A drug's plasma level is a tug-of-war: each dose adds drug, while the body clears it away continuously. Because elimination is first-order — a fixed fraction leaves per unit time — the level between doses decays exponentially, and repeated doses accumulate into a rising sawtooth.
The sawtooth stops climbing at steady state, where the drug going in each interval exactly equals the drug coming out. Its average height is C_ss = dose rate ÷ clearance. Double the dose rate and it doubles; halve the clearance — a failing kidney — and it also doubles. Getting there takes about four to five half-lives, and t½ = 0.693 · V_d ÷ CL.
Clearance and volume do two different jobs. Clearance sets how high the level settles; volume of distribution sets only the timing — change V_d and the half-life shifts, but the average level does not move.
Waiting four half-lives is slow, so a loading dose fills the volume of distribution in one shot: LD = C_target · V_d lands you in the window on the very first dose. Loading is set by V_d; the maintenance rate is set by clearance.
The art is the therapeutic window. Too tall and the crest crosses the toxic ceiling; too shallow and the trough falls below effect. Smaller, more frequent doses shrink the swing so the whole cycle stays therapeutic — and when dosing stops, five half-lives later under a tenth of the peak remains.
Something in the simulation stopped unexpectedly — the lesson continues without it. You can move on; nothing you did was wrong.