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Practice · Dosing & titration

Follow-up: Where the four-week escalation interval comes from, and what it is not

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TN
t.ndiayeTL2 Moderator10 May 2024#1
Community wiki post. Any member at trust level 3 or above can edit this post; every edit is recorded. Last edited by crossref_check on 1 Jun 2024.
  • 9 Jun 2024 — dexa_twice_yearly: Added the limitations paragraph that review asked for.
  • 1 Jun 2024 — crossref_check: Restructured into sections so the outline is navigable.
Editors: dexa_twice_yearly, crossref_check

Where the four-week escalation interval comes from, and what it is not Writing it up because I had to work it out twice and would rather nobody else did.

I have read the maintained page on this and I still have a gap, so I am asking rather than guessing.

Context: retatrutide, 25 weeks in, currently at a dose I reached by the standard four-week steps. Everything below is my own record rather than anything a clinician told me.

The specific question is the one in the title. What I have already checked: the labelling summary on the relevant documentation page, the two most-linked topics in this subcategory, and my own notes from the last 7 weeks. What I could not find is whether the answer changes at higher doses or whether it is the same arithmetic throughout.

If the answer is "it depends", I would rather know what it depends on than be given a number.

0 likes 2.2y
OB
owen.bradyTL4 Moderator15 May 2024#2
Staff post. Actions described here are recorded in the public moderation log and may be challenged in Meta.

the opening post is right about the mechanism and I think understates the practical bit.

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

18 likes 2.2y
JE
j.erdoganTL2 Moderator19 May 2024#3
owen.brady, post #2: the opening post is right about the mechanism and I think understates the practical bit. For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use. Go to post

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.

4 likes in reply to #2 2.2y
PP
peak_purityTL3Analytical chemist22 May 2024#4
owen.brady, post #2: the opening post is right about the mechanism and I think understates the practical bit. For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use. Go to post

Micro-titration: the concept of increments smaller than the labelled steps. It has no evidence base from trials but is described by some people. The downside is that very small increments are hard to measure accurately with a syringe.

0 likes in reply to #2 2.2y
MV
m.vukovicTL2 Moderator25 May 2024#5

Two things before anyone answers the substance.

First, the context in the first post is clear and specific. Second, the question is framed so that an answer can actually address it. Both are the norm here and both matter more than they sound.

27 likes 2.2y
NG
np_gilmoreTL3Nurse practitioner28 May 2024#6

post #5 answers the question as asked. The question underneath it is different.

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.

13 likes 2.2y
FR
f.rasmussenTL2 Moderator31 May 2024#7
m.vukovic, post #5: Two things before anyone answers the substance. First, the context in the first post is clear and specific. Second, the question is framed so that an answer can actually address it. Both are the norm here and both matter more than they sound. Go to post

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.

2 likes in reply to #5 2.2y
MD
m.dalgaardTL3Regular2 Jun 2024#8

Titrating on tolerability rather than on the calendar: some people escalate when they tolerate a dose well, others escalate on the prescribed schedule regardless. The published trials used a calendar-based schedule. Tolerability-based escalation has no formal evidence base but is not uncommon in practice.

0 likes 2.2y
LP
l.piresTL2 Moderator5 Jun 2024#9

Splitting a weekly dose in two: the pharmacokinetic argument against is that you want the benefit of long half-life, which gives a slowly changing plasma level from a weekly dosing schedule. Splitting it flattens the curve further but loses the convenience of once-weekly dosing. The trade-off is convenience versus a slightly flatter concentration curve.

19 likes 2.1y
ME
m.ekstromTL2 Moderator7 Jun 2024#10

How the published trials escalated: they used specific step sizes and intervals. The STEP programme used a particular cadence; the SURPASS and SURMOUNT programmes used slightly different ones. Reading them side by side shows the variation is real but small.

8 likes 2.1y
P
PSkarbekTL3Regular10 Jun 2024#11

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.

16 likes 2.1y
TA
t.abubakarTL2 Moderator12 Jun 2024#12

On post #8 — agreed on the reasoning, with one qualification.

Holding a dose indefinitely: the trials did not study indefinite holding at a non-maximum dose. The trials escalated to a target and then held that. What happens if you stay at an intermediate dose for years is not formally studied and extrapolation is the best available reasoning.

32 likes 2.1y
VK
v.krastevTL2 Moderator14 Jun 2024#13
j.erdogan, post #3: 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. Go to post

Picking up post #10: that is the part I would want checked first.

Stepping down deliberately: the withdrawal trials show that stopping is followed by regain. The step-down literature is thinner. The conservative assumption is that stepping down is followed by some regain, with the magnitude unknown.

1 like in reply to #3 2.1y
MA
m.achebeTL2 Moderator17 Jun 2024 · edited#14
np_gilmore, post #6: post #5 answers the question as asked. The question underneath it is different. 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… Go to post

The arithmetic of an intermediate dose: if the label says 1.0 mg and 2.0 mg, a dose strictly between them is off-label by definition. Some people compute it anyway. The reasoning is pharmacological — e.g., "I will split the difference between steps" — but it is reasoning from theory, not from evidence.

