Iprindole molecule ball.png
Clinical data
Trade namesProndol, Galatur, Tertran
Other namesPramindole; WY-3263
Routes of
ATC code
Legal status
Legal status
  • In general: ℞ (Prescription only)
Pharmacokinetic data
Elimination half-life52.5 hours[1]
ExcretionUrine, Feces[2]
  • 3-(6,7,8,9,10,11-hexahydro-5H-cycloocta[b]indol-5-yl)-N,N-dimethylpropan-1-amine
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.024.485 Edit this at Wikidata
Chemical and physical data
Molar mass284.447 g·mol−1
3D model (JSmol)
  • c13c(n(c2ccccc12)CCCN(C)C)CCCCCC3
  • InChI=1S/C19H28N2/c1-20(2)14-9-15-21-18-12-6-4-3-5-10-16(18)17-11-7-8-13-19(17)21/h7-8,11,13H,3-6,9-10,12,14-15H2,1-2H3 checkY

Iprindole, sold under the brand names Prondol, Galatur, and Tertran, is an atypical tricyclic antidepressant (TCA) that has been used in the United Kingdom and Ireland for the treatment of depression but appears to no longer be marketed.[4][5][6][7] It was developed by Wyeth and was marketed in 1967.[8] The drug has been described by some as the first "second-generation" antidepressant to be introduced.[9] However, it was very little-used compared to other TCAs, with the number of prescriptions dispensed only in the thousands.[10]

Medical uses

Iprindole was used in the treatment of major depressive disorder in dosages similar to those of other TCAs.[5][11]


Iprindole has been associated with jaundice and hepatotoxicity and should not be taken by alcoholics or people with pre-existing liver disease.[8][12][13][14] If such symptoms are encountered iprindole should be discontinued immediately.

Side effects

Anticholinergic side effects such as dry mouth and constipation are either greatly reduced in comparison to imipramine and most other TCAs or fully lacking with iprindole.[15] However, it still has significant antihistamine effects and therefore can produce sedation, though this is diminished relative to other TCAs similarly.[16] Iprindole also lacks significant alpha-blocking properties, and hence does not pose a risk of orthostatic hypotension.[16]


Main article: Tricyclic antidepressant overdose

In overdose, iprindole is much less toxic than most other TCAs and is considered relatively benign.[17] For instance, between 1974 and 1985, only two deaths associated with iprindole were recorded in the United Kingdom, whereas 278 were reported for imipramine, although imipramine is used far more often than iprindole.[10][17]


Iprindole has been shown to be a potent inhibitor of the aromatic hydroxylation and/or N-dealkylation-mediated metabolism of many substances including, but not limited to octopamine, amphetamine, methamphetamine, fenfluramine, phenelzine, tranylcypromine, trimipramine, and fluoxetine, likely via inactivating cytochrome P450 enzymes.[3][18][19][20][21][22] It also inhibits its own metabolism.[21]

On account of these interactions, caution should be used when combining iprindole with other drugs.[3] As an example, when administered with amphetamine or methamphetamine, iprindole increases their brain concentrations and prolongs their terminal half-lives by 2- to 3-fold, strongly augmenting both their physiological effects and neurotoxicity in the process.[23][24][25]



See also: Pharmacology of antidepressants and Tricyclic antidepressant § Binding profiles

Site Ki (nM) Species Ref
SERT 1,620–3,300 Human [27][28]
NET 1,262 Human [27]
DAT 6,530 Human [27]
5-HT1A 2,800 Human [28]
5-HT2A 217–280 Human/rat [28][29]
5-HT2C 206 Rat [29]
α1 2,300 Human [30]
α2 8,600 Human [30]
β >10,000 Mammal [31][32]
D2 6,300 Rat [32]
H1 100–130 Human/rat [30][33]
H2 200–8,300 Guinea pig [32][34][35]
mACh 2,100 Human [30][36]
σ1 >10,000 Rat [37]
Values are Ki (nM). The smaller the value, the more strongly the drug binds to the site.

