In ACS, how is heparin administered?

• A. Weight-based IV bolus + continuous infusion
• B. Subcutaneous injection
• C. Oral tablet daily
• D. Intramuscular injection

Answer: (A)

In acute coronary syndrome, rapid and controllable anticoagulation is essential. The preferred way to give heparin is as a weight-based IV bolus to quickly reach therapeutic levels, followed by a continuous IV infusion to maintain them. This approach allows the dose to be titrated based on lab monitoring (such as aPTT or anti‑Xa levels) and provides a reliable way to stop or reverse anticoagulation if bleeding occurs with protamine.

A typical regimen uses a bolus around 60 units per kilogram (maximum about 4,000 units) followed by an infusion of about 12 units per kilogram per hour (maximum around 1,000 units/hour), adjusted to achieve the target therapeutic range. Subcutaneous administration is not used for the initial ACS regimen because it provides slower onset and less controllable anticoagulation. Oral tablets and intramuscular injections are not appropriate for this purpose due to poor absorption and bleeding risk.