Which medication is a combination plasminogen activator derived from natural and synthetic sources?

• A. Anistreplase
• B. Thyroid hormone
• C. Sodium bicarbonate
• D. Fentanyl

Answer: (A)

The main idea here is a plasminogen activator that is formed as a complex combining a natural activator with plasminogen, modified to act as a prodrug. Anistreplase is exactly that: a covalent complex of streptokinase (a natural bacterial product) and plasminogen (human), chemically anisoylated to create a slow-acting, prolonged-form activator. When given IV, the complex gradually releases active components, and streptokinase then activates plasminogen to plasmin, which dissolves fibrin clots. This makes it a combination plasminogen activator derived from natural and synthetic sources—the natural part being streptokinase and plasminogen, with the anisoylation providing the synthetic modification that controls onset and duration. The other options don’t act as plasminogen activators or as combination complexes, so they don’t fit.