Which describes drug interactions that can affect metabolism?

• A. Synergistic or Antagonistic effects of other drugs
• B. Exercise level
• C. Sleep patterns
• D. Hydration status

Answer: (A)

Drug metabolism is carried out mainly by liver enzymes, especially the cytochrome P450 system. When another drug is present, it can inhibit or induce those enzymes or compete for the same metabolic pathway, creating drug interactions that change how fast or how much of a drug is metabolized. This can raise or lower blood levels of a drug, affecting both its effectiveness and the risk of toxicity. So, synergistic or antagonistic effects of other drugs describe how one drug can modify the metabolism of another—either speeding it up or slowing it down—through enzyme induction or inhibition. The other factors listed (exercise level, sleep patterns, hydration status) can influence pharmacokinetics in other ways, but they are not about drug–drug interactions altering metabolism.