Introduction:
Anaphylaxis to protamine is a rare and potentially fatal complication. Risk factors for protamine reaction may include history of prior cardiac surgery (with intraoperative protamine exposure), true fish allergy (as protamine is commonly derived from salmon sperm), history of vasectomy (due to formation of anti-sperm antibodies), insulindependent diabetes (due to exposure to neutral protamine Hagedorn (NPH) and other protamine containing forms of insulin), as well as excessively rapid administration of protamine.

Aim:
To report a case of anaphylaxis to protamine, increase awareness of protamine anaphylaxis and its treatments.

Case study:
Our patient had several risk factors not identified preoperatively and experienced a type 1 allergic reaction with anaphylaxis upon protamine administration. The patient was appropriately treated and made a full recovery from this potentially catastrophic event.

Results and discussion:
We present this case of a known drug reaction to remind our colleagues of the importance of screening for risk factors for protamine reaction, which include: shellfish allergy, insulin-dependent diabetes, prior protamine exposure, and vasectomy. The patient presented in this case had risk factors for allergic reaction to protamine including prior protamine exposure and vasectomy. The risks and benefits of protamine administration in a patient with multiple risk factors for protamine reaction are discussed, as is the controversy surrounding the clinical utility (or lack thereof) for protamine administration in elective peripheral vascular procedures.

Conclusions:
Identification of patient risk factors prior to protamine administration could result in (1) avoidance of protamine administration or (2) improved preparation for potential anaphylaxis.