Drug used in unstable angina to prevent Myocardial infarction is
## **Core Concept**
Unstable angina is a condition characterized by chest pain or discomfort due to transient myocardial ischemia, often a precursor to myocardial infarction. Management involves anti-ischemic therapy, antiplatelet agents, and anticoagulants to prevent progression to myocardial infarction.
## **Why the Correct Answer is Right**
The correct answer, **C. Heparin**, is used in the management of unstable angina to prevent myocardial infarction. Heparin works by activating **antithrombin III**, which inhibits **thrombin** (Factor IIa) and other coagulation factors, thereby preventing the formation of blood clots that can occlude coronary arteries. This anticoagulant effect helps in reducing the risk of myocardial infarction in patients with unstable angina.
## **Why Each Wrong Option is Incorrect**
- **Option A:** While **Aspirin** (an antiplatelet agent) is indeed used in the management of unstable angina to prevent myocardial infarction by inhibiting platelet aggregation, the question seems to focus on a drug specifically used to prevent myocardial infarction through a different mechanism.
- **Option B:** **Metoprolol**, a beta-blocker, is used in unstable angina for its anti-ischemic effects by reducing heart rate and myocardial oxygen demand. However, it does not directly prevent clot formation or myocardial infarction like an anticoagulant would.
- **Option D:** **Nifedipine**, a calcium channel blocker, can also be used in angina for its vasodilatory effects, reducing myocardial oxygen demand. However, like beta-blockers, it does not directly prevent myocardial infarction through anticoagulation.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that in the setting of unstable angina, the immediate goals are to relieve ischemia, prevent myocardial infarction, and stabilize the patient. **Heparin** is specifically used for its anticoagulant properties to prevent the progression to myocardial infarction, often in conjunction with antiplatelet agents like **aspirin**.
## **Correct Answer:** C. Heparin.