Pupil fails to dilate by giving cocaine in –
In periphery cocaine blocks the uptake of Adrenaline and Noradrenaline in Adrenergic nerve ending resulting in higher concentration of sympathetic neurotransmitters (Sympathomimetic effect) :
The peripheral sympathomimetic action of cocaine produces following effect :


Mydriasis
Rise in B.P.
Local vasoconstriction
Tachycardia


Therefore if the peripheral sympathetic system is paralysed it will lead to reverse of the above mentioned actions.
Central sympathetic paralysis
Central parasympathetic paralysis
Peripheral parasympathetic paralysis
Peripheral sympathetic paralysis.