PsychoTropicalResearch, serotonin and serotonin syndrome research.
Antidepressants - Receptor affinities
Antidepressants - Receptor affinities
Date Created: 05/04/1999 Last Modified: 25/10/2000 Last Checked: 17/04/2004
The evidence that useful predictions can be made about the properties and side effects of psychotropic drugs from receptor affinity data is now very strong. eg sedation and weight gain are proportional to H1 potency right across 'classes' from anti-histamines to anti-psychotics and anti-depressants. It is advisable for practitioners to be cognisant of these developments because they underpin the rational, scientific and safe use of all of these drugs.
Easy and quick access to this data will assist in coming to informed and rational choices for patients.
See other notes in the full version of 'Psychopharmacology Update Notes' for details of receptor affinities at other relevant receptors.
Anti-muscarinic side effects for antidepressant drugs.
Effects of muscarinic blockade:-- dry mouth, blurry vision, precipitation of glaucoma, constipation, urinary retention, resting tachycardia, impaired memory (and confusion / delirium in higher doses).
From least potent >> most potent.
ie amitriptyline is the most potent M1 blocker and causes more of these side effects.
- Reboxetine probably >35000
- Bupropion 35000
- Sertraline 1300
- Fluoxetine 1000
- Desipramine 210
- Paroxetine 80
- Imipramine 60
- Doxepin 52
- Trimipramine 50
- Nortriptyline 50
- Dothiepin 38
- Clomipramine 25
- Amitriptyline 13
Other than paroxetine the SSRIs probably have no significant action on muscarinic receptors; of the TCAs, desipramine is the least problematical but can still cause confusion in the elderly sometimes. New noradrenalin reuptake inhibitors (NRIs) like reboxetine have a clear advantage here.
All text ©Dr Ken Gillman MRC Psych - PsychoTropical Research®
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