Hypothalamic thermoregulatory centre

Antipyretic action Salicylates lower the elevated body temperature. Hypothalamic thermoregulatory centre acts as a thermostat of the body which maintains the balance between heat production and heat loss. Salicylates reset the hypothalamic thermostat which is disturbed during fever. They do not affect the heat production but they increase the heat loss by causing vasodilatation and sweating. The antipyretic action of salicylates is probably due to the inhibition of PG synthesis. 

Fever is common a mechanism is the release of interleukin-1 by leucocytes into the circulation which acts on receptors in the hypothalamic thermoregulatory centre, releasing prostaglandin Ej. 

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