Which of the following is a side effect of unfractionated heparin?

Unfractionated heparin is an anticoagulant that can have several side effects, one of which is osteopenia. This occurs because long-term use of heparin can interfere with the balance of bone remodeling processes. Heparin can inhibit osteoblast function and promote osteoclast activity, leading to a decrease in bone mineral density. Consequently, patients receiving prolonged therapy with unfractionated heparin may be at increased risk for osteoporosis and fractures.

Although hyperkalemia can occur with heparin therapy primarily as a result of its effects on aldosterone secretion, the link between unfractionated heparin and osteopenia is well recognized and directly relevant, making osteopenia the more accurate answer regarding the specific side effects associated with this medication. Hypotension and bradycardia can also be concerns in some cases, usually under specific conditions or with other concurrent medications, but they are not directly tied to unfractionated heparin's primary side effect profile.