Dosing and scheduling
Frequency
Last updated
How often a dose is repeated, and how long the gap between repeats is. Frequency and dose together decide total exposure, so the same dose at two different frequencies produces two different programmes. It is normally written as doses per day or per week, or as the interval between them.
Why it matters here
How often a compound needs repeating is set mainly by how fast it clears, which is a property of the compound rather than a matter of preference or convenience. Changing frequency changes the peaks and troughs inside the body even when the weekly total stays identical, and for some compounds the peaks are the part that matters.
What it is not
Frequency is not timing. Frequency is how many times and how far apart; timing is where in the day, and around what else, those doses fall. Two programmes can share a frequency exactly and still differ completely in timing.
Also called
- frequency
- dosing frequency
- dose frequency
- freq
- how often
- interval
- dosing interval
- times per week
- times per day
- per week
- qd
- bid
- twice daily
- once daily
Prescription shorthand leaks into forum posts: QD for once daily, BID for twice daily, ED for every day, EOD for every other day, Q2D for every two days. These come from clinical charting and get used loosely.
Compounds carrying this term
None on file yet. This term is in the controlled vocabulary but no compound record currently uses it — which is a statement about our coverage, not about the term.