indication

For the differential diagnosis of myasthenia gravis and as an adjunct in the evaluation of treatment requirements in this disease. It may also be used for evaluating emergency treatment in myasthenic crises.

pharmacology

Edrophonium is a short and rapid-acting anticholinesterase drug. Its effect is manifest within 30 to 60 seconds after injection and lasts an average of 10 minutes. Edrophonium's pharmacologic action is due primarily to the inhibition or inactivation of acetylcholinesterase at sites of cholinergic transmission. Nicotinic acetylcholine (nAChR)receptors are found throughout the body, especially on muscle. Stimulation of these receptors causes to muscle contraction. In myasthenia gravis the body's immune system destroys many of the nicotinic acetylcholine receptors, so that the muscle becomes less responsive to nervous stimulation. Edrophonium chloride increases the amount of acetylcholine at the nerve endings. Increased levels of acetylcholine allow the remaining receptors to function more efficiently.

mechanism of action

Edrophonium works by prolonging the action acetylcholine, which is found naturally in the body. It does this by inhibiting the action of the enzyme acetylcholinesterase. Acetylcholine stimulates nicotinic and muscarinic receptors. When stimulated, these receptors have a range of effects.

toxicity

With drugs of this type, muscarine-like symptoms (nausea, vomiting, diarrhea, sweating, increased bronchial and salivary secretions and bradycardia) often appear with overdosage (cholinergic crisis).

absorption

Rapidly absorbed.

half life

Distribution half-life is 7 to 12 minutes. Elimination half-life is 33 to 110 minutes.

route of elimination

Edrophonium is primarily renally excreted with 67% of the dose appearing in the urine. Hepatic metabolism and biliary excretion have also been demonstrated in animals

drug interactions

Betamethasone: The corticosteroid, betamethasone, may decrease the effect of the anticholinesterase, edrophonium.

Dexamethasone: The corticosteroid, dexamethasone, may decrease the effect of the anticholinesterase, edrophonium.

Fludrocortisone: The corticosteroid, fludrocortisone, may decrease the effect of the anticholinesterase, edrophonium.

Hydrocortisone: The corticosteroid, hydrocortisone, may decrease the effect of the anticholinesterase, edrophonium.

Prednisolone: The corticosteroid, prednisolone, may decrease the effect of the anticholinesterase, edrophonium.

Prednisone: The corticosteroid, prednisone, may decrease the effect of the anticholinesterase, edrophonium.

Tacrine: The acetylcholinesterase inhibitor, Tacrine, may increase the adverse/toxic effects of Edrophonium, a cholinergic agonist. Monitor for increased cholinergic effects and toxicity.

Triamcinolone: The corticosteroid, triamcinolone, may decrease the effect of the anticholinesterase, edrophonium.