Escalating every six weeks instead of four: what I observed over eight months — one year on posts 31–60
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
Nothing to add on the substance. Thank you for taking the question at face value.
Adding the boring version of Escalating every six weeks instead, because the interesting version keeps getting posted and the boring one is usually right.
Check the ordinary explanations, in order, and stop when one of them accounts for what you are seeing. Most of the time the second one does.
The arithmetic in post #33 is right; the assumption feeding it is the part to check.
Before the thread moves on from Escalating every six weeks instead — what is the sample size behind the claim? I am not being difficult; I have seen the same figure quoted from an n of four and from an n of four hundred.
The confident answers on Escalating every six weeks instead and the well-sourced answers are not the same answers, which is the most useful thing I have learned reading this category.
Post #33 describes the usual case. This is about the unusual one.
Small correction to my own earlier position on Escalating every six weeks instead. I had the units the wrong way round, which changes the conclusion by an order of magnitude and therefore changes it entirely.
Speaking only to Escalating every six weeks instead as I have actually seen it, rather than as it is usually described: the effect is real, it is smaller than the thread suggests, and the variance between people is larger than the effect.
The useful distinction on Escalating every six weeks instead is between what was measured and what was inferred from it. Both end up in the same sentence and only one of them has error bars.
Picking up post #38: that is the part I would want checked first.
Concentration and dose get conflated constantly in this subcategory. Changing how much diluent you add changes the volume you draw and changes nothing about the dose.
The mechanism is plausible, which is not the same as established.
On post #40 — agreed on the reasoning, with one qualification.
Small methodological point on Escalating every six weeks instead: repeating a measurement is cheap and resolves most of what is being argued about here at no cost to anyone.
The maximum studied dose is a fact about the trial and not a ceiling on the molecule. It is also the last point at which anything is known, which is the reason to treat it as one.
The four-week escalation interval is a convention from the pivotal trials, not a pharmacological constant. The pharmacological argument is that with a week-long half-life, four weeks approaches steady state and you can assess the dose fairly. That is an argument for not going faster. It is not an argument against going slower.
I am not the right person to answer the follow-up to this.
Bookmarking this. I will come back when I have something worth adding.
Confirming post #45 from a second method, which matters more than confirming it from a second person.
Where I would push back on the Escalating every six weeks instead consensus is the confidence, not the direction. The direction looks right. The confidence is borrowed.
Dose equivalence between different incretin analogues is a weak concept. The molecules differ in structure, half-life, receptor selectivity, and in what has been studied clinically. One mg of semaglutide is not equivalent to one mg of something else in any meaningful sense.
Take the reasoning and check the arithmetic; I do not always get it right.
Reaching a dose and staying there for a year: the question of whether a stable dose remains effective over years is mostly answered by the withdrawal trials and by real-world reports. The dose does not seem to stop working, but the longest trials are not indefinitely long.
The honest answer is that it depends, and here is what it depends on.
On post #47 — agreed on the reasoning, with one qualification.
The bit of Escalating every six weeks instead that nobody enjoys is that the answer changes depending on what you are trying to decide with it. Say what the decision is and the thread will converge.
That is the distinction I keep failing to hold on to. Written down now.
Steady state means the plasma concentration is stable from dose to dose. That happens around 4 to 5 half-lives. Before that, the concentration is rising with each dose. Escalating before steady state means escalating on incomplete information about the dose you are on.
The claim is narrower than it sounds, and deliberately so.
If you are new and reading this thread for the answer to Escalating every six weeks instead: the answer is conditional, the conditions are in the third reply, and the rest of the thread is worth skipping.
Post #51 describes the usual case. This is about the unusual one.
Where the Escalating every six weeks instead discussion usually stalls is that nobody wants to say "I do not know" and everyone is willing to say "it varies". Those are the same sentence with different clothes on.
Collapsed as off-topic by two members at trust level 3 or above
The four-week step is a trial convention, not a pharmacological constant. It is roughly four half-lives for a week-long half-life, which is the interval at which you are assessing a stable concentration rather than a rising one.
Adding it because I spent an afternoon working it out and nobody should have to twice.
Escalating before steady state means you are judging a dose you have not yet fully experienced. That is the whole argument against compressing the schedule and it is a good one.
Happy to be corrected if someone holds better data than mine.
Concentration and dose get conflated constantly in this subcategory. Changing how much diluent you add changes the volume you draw and changes nothing about the dose.
This topic was referenced in
- What steady state means for the decision to escalatePractice › Dosing & titration · 35 replies
- The lowest dose that does anything: is that a real question?Practice › Dosing & titration · 111 replies
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