Table Adverse effects of all heparins include Bleeding Thrombocytopenia (including heparin-induced thrombocytopenia with the potential for thromboembolism) Urticaria Anaphylaxis (rare) Bleeding caused by over-heparinization with unfractionated heparin can be treated with a maximum of 50 mg of protamine per 5000 units unfractionated heparin infused over 15 to 30 minutes.