SHEET /vs/amitriptyline-vs-nortriptyline · COMPARISON
Amitriptyline vs Nortriptyline: what is the difference?
How they differ
Nortriptyline is amitriptyline with one methyl group removed, and the body performs exactly that conversion, so taking amitriptyline produces nortriptyline as an active metabolite. Both are tricyclic antidepressants that block serotonin and norepinephrine reuptake, and the missing methyl shifts the balance: nortriptyline leans more toward norepinephrine and carries fewer antihistamine and anticholinergic effects. That is why nortriptyline is generally the less sedating of the two and causes less dry mouth and constipation. Both are used at low levels for nerve pain and migraine prevention as well as for depression. Weights differ by the methyl group alone, 277.4 against 263.4.
Side by side
| Amitriptyline | Nortriptyline | |
|---|---|---|
| Formula | C20H23N | C19H21N |
| Molecular weight | 277.4 g/mol | 263.4 g/mol |
| Family | Tricyclic antidepressants | Tricyclic antidepressants |
| Everyday group | Prescription medicine | Prescription medicine |
| Functional groups | Aromatics | Amines, Aromatics |
| GHS signal wordThe supplier-filed hazard label, not a statement about ordinary use. | Danger | Warning |
| Oral LD50A single acute animal measure. It ranks nothing about human safety. | 140 mg/kg (oral, mouse) | 387 mg/kg (oral, mouse) |
| CAS number | 50-48-6 | 72-69-5 |
| PubChem CID | 2160 | 4543 |
Structural similarity 0.61 of 1, computed as a Morgan fingerprint Tanimoto coefficient. It measures shape, not effect.
Common questions
- What is the difference between Amitriptyline and Nortriptyline?
- Nortriptyline is amitriptyline with one methyl group removed, and the body performs exactly that conversion, so taking amitriptyline produces nortriptyline as an active metabolite. Both are tricyclic antidepressants that block serotonin and norepinephrine reuptake, and the missing methyl shifts the balance: nortriptyline leans more toward norepinephrine and carries fewer antihistamine and anticholinergic effects. That is why nortriptyline is generally the less sedating of the two and causes less dry mouth and constipation.
- Is Amitriptyline bigger than Nortriptyline?
- Amitriptyline is the heavier molecule, 277.4 g/mol against 263.4 g/mol for Nortriptyline. Amitriptyline is C20H23N and Nortriptyline is C19H21N.
- Which has the lower reported LD50, Amitriptyline or Nortriptyline?
- Amitriptyline, at 140 mg/kg (oral, mouse), against 387 mg/kg (oral, mouse) for Nortriptyline. An LD50 is one acute animal measurement, and the two here were not necessarily measured in the same species, so it is a data point rather than a ranking of how dangerous either is to a person.
Read the full records: Amitriptyline and Nortriptyline.