Accepted answer
Two administrations of 0.13 mg instead of one of 0.25 mg — the same 0.25 mg a week either way. Total weekly exposure is unchanged; what changes is the peak-to-trough ratio, and for an agent with a half-life measured in days the trough barely moves because the dosing interval is already short relative to it. The arithmetic is the easy part: 0.25 ÷ 2 = 0.13. Whether it is worth doing is a pharmacokinetic question, and nothing here is medical advice.
The relevant arithmetic is the accumulation ratio, which tells you how flat the profile already is at the current interval.
Splitting that same weekly dose into two half-doses at 3.5-day intervals gives τ/t½ = 0.5 and a peak-to-trough ratio of about 1.41. The profile is flatter, and the difference between a 2-fold and a 1.4-fold swing is not obviously perceptible.
Accumulation to steady state takes four to five half-lives regardless of how the dose is divided. Splitting does not shorten it and does not change the average exposure.
Titration schedules in the trial programmes were designed to manage gastrointestinal tolerability and are the evidenced approach to that problem.
For a weekly half-life, weekly dosing is already flat. Splitting buys very little.
7Confirming: I did the wrong thing here once and got exactly the predicted result. – rosa_mendieta 4 months ago 8I have added the label-the-vial suggestion to my own notes. Obvious in hindsight. – bufferline42 5 months ago add a comment