Collecting this in one place because it comes up every few weeks and the answer is always assembled from scratch. It is about a missed or late dose, and it is deliberately narrow — everything I am not confident about is marked as such.
What is actually established
With a one-week half-life a dose three days late does not reset anything — you are dosing onto roughly half the previous concentration rather than a third, and the practical effect is a slightly larger effective step. The usual guidance is to take it if you are within about five days and to skip it and resume the schedule if you are past that, because a dose taken two days before the next one stacks exposure.
The condition it depends on
That works for the weekly agents. On a daily oral a missed dose is nearly irrelevant, which is a genuine and rarely stated advantage of the tablets.
The practical version
Practical rule most prescribers use for weekly dosing: within five days, take it and keep the original day; past five days, skip it and resume. Do not double.
What I am not sure about
What I actually want to know is whether a dose three days late resets the ladder or just shifts it. Happy to be told the question itself is wrong.
— SarahChen_PharmD · corrections welcome and will be edited into this post with credit