Edrophonium chloride is primarily used in the medical field as a diagnostic tool to assess muscle weakness and fatigue, particularly in conditions like myasthenia gravis. It works by temporarily improving muscle strength by inhibiting the breakdown of acetylcholine, a neurotransmitter essential for muscle contraction. This allows healthcare providers to observe if symptoms improve, aiding in the diagnosis of neuromuscular disorders. Additionally, it is sometimes used to differentiate between myasthenic and cholinergic crises, as it can briefly alleviate symptoms in myasthenic patients but worsen conditions in cholinergic crises. Its fast-acting and short-duration effects make it suitable for diagnostic purposes rather than long-term treatment.