|Oral, IM, IV|
|ATC code||N06AA10 (WHO)|
|Biological half-life||23-24 hours|
|Chemical and physical data|
|Molar mass||294.434 g/mol|
|3D model (Jmol)||Interactive image|
Trimipramine's primary use in medicine is in the treatment of major depressive disorder, especially where sedation is required due to its prominent sedative effects. Trimipramine also has some weak antipsychotic effects which are less pronounced than with the phenothiazine antipsychotic perazine.
Trimipramine is the only effective drug against insomnia known so far that does not alter the normal sleep architecture (there is evidence in medical journals that refute this last statement). In particular, it does not suppress REM sleep, and dreams are said to brighten during treatment.
Note: Bolded adverse effects are serious ones.
- Sedation — especially common with trimipramine compared to the other TCAs
- Anticholinergic effects including:
- - dry mouth
- - blurred vision
- - mydriasis
- - decreased lacrimation
- - constipation
- - urinary hesitancy or retention
- - reduced GI motility
- - tachycardia (high heart rate)
- - anticholinergic delirium (particularly in the elderly and in Parkinson's disease)
- Weight gain
- Orthostatic hypotension
- Sexual dysfunction including impotence, loss of libido and other sexual adverse effects
- Extrapyramidal side effects (e.g. parkinsonism, dystonia, etc.)
- ECG changes
- Increased liver function tests
- Syndrome of inappropriate secretion of antidiuretic hormone (SIADH)
- Blood dyscrasias including:
- Myocardial infarction
- Heart block
- QTc interval prolongation
- Sudden cardiac death
- Depression worsening
- Suicidal ideation
- Recent myocardial infarction
- Any degree of heart block or other cardiac arrhythmias
- Severe liver disease
- During breast feeding
- Hypersensitivity to trimipramine maleate or to any of the excipients
Compared to other tricyclic antidepressants trimipramine is relatively safe in overdose, although it is more dangerous than the selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) but less dangerous than bupropion in cases of overdose.
Mechanism of action
Trimipramine's mechanism of action differs from other TCAs. It is a weak to moderate reuptake inhibitor of serotonin, and an extremely weak inhibitor of norepinephrine and dopamine reuptake. Its main effects are due to considerable receptor antagonism as follows:
Trimipramine is a racemic compound with two enantiomers. CYP2C19 is responsible for the demethylation of (D)- and (L)-trimipramine to (D)- (L)-desmethyltrimipramine, respectively, and CYP2D6 is responsible for the 2-hydroxylation of (D)- and (L)-desmethyltrimipramine to (D)- and (L)-2-hydroxydesmethyltrimipramine, respectively. CYP2D6 also metabolizes (L)-trimipramine into (L)-2-hydroxytrimipramine.
Trimipramine maleate (as Surmontil) oral capsules were first approved by the Food and Drug Administration prior to January 1, 1982 in 25 mg and 50 mg formulations, with the 100 mg formulation having been approved on September 15, 1982. A generic version of all three formulations was given FDA approval on August 2, 2006.
- "PRODUCT INFORMATION SURMONTIL® Tablets and Capsules" (PDF). TGA eBusiness Services. Aspen Pharmacare Australia Pty Ltd. 28 November 2012. Retrieved 30 November 2013.
- "SURMONTIL (trimipramine maleate) capsule [Duramed Pharmaceuticals Inc]". DailyMed. Duramed Pharmaceuticals Inc. December 2012. Retrieved 30 November 2013.
- "Surmontil, Trimip (trimipramine) dosing, indications, interactions, adverse effects, and more". Medscape Reference. WebMD. Retrieved 30 November 2013.
- "Trimipramine 50mg Capsules - Summary of Product Characteristics (SPC)". electronic Medicines Compendium. Zentiva. 19 November 2012. Retrieved 30 November 2013.
- Rossi, S, ed. (2013). Australian Medicines Handbook (2013 ed.). Adelaide: The Australian Medicines Handbook Unit Trust. ISBN 978-0-9805790-9-3.
- Joint Formulary Committee (2013). British National Formulary (BNF) (65 ed.). London, UK: Pharmaceutical Press. ISBN 978-0-85711-084-8.
- Bender, S; Olbrich, HM; Fischer, W; Hornstein, C; Schoene, W; Falkai, P; Haarmann, C; Berger, M; Gastpar, M (March–April 2003). "Antipsychotic efficacy of the antidepressant trimipramine: a randomized, double-blind comparison with the phenothiazine perazine". Pharmacopsychiatry. 36 (2): 61–69. doi:10.1055/s-2003-39043. PMID 12734763.
- Eikmeier, G; Berger, M; Lodemann, E; Muszynski, K; Kaumeier, S; Gastpar, M (Winter 1991). "Trimipramine: An atypical neuroleptic?". International Clinical Psychopharmacology. 6 (3): 147–153. doi:10.1097/00004850-199100630-00003. PMID 1806621.
- Gross, G; Xin, X; Gastpar, M (November 1991). "Trimipramine: Pharmacological reevaluation and comparison with clozapine". Neuropharmacology. 30 (11): 1159–1166. doi:10.1016/0028-3908(91)90160-D. PMID 1663593.
- Schredl, M; Berger, M; Riemann, D (May 2009). "The effect of trimipramine on dream recall and dream emotions in depressive outpatients". Psychiatry Research. 167 (3): 279–286. doi:10.1016/j.psychres.2008.03.002. PMID 19403177.
- White, N; Litovitz, T; Clancy, C (December 2008). "Suicidal antidepressant overdoses: a comparative analysis by antidepressant type" (PDF). Journal of Medical Toxicology. 4 (4): 238–250. doi:10.1007/BF03161207. PMC 3550116. PMID 19031375.
- Roth, BL; Driscol, J (12 January 2011). "PDSP Ki Database". Psychoactive Drug Screening Program (PDSP). University of North Carolina at Chapel Hill and the United States National Institute of Mental Health. Retrieved 30 November 2013.
- Brunton, L; Chabner, B; Knollman, B (2010). Goodman and Gilman's The Pharmacological Basis of Therapeutics (12th ed.). New York: McGraw-Hill Professional. ISBN 978-0-07-162442-8.
- Eap CB, Bender S, Gastpar M, et al. (2000). "Steady state plasma levels of the enantiomers of trimipramine and of its metabolites in CYP2D6-, CYP2C19- and CYP3A4/5-phenotyped patients". Ther Drug Monit. 22 (2): 209–14. doi:10.1097/00007691-200004000-00012. PMID 10774635.
- "Generic Surmontil Availability". Drugs.com. Retrieved 22 March 2013.