What statement best differentiates dalteparin (Fragmin) from unfractionated heparin?

• A. Dalteparin is a low-molecular-weight heparin that is more predictable in its effect and has a lower risk of bleeding.
• B. There is no real difference; dalteparin is preferred because it is less expensive.
• C. Dalteparin dosing is based on body weight, whereas heparin is fixed-dose.
• D. Dalteparin is an oral anticoagulant while heparin is injectable.

Answer: (A)

Dalteparin is a low-molecular-weight heparin, and the key difference from unfractionated heparin is its pharmacokinetic and safety profile. LMWHs have smaller, more uniform molecules, which leads to a more predictable anticoagulant effect and a longer, steadier half-life. This makes dosing more reliable and often reduces the need for routine laboratory monitoring (such as aPTT) compared with unfractionated heparin. Clinically, this also translates to a lower risk of major bleeding and a lower risk of heparin-induced thrombocytopenia with dalteparin, though HIT can still occur.

The other statements don’t fit: dalteparin is not an oral anticoagulant—it is injected; there isn’t a blanket rule that dalteparin is cheaper or more expensive than unfractionated heparin in all settings, and dosing strategies aren’t simply fixed versus weight-based—UFH can be weight-based but often requires more monitoring and adjustment.