Final answer:
Diuretics can affect changes in the rate of excretion in pharmacokinetics step #4 (Excretion). Loop diuretics, for example, inhibit the reabsorption of sodium and chloride ions in the ascending limb of the loop of Henle in the nephron.
Step-by-step explanation:
The drug that can affect changes in the rate of excretion in step #4 of pharmacokinetics (Excretion) is a. Diuretics. Diuretics are medications that increase urine production and can impact the rate of excretion. One example of a diuretic is a loop diuretic, which works by inhibiting the reabsorption of sodium and chloride ions in the ascending limb of the loop of Henle in the nephron.