicio profesional ni la ficha técnica vigente del fabricante.