Antipyretics and delirious behavior during febrile illness.

Background: The purpose of the present paper was to study the use of antipyretics in children with delirium associated with fever in order to clarify their possible adverse effects. Methods: The use of antipyretics was investigated in 26 children with delirious behavior associated with fever. Temporal relation between delirious behavior and the use of antipyretics was recognized in six children. Results: In four children, delirious behavior was observed soon after administration of antipyretics. The antipyretics used were acetaminophen in two children, mephenamate in one, and diclofenac in one. In the other two children, delirious behavior was observed when body temperature began to fall 1-2 h after administration of antipyretics. The antipyretics used were acetaminophen in one child and mephenamate in one. Conclusion: A temporal relationship between antipyretics and delirious behavior was observed in some patients with febrile delirium. This suggests that antipyretics can be a trigger of delirium.