Which statement correctly defines onset of action and its relevance to nursing care?

• A. Onset is time to first therapeutic effect; used to predict when to monitor response.
• B. Onset is the time to peak effect; used to schedule dosage intervals.
• C. Onset is the total duration of effect; used to decide when to re-dose.
• D. Onset is the time to reach maximum plasma concentration; used to assess toxicity.

Answer: (A)