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Yohimbine structure.svg
Clinical data
Routes of
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability7-86% (mean 33%)
Elimination half-life0.25-2.5 hours[1]
ExcretionUrine (as metabolites)
CAS Number
PubChem CID
ECHA InfoCard100.005.157 Edit this at Wikidata
Chemical and physical data
Molar mass354.44 g/mol (base)
390.90 g/mol (hydrochloride)
3D model (JSmol)

Yohimbine (/jˈhɪmbn/)[2], synonym quebrachine, is a Indoloquinolizidine alkaloid derived from the bark of the Pausinystalia johimbe tree from Central Africa; also from the bark of the unrelated South American tree Aspidosperma quebracho-blanco. It is a veterinary drug used to reverse sedation in dogs and deer. Yohimbine has been studied as a potential treatment for erectile dysfunction, but there is insufficient evidence to rate its effectiveness.[3] Extracts from yohimbe have been marketed as dietary supplements for improving sexual function.[4][5]


Yohimbine is a drug used in veterinary medicine to reverse the effects of xylazine in dogs and deer.[6]

Yohimbe extracts, which contain yohimbine, have been used in traditional medicine and marketed as dietary supplements.[4]


Depending on dosage, yohimbine can either increase or decrease systemic blood pressure (through vasoconstriction or vasodilation, respectively), because yohimbine has highest affinity for the α2 receptor, small doses can increase blood pressure by causing a relatively selective α2 blockade. Yohimbine also, however, interacts with α1 receptors, albeit with lower affinity; therefore, at higher doses an α1 blockade can occur and overwhelm the effects of the α2 blockade, leading to a potentially dangerous drop in blood pressure.[7] Higher doses of oral yohimbine may create numerous side effects, such as rapid heart rate, overstimulation, anomalous blood pressure, cold sweating, and insomnia.

Extracts and chemistry[edit]

Yohimbe (Pausinystalia johimbe) is a tree that grows in western and central Africa;[8] yohimbine was named as originally extracted from the bark of yohimbe in 1896 by Adolph Spiegel.[9] (In fact, it had been isolated earlier from the bark of the South American tree A. quebracho-blanco and named as quebrachine, but this was overlooked). In 1943 the correct constitution of yohimbine was proposed by Witkop.[10] Fifteen years later, van Tamelen used a 23-step synthesis to become the first person to achieve the synthesis of yohimbine.[11][12][13]


Yohimbine has high affinity for the α2-adrenergic receptor, moderate affinity for the α1 receptor, 5-HT1A, 5-HT1B, 5-HT1D, 5-HT1F, 5-HT2B, and dopamine D2 receptors, and weak affinity for the 5-HT1E, 5-HT2A, 5-HT5A, 5-HT7, and dopamine D3 receptors.[14][15] It behaves as an antagonist at α1-adrenergic, α2-adrenergic, 5-HT1B, 5-HT1D, 5-HT2A, 5-HT2B, and dopamine D2, and as a partial agonist at 5-HT1A.[14][16][17][18] Yohimbine interacts with serotonin and dopamine receptors in high concentrations.[19]

Pharmacologic profile
Molecular target Binding affinity
(Ki in nanomolar)[20]
Pharmacologic action
Species Source
SERT 1,000 Inhibitor Human Frontal cortex
5-HT1A 346 Partial agonist Human Cloned
5-HT1B 19.9 Antagonist Human Cloned
5-HT1D 44.3 Antagonist Human Cloned
5-HT1E 1,264 Unknown Human Cloned
5-HT1F 91.6 Unknown Human Cloned
5-HT2A 1,822 Antagonist Human Cloned
5-HT2B 143.7 Antagonist Human Cloned
5-HT7 2,850 Unknown Human Cloned
α1A 1,680 Antagonist Human Cloned
α1B 1,280 Antagonist Human Cloned
α1C 770 Antagonist Human Cloned
α1D 557 Antagonist Human Cloned
α2A 1.05 Antagonist Human Cloned
α2B 1.19 Antagonist Human Cloned
α2C 1.19 Antagonist Human Cloned
D2 339 Antagonist Human Cloned
D3 3,235 Antagonist Human Cloned


Yohimbine has been studied as a way to improve the effects of exposure therapy in people with post traumatic stress disorder.[22][23]

It has also been studied as a potential treatment for erectile dysfunction but there is insufficient evidence to rate its effectiveness.[7][3] It is illegal in the United States to market an over the counter product containing yohimbine as a treatment for erectile dysfunction without getting FDA approval to do so.[24] Nevertheless, the quantity of yohimbine in dietary supplements, often advertised as promoting sexual function, has been found to overlap with prescription doses of yohimbine.[5]

Yohimbine blocks the pre- and post-synaptic α2 receptors. Blockade of post-synaptic α2 receptors causes only minor corpus cavernosum smooth muscle relaxation, due to the fact that the majority of adrenoceptors in the corpus cavernosum are of the α1 type. Blockade of pre-synaptic α2 receptors facilitates the release of several neurotransmitters in the central and peripheral nervous system — thus in the corpus cavernosum — such as nitric oxide and norepinephrine. Whereas nitric oxide released in the corpus cavernosum is the major vasodilator contributing to the erectile process, norepinephrine is the major vasoconstrictor through stimulation of α1 receptors on the corpus cavernosum smooth muscle. Under physiologic conditions, however, nitric oxide attenuates norepinephrine vasoconstriction.[25]

Botanical sources of yohimbine; sustainability[edit]

Pausinystalia yohimbe[edit]

