Protamine-Induced Hypotension and Pulmonary Arterial Hypertension

Protamine is a routinely used safe antidote for heparin reversal in cardiovascular surgeries. Protamine was first introduced to prolong the action of insulin preparations. As protamine interacts with platelets and fibrinogen and has an anticoagulant effect of its own, minimal amount is given to neutralize heparin present in plasma. Although infrequent, protamine is associated with serious adverse drug reactions (ADRs), especially in patients with previous history of protamine hypersensitivity. Here, we report a case of protamine-induced pulmonary arterial hypertension and peripheral vascular collapse in a 60-year-old diabetic male patient who had undergone on-pump coronary artery bypass grafting in a tertiary care center. This was a definite, nonpreventable, severe ADR as per causality, preventability, and severity assessment scale. This patient had no previous history of protamine hypersensitivity and was not on any insulin preparations. Despite precise timely treatment and other resuscitative measures, the patient expired subsequent to these ADRs. This case report throws light on the grave requirement in urgent evolvement of pharmacogenetic and pharmacokinetic tools to detect patients who are at risk of precipitating these ADRs and thus to take precautions to prevent them.