When attempting to lower a person's body temperature in response to hyperthermia?

Shuddering produces warmth and vasoconstriction lessen the capacity of blood to dump its warmth load to the skin's surface where cooling happens. 
Hyperthermia is raised body temperature due to fizzled thermoregulation that happens when a body creates or assimilates more warmth than it scatters. Extraordinary temperature height at that point turns into a therapeutic crisis requiring quick treatment to forestall handicap or demise.