Iprindole is unique compared to most other TCAs in that it is a very weak and negligible inhibitor of the reuptake of serotonin and norepinephrine and appears to act instead as a selective albeit weak antagonist of 5-HT2 receptors; hence its classification by some as "second-generation".[38][39][40] Additionally, iprindole has very weak/negligible antiadrenergic and anticholinergic activity and weak although possibly significant antihistamine activity; as such, side effects of iprindole are much less prominent relative to other TCAs, and it is well tolerated.[15] However, iprindole may not be as effective as other TCAs, particularly in terms of anxiolysis.[38][16] Based on animal research, the antidepressant effects of iprindole may be mediated through downstream dopaminergic mechanisms.[41]

The binding affinities of iprindole for various biological targets are presented in the table to the right.[26] It is presumed to act as an inhibitor or antagonist/inverse agonist of all sites. Considering the range of its therapeutic concentrations (e.g., 63–271 nM at 90 mg/day),[1] only the actions of iprindole on the 5-HT2 and histamine receptors might be anticipated to be of possible clinical significance.[1] However, it is unknown whether these actions are in fact responsible for the antidepressant effects of iprindole. The plasma protein binding of iprindole and hence its free percentage and potentially bioactive concentrations do not seem to be known.


Only one study appears to have evaluated the pharmacokinetics of iprindole.[1][42] A single oral dose of 60 mg iprindole to healthy volunteers has been found to achieve mean peak plasma concentrations of 67.1 ng/mL (236 nmol/L) after 2 to 4 hours.[1] The mean terminal half-life of iprindole was 52.5 hours, which is notably much longer than that of other TCAs like amitriptyline and imipramine.[1] Following chronic treatment with 90 mg/day iprindole for 3 weeks, plasma concentrations of the drug ranged between 18 and 77 ng/mL (63–271 nmol/L).[1] Theoretical steady-state concentrations should be reached by 99% within 15 to 20 days of treatment.[1]


Iprindole is a tricyclic compound, specifically a cyclooctaindole (that is, an indole nucleus joined with a cyclooctyl ring), and possesses three rings fused together with a side chain attached in its chemical structure.[43] It is a tertiary amine TCA, although its ring system and pharmacological properties are very different from those of other TCAs.[15][44] Other tertiary amine TCAs that are similar to iprindole include butriptyline and trimipramine.[45][46] The chemical name of iprindole is 3-(6,7,8,9,10,11-hexahydro-5H-cycloocta[b]indol-5-yl)-N,N-dimethylpropan-1-amine and its free base form has a chemical formula of C19H28N2 with a molecular weight of 284.439 g/mol.[47] The drug has been used commercially as both the free base and the hydrochloride salt.[47] The CAS Registry Number of the free base is 5560-72-5 and of the hydrochloride is 20432-64-8.[47]


Iprindole was developed by Wyeth and was marketed in 1967.[8][48]

Society and culture

Generic names

Iprindole is the English and French generic name of the drug and its INN, USAN, BAN, and DCF, while iprindole hydrochloride is its BANM.[47][4][49] Its generic name in Spanish and German is iprindol while its generic name in Latin is iprindolum.[4] Iprindole was originally known unofficially as pramindole.[47][4]

Brand names

Iprindole has been marketed under the brand name Prondol by Wyeth in the United Kingdom and Ireland for the indication of major depressive disorder,[50] and has also been sold as Galatur and Tertran by Wyeth.[47]


Iprindole was previously available in the United Kingdom and Ireland[50] but seems to no longer be available for medical use in any country.[4][51]


