Inhibition of mTORC1 by rapamycin results in feedback activation of Akt S473 and aggravates hallmarks of osteoarthritis in female mice and non-human primates

[Beth]

I guess this means I should test because we haven’t done that.

Can you, or anyone, tell me what day of the week to go get a rapa blood test at labcorp after i take my 6mg on sat?

Thx

[LaraPo]

In other words, it continues to be an enigma wrapped in a riddle

[DrFraser]

2 days and 2 hours post dosing - so Monday, 2 hrs later than you took it on Saturday answers this question. Most of my patients test, and I put instructions in the chart for that (self ordered), but probably a third end up not testing, which usually has the need to take more conservative dosing if no testing.

That’s just my approach.

[LaraPo]

I doubt anyone can tell you with certainty. All depends what and for what purpose you want to measure. Usually trough is measured 24 hours after the last dose.

[DrFraser]

The trough is actually measured immediately before the next dose as you will certainly not be at the trough on a drug that has a 30-65 hr half life at 24 hours post dosing.

For a drug dosed q24 hours, @LaraPo is absolutely correct - but on cyclic dosing (and actually all drug dosing, the trough is the lowest level, we means right before the next dose).

[RapamycinCurious]

@adssx

@gris

When blood levels are already available, there’s no need for inaccurate formulas to convert doses across species/protocols. 5.2ng/mL trough in marmosets vs. 5-15ng/mL target trough in transplant patients who take 2-5mg/day, so we are talking a HED of 2mg/day.

Is this correct? I don’t know anything about that, but per ChatGPT:

These are cogent caveats, but are countered by the fact that the same trough levels are also observed at the low end of doses required to yield non-negligible life extension in mice. Everybody please see the original post I keep linking.