A 30-year-old female patient was prescribed oral cetirizine 10 mg at night for the treatment of chronic idiopathic urticaria. Within 15 min of oral ingestion of cetirizine 10 mg, the patient experienced severe pruritis and urticarial eruption all over the body. She developed severe breathlessness and was unable to speak.The patient became restless, disoriented and lost consciousness. She was rushed to the emergency room. Her pulse and blood pressure were unrecordable and air entry was decreased in both lungs. A diagnosis of anaphylactic shock was made. Cardiopulmonary resuscitation was started and epinephrine 0.5 mg of