  1. ^ a b c d e f g h Caillé G, de Montigny C, Besner JG (1982). "Quantitation of iprindole in plasma by GLC". Biopharmaceutics & Drug Disposition. 3 (1): 11–7. doi:10.1002/bdd.2510030103. PMID 7082775.
  2. ^ Sisenwine SF, Tio CO, Ruelius HW (April 1979). "The disposition of [14C]iprindole in man, dog, miniature swine, rhesus monkey and rat". Xenobiotica. 9 (4): 237–46. doi:10.3109/00498257909038726. PMID 113942.
  3. ^ a b c Rotzinger S, Bourin M, Akimoto Y, Coutts RT, Baker GB (August 1999). "Metabolism of some "second"- and "fourth"-generation antidepressants: iprindole, viloxazine, bupropion, mianserin, maprotiline, trazodone, nefazodone, and venlafaxine". Cellular and Molecular Neurobiology. 19 (4): 427–42. doi:10.1023/A:1006953923305. PMID 10379419. S2CID 19585113.
  4. ^ a b c d e Index Nominum 2000: International Drug Directory. Taylor & Francis. 2000. pp. 569–. ISBN 978-3-88763-075-1.
  5. ^ a b Ayd, Frank J. (2000). Lexicon of psychiatry, neurology, and the neurosciences. Philadelphia, Pa: Lippincott-Williams & Wilkins. ISBN 0-7817-2468-6.
  6. ^ Dictionary of organic compounds. London: Chapman & Hall. 1996. ISBN 0-412-54090-8.
  7. ^ Davison, Gerald C.; Hooley, Jill M.; Neale, John M. (1989). Readings in abnormal psychology. New York: Wiley. p. 186. ISBN 0-471-63107-8. iprindole.
  8. ^ a b c "Jaundice from iprindole (Prondol)". Drug and Therapeutics Bulletin. 9 (3): 10–1. January 1971. doi:10.1136/dtb.9.3.10. PMID 5548547. S2CID 31232918.
  9. ^ Horn AS, Trace RC (January 1983). "Second generation antidepressants: The pharmacological and clinical significance of selected examples". Drug Development Research. 3 (3): 203–211. doi:10.1002/ddr.430030302. S2CID 84018071.[dead link]
  10. ^ a b J. K. Aronson (2009). Meyler's Side Effects of Psychiatric Drugs. Elsevier. pp. 18–. ISBN 978-0-444-53266-4.
  11. ^ Wing, Lorna; Wing, J. K. (1982). Psychoses of uncertain aetiology. Cambridge, UK: Cambridge University Press. ISBN 0-521-28438-4.
  12. ^ Aronson, Jeffrey Kenneth (2008). Meyler's Side Effects of Psychiatric Drugs (Meylers Side Effects). Amsterdam: Elsevier Science. ISBN 978-0-444-53266-4.
  13. ^ Ajdukiewicz AB, Grainger J, Scheuer PJ, Sherlock S (September 1971). "Jaundice due to iprindole". Gut. 12 (9): 705–8. doi:10.1136/gut.12.9.705. PMC 1411804. PMID 4106521.
  14. ^ Clift AD (June 1971). "Allergy to iprindole (Prondole) with hepatotoxicity". British Medical Journal. 2 (5763): 712. doi:10.1136/bmj.2.5763.712. PMC 1796275. PMID 5556082.
  15. ^ a b c Gwynn Pennant Ellis; Geoffrey Buckle West (1970). Progress in Medicinal Chemistry: 7. Butterworth-Heinemann. pp. 25–. ISBN 978-0-408-70013-9.
  16. ^ a b c Rickels K, Chung HR, Csanalosi I, Sablosky L, Simon JH (September 1973). "Iprindole and imipramine in non-psychotic depressed out-patients". The British Journal of Psychiatry. 123 (574): 329–39. doi:10.1192/bjp.123.3.329. PMID 4583430. S2CID 23126539.
  17. ^ a b Cassidy S, Henry J (October 1987). "Fatal toxicity of antidepressant drugs in overdose". British Medical Journal (Clinical Research Ed.). 295 (6605): 1021–4. doi:10.1136/bmj.295.6605.1021. PMC 1248068. PMID 3690249.
  18. ^ Sedlock ML, Ravitch J, Edwards DJ (August 1985). "The effects of imipramine and iprindole on the metabolism of octopamine in the rat". Neuropharmacology. 24 (8): 705–8. doi:10.1016/0028-3908(85)90002-4. PMID 3939325. S2CID 39933551.
  19. ^ Hegadoren KM, Baker GB, Coutts RT, Dewhurst WG (March 1991). "Interactions of iprindole with fenfluramine metabolism in rat brain and liver". Journal of Psychiatry & Neuroscience. 16 (1): 5–11. PMC 1188281. PMID 2049371.
