RESEARCH MONOGRAPH · KDC-MN-221
Protriptyline
Protriptyline (Vivactil) is a secondary-amine tricyclic antidepressant from 1967 with one defining quirk: it is activating rather than sedating, which is the opposite of nearly every other drug in the class. The activating profile comes from preferential norepinephrine pump blockade combined with relatively little antihistamine activity. That made it historically useful for depressed patients with hypersomnia who needed alertness rather than further sedation. It has a long half-life because the liver metabolizes it slowly. Rarely prescribed now, displaced by SNRIs like duloxetine that achieve similar activation with much better tolerability. Not stocked by Kodiac. This monograph is provided for research and educational reference.
Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.
Tricyclic antidepressant (secondary amine, activating)
A secondary amine TCA distinguished by activating rather than sedating subjective profile; useful in depression with hypersomnia.
Abstract
Protriptyline (N-methyl-3-(5H-dibenzo[a,d]cyclohepten-5-yl)propan-1-amine; CAS 438-60-8; molecular formula C19H21N; molecular weight 263.38) is a secondary amine TCA approved by the FDA in 1967 under the trade name Vivactil. Distinct among TCAs for an activating subjective profile that contrasts with the sedation typical of the class; the activating profile is attributed to relatively higher NET-to-SERT selectivity and reduced H1 antagonism. NET Ki approximately 1.4 nM, SERT Ki approximately 20 nM. Plasma half-life is exceptionally long (54 to 92 hours) owing to slow CYP2D6 metabolism. The activating profile makes protriptyline a niche choice for depression with prominent hypersomnia or fatigue, including narcolepsy-associated depression where the wakefulness-promoting effect is therapeutic. Off-target activity is otherwise typical of secondary amine TCAs: muscarinic, mild H1, alpha-1, and sodium channel block. Approved for major depressive disorder; rarely first-line today owing to TCA-class limitations. Used as a reference compound for activating TCA pharmacology and in narcolepsy-related comorbidity research.
Mechanism of action
NET-preferring secondary amine TCA with reduced H1 antagonism producing an activating rather than sedating profile. Long half-life owing to slow CYP2D6 metabolism.
Reported research dose ranges
Reported research dose ranges in the literature.
References
- Biggs JT, Ziegler VE. Protriptyline plasma levels and antidepressant response. Clin Pharmacol Ther 1977.
- Moore N. Tricyclic antidepressants in narcolepsy. CNS Drugs 1996.
- Snyder S, Yamamura HI. Antidepressants and the muscarinic acetylcholine receptor. Arch Gen Psychiatry 1977.
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The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.
FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.