ExCPT Pharmacy Technician Practice Exam 2026 – Complete Prep Resource

The intradermal route of administration is least likely to give a systemic effect because it involves injecting a substance into the dermis layer of the skin, which is not designed for rapid systemic absorption. The primary function of intradermal injections is to create a localized effect, often for skin testing or vaccinations, where the drug remains mostly confined to the area of injection rather than entering the bloodstream in significant amounts.

In contrast, the oral route involves ingestion and absorption through the gastrointestinal tract, leading to systemic circulation. Sublingual administration allows substances to dissolve under the tongue and enter the bloodstream quickly. Rectal administration can also contribute to systemic effects as the rectal mucosa allows for drug absorption directly into the circulation.

Thus, among the given routes, the intradermal administration specifically targets local tissues and minimizes the potential for systemic effects, making it the least likely option to result in those effects.