Genetic polymorphisms in drug metabolizing enzymes can result in different phenotypes, such as poor, intermediate, extensive, or ultra-rapid metabolizers. For instance, variations in CYP2D6 can significantly affect the metabolism of drugs like codeine, where poor metabolizers may not experience the drug's analgesic effects, while ultra-rapid metabolizers may be at risk of toxicity. Understanding these genetic differences is crucial for personalized medicine and preventing adverse drug reactions.
