Anaphylactoid reaction to adenosine.

Adenosine (Adenocard) is an endogenous purine nucleoside that has been approved recently for intravenous treatment of paroxysmal supraventricular tachycardia. With a serum half-life of 10 seconds, reported side effects including facial flushing, dyspnea, and chest pressure are common, but very transient. An elderly woman who received adenosine for paroxysmal supraventricular tachycardia had a prolonged anaphylactoid reaction that required pharmacological treatment. This is the first reported case of a prolonged anaphylactoid reaction to adenosine.