In a case of intravenous heparin therapy, which medication should be readily available on the nursing unit?

In the context of intravenous heparin therapy, having protamine sulfate readily available is crucial because it is the specific antidote used to reverse the effects of heparin in cases of overdose or when rapid anti-coagulation reversal is necessary for surgical procedures or when a patient is bleeding. Heparin is an anticoagulant that works by inhibiting certain factors in the coagulation cascade, and while it is effective for preventing blood clots, its effects can lead to increased risk of bleeding. In such situations, protamine sulfate can be administered to neutralize heparin, effectively minimizing the risk of bleeding and managing the patient's safety.

The other medications listed do not serve a similar role or are not relevant to heparin therapy. Potassium chloride is used to treat hypokalemia, while phytonadione (vitamin K) is an antidote for anticoagulant medications such as warfarin, not heparin. Aminocaproic acid, a medication that helps manage bleeding by inhibiting fibrinolysis, is not a direct antidote to heparin and therefore is not needed in this specific context of heparin therapy.