Reading about receptor desensitisation and trying to work out which of the effects adapt over time and which do not, because people clearly experience both.
What would genuinely help is knowing which effects tachyphylax and which persist, because the answer explains why tolerability improves while the appetite effect keeps working.
Practical detail welcome, however dull — the duller the better.
nick_newbie said:Reading about receptor desensitisation and trying to work out which of the effects adapt over time and which do not, because people clearly experience…
Pharmacist here. I want to add the drug interaction perspective on the pharmacology.
Key points from a pharmacokinetic standpoint:
- GLP-1 agonists delay gastric emptying, which can affect Tmax of co-administered oral medications
- Monitor patients on warfarin (INR), levothyroxine (TSH), and oral contraceptives during dose titration
- The albumin-binding mechanism of semaglutide (C-18 fatty acid linker) gives it the ~168-hour half-life that enables weekly dosing
- Steady state is reached at approximately 4-5 weeks after dose initiation or adjustment
Re: the pharmacology specifically — the pharmacology here is well-characterized and the clinical implications are straightforward.
PharmacoVig_BOS said:I want to add the drug interaction perspective on the pharmacology.
PharmacoVig_BOS has the substance of this right. The condition it depends on is worth stating. The pharmacokinetics explain nearly every practical question asked here. Albumin binding above 99% slows clearance enough to make weekly dosing possible; a terminal half-life near a week means four to five weeks to steady state and therefore a four-week titration interval; subcutaneous bioavailability around 89% means injection site barely matters. Those three facts answer most timing questions before they are asked.
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Shop Reference Standardsnick_newbie said:Reading about receptor desensitisation and trying to work out which of the effects adapt over time and which do not, because people clearly experience…
Mine went the same way, slower. Posting only so the count is not one.
Clinical perspective, offered as context rather than as advice.
Amycretin (AMY/GLP-1 dual agonist) emerging data relevant to the pharmacology: Phase 1 showed -13.1% body weight at only 12 weeks, the fastest trajectory ever seen for an anti-obesity agent[1].
Amylin receptor agonism enhances satiety signaling through the area postrema and reduces glucagon secretion. Combined with GLP-1R agonism, this dual mechanism may produce even greater efficacy than current agents.
Early-stage data — interpret with caution. But the trajectory is extraordinary.
[1] Novo Nordisk investor presentation, September 2023.