An unusual and interesting case of sequential serious adverse event.

Abstract: Hydrocortisone and pheniramine are frequently administered drugs for the management of severe allergic or anaphylactic reactions. However, there is hardly any literature that shows the association between the use of these drugs for the management of anaphylactic reactions that can induce serious adverse effect. We present a peculiar case of loss of consciousness following concurrent administration of intravenous pheniramine (Avil) and hydrocortisone (primacort) for the management of another drug-induced adverse reaction characterized by urticaria and pruritis that erupted succeeding intake of a fluoroquinolone group of the drug (ofloxacin). Loss of consciousness associated with pheniramine is a serious adverse drug reaction and its association was found out to be "probable/likely" according to the WHO-UMC Causality Assessment Scale. Such reactions, although rare, can be serious requiring immediate hospitalization and warrant vigilance.