Answer: C. The rate of metabolism
Explanation: Metabolism is a process of chemical reactions that change the drugs into water-soluble compounds for excretion. Without metabolism, the drug would continue to build up in a person’s system, eventually causing toxic effects. The liver is the primary site for drug metabolism.
The rate of metabolism is an important issue when a physician is deciding drug dosages. The drug half-life is the time the body takes to metabolize half of the available drug. Patients who are elderly or have liver or renal impairment may not have adequate metabolism of the drug, and the physician may need to prescribe a lower dosage.
Excretion or Elimination
The rate at which a drug is excreted or eliminated depends on the chemical composition of the drug, the rate of metabolism, and the route of administration.
When people age, their metabolic and excretory functions naturally slow down. Because the elderly can’t process and eliminate drugs at an ideal rate, they’re at increased risk for overdose. Drugs tend to accumulate in the elderly; the cumulative effect is more likely to occur in debilitated patients or those with chronic medical conditions... PF
