What is prodrug?

Answer 1

A prodrug is a drug that is inactive when you take it (when it is administered), but then becomes active once your body starts to break it down (usually through metabolism). Stimulant simply refers to a class of drug. The opposite would be a non-stimulant. However, it is a different adjective describing the drug and is not part of "prodrug". That is, to be clear, the drug you're looking at is both a stimulant and a prodrug.

Answer 2

A prodrug is a pharmacological substance (drug) that is administered in an inactive (or significantly less active) form. Once administered, the prodrug is metabolised in vivo into an active metabolite. The rationale behind the use of a prodrug is generally for absorption, distribution, metabolism, and excretion (ADME) optimization. Prodrugs are usually designed to improve oral bioavailability, with poor absorption from the gastrointestinal tract usually being the limiting factor.