While PGx is often thought of as just an analysis of CYP450 enzymes, it's important to note that not all PGx changes observed with drug metabolism are due to CYP450 enzymes. There are other enzymes that, while not in the CYP450 class, can still have mutations or polymorphisms that lead to variable functions. Table 4 provides a list of enzymes for known mutations associated with clinical effects. Note that not all the enzymes on the list are CYP450 enzymes.
Table 4. Enzymes Associated with Drug Metabolism Changes. | Enzymes | Substrates (Drugs) |
| Acetaldehyde dehydrogenase | Alcohol |
| Acetylcholinesterase | Succinylcholine |
| Alcohol dehydrogenase | Alcohol |
| Dihydropyrimidine dehydrogenase | Fluorouracil |
| CYP2C9 | Warfarin, phenytoin, losartan |
| CYP2C19 | Diazepam, omeprazole (Prilosec) |
| CYP2D6 | Many antidepressants, opioids, antiarrhythmics |
| Glucose-6-phosphate dehydrogenase | Aspirin, quinidine |
| N-acetyltransferase | Procainamide, isoniazid |
| Thiopurine methyltransferase | 6-mercaptopurine |
| UDP-glucuronosyl transferase | Acetaminophen, tolbutamide, irinotecan |
