A patient is prescribed Peginterferon alfa-2a. What route is appropriate for administration?

• A. Oral
• B. Intramuscular
• C. Subcutaneous
• D. Intravenous

Answer: (C)

Pegylated interferon alfa-2a is a protein-based drug that must be given by injection rather than by mouth. The pegylation design increases the drug’s size and slows its absorption, making subcutaneous administration ideal because it provides a gradual, consistent absorption over time and supports the once-weekly dosing schedule. Oral administration wouldn’t be effective due to degradation in the GI tract and poor bioavailability. Intravenous injection would cause rapid, high peak levels with more adverse effects, while intramuscular routes are not the standard for this formulation. Therefore, subcutaneous injection is the appropriate route.