Patient complaints of muscle weakness. It was rivers on administration of neostigmine because
(Ref: Katzung 11/e p105) Neostigmine acts by inhibiting the enzyme acetylcholinesterase. This enzyme is involved in degradation of ACh,consequently neostigmine inereases the synaptic level of ACh. Muscle weakness can be improved by stimulation of NM receptors at muscle end plate due to increased ACh.