A nurse is preparing to administer heparin IV to a patient with a deep vein thrombosis. Before administration, which item is essential to have readily available at the bedside and why?

Calcium gluconate, because it prevents heparin-induced hypocalcemia.

Protamine sulfate, because it is the antidote used to reverse heparin in case of overdose or excessive bleeding.

Atropine, because it counteracts bradycardia that may occur with heparin use.

Vitamin K, because it reverses the effects of heparin if bleeding occurs.