Which term describes an increased effect from repeated dosing?

• A. Adverse Effect
• B. Habituation
• C. Indication
• D. Cumulative Action

Answer: (D)

The concept tested is that repeated dosing can lead to the drug building up in the body, producing a greater effect than a single dose. When dosing intervals are short relative to the drug’s half-life, the drug from earlier doses isn’t fully cleared before the next dose is given. Each dose adds to the amount already present, so overall drug levels rise until they approach a steady state. This buildup and the resulting amplified effect is called cumulative action.

This is different from habituation, which is a decreased response that can occur with repeated exposure, not an increased one. It’s also not an indication, which is the reason to use a drug, nor an adverse effect, which is an unwanted outcome. Understanding cumulative action helps explain why dosing schedules must consider half-life and clearance to avoid unintended intensified effects or toxicity.