  20. ^ Yamamoto T, Takano R, Egashira T, Yamanaka Y (November 1984). "Metabolism of methamphetamine, amphetamine and p-hydroxymethamphetamine by rat-liver microsomal preparations in vitro". Xenobiotica. 14 (11): 867–75. doi:10.3109/00498258409151485. PMID 6506759.
  21. ^ a b Coutts RT, Hussain MS, Baker GB (December 1991). "Effect of iprindole on the metabolism of trimipramine in the rat". Journal of Psychiatry & Neuroscience. 16 (5): 272–5. PMC 1188365. PMID 1797102.
  22. ^ Aspeslet LJ, Baker GB, Coutts RT, Torok-Both GA (1994). "The effects of desipramine and iprindole on levels of enantiomers of fluoxetine in rat brain and urine". Chirality. 6 (2): 86–90. doi:10.1002/chir.530060208. PMID 8204417.
  23. ^ Fuller RW, Baker JC, Molloy BB (February 1977). "Biological disposition of rigid analogs of amphetamine". Journal of Pharmaceutical Sciences. 66 (2): 271–2. doi:10.1002/jps.2600660235. PMID 839428.
  24. ^ Fuller RW, Hemrick-Luecke S (July 1980). "Long-lasting depletion of striatal dopamine by a single injection of amphetamine in iprindole-treated rats". Science. 209 (4453): 305–7. Bibcode:1980Sci...209..305F. doi:10.1126/science.7384808. PMID 7384808.
  25. ^ Peat MA, Warren PF, Gibb JW (April 1983). "Effects of a single dose of methamphetamine and iprindole on the serotonergic and dopaminergic system of the rat brain". The Journal of Pharmacology and Experimental Therapeutics. 225 (1): 126–31. PMID 6187915.
  26. ^ a b Roth BL, Driscol J. "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 7 May 2022.
  27. ^ a b c Tatsumi M, Groshan K, Blakely RD, Richelson E (1997). "Pharmacological profile of antidepressants and related compounds at human monoamine transporters". Eur. J. Pharmacol. 340 (2–3): 249–58. doi:10.1016/s0014-2999(97)01393-9. PMID 9537821.
  28. ^ a b c Wander TJ, Nelson A, Okazaki H, Richelson E (1986). "Antagonism by antidepressants of serotonin S1 and S2 receptors of normal human brain in vitro". Eur. J. Pharmacol. 132 (2–3): 115–21. doi:10.1016/0014-2999(86)90596-0. PMID 3816971.
  29. ^ a b Pälvimäki EP, Roth BL, Majasuo H, Laakso A, Kuoppamäki M, Syvälahti E, Hietala J (1996). "Interactions of selective serotonin reuptake inhibitors with the serotonin 5-HT2c receptor". Psychopharmacology. 126 (3): 234–40. doi:10.1007/bf02246453. PMID 8876023. S2CID 24889381.
  30. ^ a b c d Richelson E, Nelson A (1984). "Antagonism by antidepressants of neurotransmitter receptors of normal human brain in vitro". J. Pharmacol. Exp. Ther. 230 (1): 94–102. PMID 6086881.
  31. ^ Bylund DB, Snyder SH (1976). "Beta adrenergic receptor binding in membrane preparations from mammalian brain". Mol. Pharmacol. 12 (4): 568–80. PMID 8699.
  32. ^ a b c Baker, Glen B.; Greenshaw, Andrew J. (1988). "In Vitro and Ex Vivo Neurochemical Screening Procedures for Antidepressants, Neuroleptics, and Benzodiazepines". Analysis of Psychiatric Drugs. Vol. 10. pp. 327–378. doi:10.1385/0-89603-121-7:327. ISBN 0-89603-121-7.
  33. ^ Tran VT, Chang RS, Snyder SH (1978). "Histamine H1 receptors identified in mammalian brain membranes with [3H]mepyramine". Proc. Natl. Acad. Sci. U.S.A. 75 (12): 6290–4. Bibcode:1978PNAS...75.6290T. doi:10.1073/pnas.75.12.6290. PMC 393167. PMID 282646.
  34. ^ Tsai BS, Yellin TO (1984). "Differences in the interaction of histamine H2 receptor antagonists and tricyclic antidepressants with adenylate cyclase from guinea pig gastric mucosa". Biochem. Pharmacol. 33 (22): 3621–5. doi:10.1016/0006-2952(84)90147-3. PMID 6150708.
