**Core Concept**
Heparin-induced thrombocytopenia (HIT) is a serious complication of heparin therapy characterized by the formation of antibodies against the heparin-PF4 complex, leading to platelet activation, aggregation, and thrombocytopenia. Effective management of HIT requires the immediate discontinuation of heparin and the initiation of an alternative anticoagulant therapy.

**Why the Correct Answer is Right**
Lepirudin, a recombinant form of hirudin, is a direct thrombin inhibitor that is effective in managing HIT. Lepirudin works by directly inhibiting thrombin, thus preventing the formation of thrombi and the activation of platelets. Its use is recommended in patients with HIT due to its ability to provide effective anticoagulation without cross-reacting with the heparin-PF4 antibodies. Lepirudin is administered intravenously and its dose is adjusted based on the activated partial thromboplastin time (aPTT).

**Why Each Wrong Option is Incorrect**
**Option A:** Abciximab is a glycoprotein IIb/IIIa inhibitor that is used to prevent platelet aggregation during percutaneous coronary interventions. It is not indicated for the treatment of HIT.
**Option C:** Warfarin is an oral anticoagulant that works by inhibiting the synthesis of vitamin K-dependent clotting factors. However, its use in HIT is contraindicated due to the risk of worsening thrombosis.
**Option D:** Alteplase is a tissue plasminogen activator that is used to treat acute ischemic stroke and pulmonary embolism. It is not indicated for the treatment of HIT.

**Clinical Pearl / High-Yield Fact**
In patients with HIT, it is essential to discontinue all forms of heparin, including low molecular weight heparins and unfractionated heparin, and initiate an alternative anticoagulant therapy, such as lepirudin or argatroban, as soon as possible to prevent further thrombotic complications.

✓ Correct Answer: B. Lepirudin