6 likes in reply to #6 2.1y
CD
c.dahlbergTL2 Moderator19 Jun 2024#15

Stepping down deliberately: the withdrawal trials show that stopping is followed by regain. The step-down literature is thinner. The conservative assumption is that stepping down is followed by some regain, with the magnitude unknown.

11 likes 2.1y
JB
j.baptistaTL2 Moderator21 Jun 2024#16

Worth separating two things that post #12 runs together.

The arithmetic of an intermediate dose: if the label says 1.0 mg and 2.0 mg, a dose strictly between them is off-label by definition. Some people compute it anyway. The reasoning is pharmacological — e.g., "I will split the difference between steps" — but it is reasoning from theory, not from evidence.

24 likes 2.1y
MR
m.rasmussenTL2 Moderator23 Jun 2024#17

I disagree with the reply above, and I think the disagreement is substantive rather than terminological.

The distinction being drawn does not survive when you look at the published data for this specific question. I would be glad to be shown wrong on this, because the version I am arguing against is more convenient.

0 likes 2.1y
ZO
z.onwukaTL2 Moderator25 Jun 2024#18
l.pires, post #9: Splitting a weekly dose in two: the pharmacokinetic argument against is that you want the benefit of long half-life, which gives a slowly changing plasma level from a weekly dosing schedule. Splitting it flattens the curve further but loses the convenience of once-weekly dosing. The trade-off is convenience versus a slightly flatter… Go to post

Holding a dose indefinitely: the trials did not study indefinite holding at a non-maximum dose. The trials escalated to a target and then held that. What happens if you stay at an intermediate dose for years is not formally studied and extrapolation is the best available reasoning.

3 likes in reply to #9 2.1y
AR
ambient_reviewTL3Regular27 Jun 2024#19

post #18 answers the question as asked. The question underneath it is different.

Micro-titration: the concept of increments smaller than the labelled steps. It has no evidence base from trials but is described by some people. The downside is that very small increments are hard to measure accurately with a syringe.

7 likes 2.1y
PO
pe.onwukaTL2 Moderator29 Jun 2024#20

On post #16 — agreed on the reasoning, with one qualification.

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.

17 likes 2.1y
SS
steady_stateTL3Regular1 Jul 2024#21
m.vukovic, post #5: Two things before anyone answers the substance. First, the context in the first post is clear and specific. Second, the question is framed so that an answer can actually address it. Both are the norm here and both matter more than they sound. Go to post

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.

2 likes in reply to #5 2.1y
NC
n.cabreraTL2 Moderator3 Jul 2024#22
steady_state, post #21: 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. Go to post

Titrating on tolerability rather than on the calendar: some people escalate when they tolerate a dose well, others escalate on the prescribed schedule regardless. The published trials used a calendar-based schedule. Tolerability-based escalation has no formal evidence base but is not uncommon in practice.

0 likes in reply to #21 2.1y
SB
sharps_binTL26 Jul 2024#23
SV
s.vukovicTL2 Moderator7 Jul 2024#24

This follows post #21 rather than contradicting it.

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.

13 likes 2.1y
OF
outline_firstTL3Wiki editor9 Jul 2024#25
j.erdogan, post #3: 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. Go to post

How the published trials escalated: they used specific step sizes and intervals. The STEP programme used a particular cadence; the SURPASS and SURMOUNT programmes used slightly different ones. Reading them side by side shows the variation is real but small.

0 likes in reply to #3 2y
SO
se.okaforTL2 Moderator11 Jul 2024 · edited#26

When a dose reduction is the correct response to a side effect: if a side effect is dose-dependent (nausea, constipation, injection discomfort), reducing the dose is a reasonable response. If the side effect is not dose-dependent (e.g., hypoglycemia with insulin), dose reduction does not address the issue.

0 likes 2y
CT
cannula_traceTL3Regular13 Jul 2024#27

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.

20 likes 2y
GA
g.amankwahTL2 Moderator15 Jul 2024#28

Picking up post #25: that is the part I would want checked first.

I disagree with the reply above, and I think the disagreement is substantive rather than terminological.

The distinction being drawn does not survive when you look at the published data for this specific question. I would be glad to be shown wrong on this, because the version I am arguing against is more convenient.

9 likes 2y
B
BirkelandTL3Regular17 Jul 2024#29

Worth separating two things that post #25 runs together.

The arithmetic of an intermediate dose: if the label says 1.0 mg and 2.0 mg, a dose strictly between them is off-label by definition. Some people compute it anyway. The reasoning is pharmacological — e.g., "I will split the difference between steps" — but it is reasoning from theory, not from evidence.

8 likes 2y
VR
v.rautioTL2 Moderator19 Jul 2024#30
sharps_bin, post #23: I read post #21 twice before replying, because I had assumed the opposite. Splitting a weekly dose in two: the pharmacokinetic argument against is that you want the benefit of long half-life, which gives a slowly changing plasma level from a weekly dosing schedule. Splitting it flattens the curve further but loses the convenience of… Go to post

post #29 is right about the mechanism and I think understates the practical bit.

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

2 likes in reply to #23 2y