Intravenous bolus administration achieves steady state most rapidly because the entire drug dose is delivered directly into the bloodstream instantaneously, resulting in an immediate peak plasma concentration. This bypasses absorption and first-pass metabolism phases that delay the onset of action in other routes like oral, transdermal, or intramuscular. Oral tablets require gastrointestinal absorption, transdermal patches rely on skin permeation, and intramuscular injections involve gradual release from muscle tissue, all prolonging the time to reach steady state. Therefore, IV bolus provides the fastest systemic availability and steady-state attainment.

Reference: Goodman & Gilman's The Pharmacological Basis of Therapeutics, Brunton et al., 13th Edition.