  35. ^ Kanba S, Richelson E (1983). "Antidepressants are weak competitive antagonists of histamine H2 receptors in dissociated brain tissue". Eur. J. Pharmacol. 94 (3–4): 313–8. doi:10.1016/0014-2999(83)90420-x. PMID 6140176.
  36. ^ El-Fakahany E, Richelson E (January 1983). "Antagonism by antidepressants of muscarinic acetylcholine receptors of human brain". British Journal of Pharmacology. 78 (1): 97–102. doi:10.1111/j.1476-5381.1983.tb17361.x. PMC 2044798. PMID 6297650.
  37. ^ Largent BL, Gundlach AL, Snyder SH (1984). "Psychotomimetic opiate receptors labeled and visualized with (+)-[3H]3-(3-hydroxyphenyl)-N-(1-propyl)piperidine". Proc. Natl. Acad. Sci. U.S.A. 81 (15): 4983–7. Bibcode:1984PNAS...81.4983L. doi:10.1073/pnas.81.15.4983. PMC 391617. PMID 6087359.
  38. ^ a b Zis AP, Goodwin FK (September 1979). "Novel antidepressants and the biogenic amine hypothesis of depression. The case for iprindole and mianserin". Archives of General Psychiatry. 36 (10): 1097–1107. doi:10.1001/archpsyc.1979.01780100067006. PMID 475543.[permanent dead link]
  39. ^ Jaramillo J, Greenberg R (February 1975). "Comparative pharmacological studies on butriptyline and some related standard tricyclic antidepressants". Canadian Journal of Physiology and Pharmacology. 53 (1): 104–12. doi:10.1139/y75-014. PMID 166748.
  40. ^ Horn AS, Trace RC (July 1974). "Structure-activity relations for the inhibition of 5-hydroxytryptamine uptake by tricyclic antidepressants into synaptosomes from serotoninergic neurones in rat brain homogenates". British Journal of Pharmacology. 51 (3): 399–403. doi:10.1111/j.1476-5381.1974.tb10675.x. PMC 1776771. PMID 4451753.
  41. ^ Berettera C, Invernizzi R, Pulvirenti L, Samanin R (1986). "Chronic treatment with iprindole reduces immobility of rats in the behavioural 'despair' test by activating dopaminergic mechanisms in the brain". J. Pharm. Pharmacol. 38 (4): 313–5. doi:10.1111/j.2042-7158.1986.tb04576.x. PMID 2872301. S2CID 27863022.
  42. ^ Goodnick PJ (1994). "Pharmacokinetic optimisation of therapy with newer antidepressants". Clin Pharmacokinet. 27 (4): 307–30. doi:10.2165/00003088-199427040-00005. PMID 7834966. S2CID 46783536.
  43. ^ Yong Zhou (22 October 2013). Drugs in Psychiatric Practice. Elsevier. pp. 195–. ISBN 978-1-4831-9193-5.
  44. ^ Baxter BL, Gluckman MI (August 1969). "Iprindole: an antidepressant which does not block REM sleep". Nature. 223 (5207): 750–2. Bibcode:1969Natur.223..750B. doi:10.1038/223750a0. PMID 4308422. S2CID 4181062.
  45. ^ Patricia K. Anthony (2002). Pharmacology Secrets. Elsevier Health Sciences. pp. 39–. ISBN 1-56053-470-2.
  46. ^ Philip Cowen; Paul Harrison; Tom Burns (9 August 2012). Shorter Oxford Textbook of Psychiatry. OUP Oxford. pp. 532–. ISBN 978-0-19-162675-3.
  47. ^ a b c d e f J. Elks (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 702–. ISBN 978-1-4757-2085-3.
  48. ^ Richard C. Dart (2004). Medical Toxicology. Lippincott Williams & Wilkins. pp. 836–. ISBN 978-0-7817-2845-4.
  49. ^ I.K. Morton; Judith M. Hall (6 December 2012). Concise Dictionary of Pharmacological Agents: Properties and Synonyms. Springer Science & Business Media. pp. 156–. ISBN 978-94-011-4439-1.
  50. ^ a b Sean C. Sweetman (2009). Martindale: The Complete Drug Reference, 36th Edition. London: Pharmaceutical Press. ISBN 978-0-85369-840-1.
  51. ^ https://www.drugs.com/international/iprindole.html

Further reading