One well-known example is codeine, a prodrug of morphine. It is metabolized by the liver enzyme CYP2D6, and genetic polymorphisms in this enzyme can lead to variations in morphine levels, sometimes resulting in respiratory depression or insufficient pain relief. Another example is clopidogrel, an antiplatelet prodrug that requires activation by hepatic enzymes. Variability in enzyme activity can lead to either increased risk of bleeding or therapeutic failure.
