Use: to Dx Myasthenia Gravis
Receptors: Cholinesterase inhibitors
Mnemonics: eDrophonium to Diagnose Myasthenia Gravis
.Ed is the pro who can just use Phone (phonium) to diagnose myasthenia gravis over the phone by flirting with Esther so that she neglects holding on to the fish

Ed Phon: Edrophonium = phone instead of walking to the place <=> muscle weakness

Why it works?

The effects of edrophonium last only about five minutes. It is given by injection into a vein to confirm a diagnosis of myasthenia gravis. A single test dose usually causes a substantial improvement in muscle power in patients with the disease, but not in people whose muscle weakness has another cause. If edrophonium helps, a longer-acting anticholinesterase taken by mouth will usually be prescribed to treat the condition in the long-term, for example pyridostigmine. (1)

Other:

The Tensilon (edrophonium) challenge test is useful in diagnosing myasthenia gravis and in distinguishing myasthenic crisis from cholinergic crisis, due to its rapid onset and short duration of action (2)

(1): http://www.netdoctor.co.uk/medicines/aches-and-pains/a6635/edrophonium/
(2): http://emedicine.medscape.com/article/793136-overview#a5