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A pharmacometric framework for norepinephrine transporter occupancy and dose equivalence across psychotropic medications

delete2026-08-04
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PRE
AI
M
Mohammed Aboukaoud
B
Bosmat Hoch
R
Revital Amiaz
DOI:10.1177/02698811261470450delete
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Abstract

Abstract

En 中文
<jats:sec> <jats:title>Background:</jats:title> <jats:p>Norepinephrine transporter (NET) inhibition is a relevant mechanism across psychotropic medications, although prescribing classifications are largely based on drug class rather than quantitative target engagement.</jats:p> </jats:sec> <jats:sec> <jats:title>Aims:</jats:title> <jats:p>To facilitate cross-drug comparisons of noradrenergic activity, we developed a pharmacometric model to estimate NET occupancy for 26 psychotropic agents and their active metabolites.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods:</jats:title> <jats:p>NET occupancy was estimated using National Institute of Mental Health Psychoactive Drug Screening Program Ki data, protein-binding-corrected plasma concentrations, a standard receptor occupancy model, and logit-derived ED50 values, and was compared with published positron emission tomography (PET) estimates.</jats:p> </jats:sec> <jats:sec> <jats:title>Results:</jats:title> <jats:p> After protein-binding correction, desipramine, milnacipran, and maprotiline showed very high NET occupancy (⩾90%), nortriptyline, doxepin, and norquetiapine showed high occupancy (70%–90%), and hydroxybupropion and duloxetine showed moderate occupancy (50%–70%). Clomipramine, atomoxetine, and reboxetine demonstrated moderate-low occupancy (30%–50%), whereas venlafaxine showed low occupancy (~28%). Hydroxybupropion exhibited substantially greater NET engagement (~68%) than bupropion (~2%), and most Selective serotonin reuptake inhibitors showed minimal occupancy (&lt;10%). Estimated ED50 values ranged from 6.6 mg (desipramine) to ⩾63 mg (duloxetine), and predicted occupancies correlated moderately with PET data ( <jats:italic toggle="yes">r</jats:italic>  = 0.76, <jats:italic toggle="yes">p</jats:italic>  = 0.028, R² = 0.58). </jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions:</jats:title> <jats:p>These findings suggest that variability in NET engagement across psychotropic medications may not be fully captured by conventional class-based classifications. The proposed framework offers a mechanism-informed approach to comparative pharmacological analysis and introduces a conceptual noradrenergic activity index. This approach may be useful for hypothesis generation in future studies integrating pharmacokinetic-pharmacodynamic modeling with in vivo imaging and clinical outcomes.</jats:p> </jats:sec>

Journal

Journal of Psychopharmacology cover
Journal of Psychopharmacology
IF:
5.5
Papers:
391
Citations:
9.1K

Organization

S
sheba medical center
Scholars:
340
Papers: 119
Citations: 0
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