The traditional source of yohimbine is the bark of the African tree P. yohimbe.   It has other uses, but the tree is sought out primarily for its bark; in practice, harvesting the bark kills the tree. Tree density is relatively low (average ≈ 4 harvestable trees/hectare), the high demand for medicines based on the bark has led to the tree's over-exploitation. The bark is traded in local markets and, because it is scarce, it is often adulterated with that of other species which contain little yohimbine.[26] The species is becoming endangered.[27]

Aspinosperma quebracho-blanco[edit]

Aspidosperma quebracho-blanco is an unrelated tree whose common name is quebracho blanco.[28] It is found in large areas of central South America, particularly the Gran Chaco, where it is often the dominant species in the canopy.[29] It is one of the most widely distributed Argentine arboreal species.[30][31] Traditionally it was logged for fuel, timber  and railway sleepers.[32] While in recent times cattle ranching and soya cultivation have led to considerable habitat loss,[33] and while there is still illegal logging, no shortage of the bark is reported. The tree has not been described as endangered: a few members of the genus Aspidosperma are on the IUCN Red List. but the quebracho blanco species is not one of them.[34]

In its bark an alkaloid is found which bears the name Quebrachine.   In 1914, two scientific papers claimed quebrachine was chemically identical to yohimbine.[35] This was disputed,[36] and the matter long remained in doubt.[37] However, in 1972, Effler and Effler using modern analytical techniques, including mass spectrometry, UV absorption,  IR absorption and NMR, established that quebrachine and yohimbine are one and the same thing.  They wrote:

While it was almost unthinkable in 1914 ... that the same alkaloid was formed in [completely] different plants, recent studies have shown that this is certainly the case for indole alkaloids.[38]

A range of secondary reference works give 'quebrachine' as a synonym for yohimbine.[39]

Strictly speaking, wrote George Barger FRS, yohimbine should have been have been given the scientific name quebrachine, seeing that it was first isolated from the quebracho tree and first named in the scientific literature. However the later work on P. yohimbe was better known, so the newer name stuck.[40]

See also[edit]


  1. ^ Hedner, T; Edgar, B; Edvinsson, L; Hedner, J; Persson, B; Pettersson, A (1992). "Yohimbine pharmacokinetics and interaction with the sympathetic nervous system in normal volunteers". European Journal of Clinical Pharmacology. 43 (6): 651–656. doi:10.1007/BF02284967. PMID 1493849.
  2. ^ yohimbine. (n.d.) Collins English Dictionary – Complete and Unabridged. (1991, 1994, 1998, 2000, 2003). Retrieved January 27, 2015 from http://www.thefreedictionary.com/yohimbine
  3. ^ a b Andersson KE (September 2001). "Pharmacology of penile erection". Pharmacological Reviews. 53 (3): 417–50. PMID 11546836.
  4. ^ a b Beille, P. E. (2013). "Scientific Opinion on the evaluation of the safety in use of Yohimbe (Pausinystalia yohimbe)". EFSA Journal. 11 (7): 3302. doi:10.2903/j.efsa.2013.3302.
  5. ^ a b Cohen, Pieter A.; Wang, Yan-Hong; Maller, Gregory; DeSouza, Renan; Khan, Ikhlas A. (March 2016). "Pharmaceutical quantities of yohimbine found in dietary supplements in the USA". Drug Testing and Analysis. 8 (3–4): 357–369. doi:10.1002/dta.1849.
  6. ^ 21 CFR Sec. 522.2670 Yohimbine
  7. ^ a b "Yohimbe Supplement". National Center for Complementary and Integrative Health. Retrieved 2017-08-28.
  8. ^ Kew World Checklist of Selected Plant Families, Pausinystalia johimbe
  9. ^ Year Book of the American Pharmaceutical Association. American Pharmaceutical Association. 1914. p. 564. Retrieved 2015-05-04.
  10. ^ Witkop, Bernhard (1943). "Zur Konstitution des Yohimbins und seiner Abbauprodukte". Justus Liebig's Annalen der Chemie. 554 (1): 83–126. doi:10.1002/jlac.19435540108. ISSN 0075-4617.
  11. ^ Liebig, Justus (1988). The Alkaloids: Chemistry and Pharmacology. Academic Press. p. 564. ISBN 978-0-12-469532-0.
  12. ^ van Tamelen; E. E. (1958). "The Total Synthesis of Yohimbine". J. Am. Chem. Soc. 80 (18): 5006–5007. doi:10.1021/ja01551a062.
  13. ^ Herle, B. (2011). "Total Synthesis of (+)-Yohimbine via an Enantioselective Organocatalytic Pictet–Spengler Reaction". J. Org. Chem. 76 (21): 8907–8912. doi:10.1021/jo201657n. PMID 21950549.
  14. ^ a b c Millan MJ, Newman-Tancredi A, Audinot V, et al. (February 2000). "Agonist and antagonist actions of yohimbine as compared to fluparoxan at alpha(2)-adrenergic receptors (AR)s, serotonin (5-HT)(1A), 5-HT(1B), 5-HT(1D) and dopamine D(2) and D(3) receptors. Significance for the modulation of frontocortical monoaminergic transmission and depressive states". Synapse. 35 (2): 79–95. doi:10.1002/(SICI)1098-2396(200002)35:2<79::AID-SYN1>3.0.CO;2-X. PMID 10611634.
  15. ^ "PDSP Ki Database".
  16. ^ a b Arthur JM, Casañas SJ, Raymond JR (June 1993). "Partial agonist properties of rauwolscine and yohimbine for the inhibition of adenylyl cyclase by recombinant human 5-HT1A receptors". Biochemical Pharmacology. 45 (11): 2337–41. doi:10.1016/0006-2952(93)90208-E. PMID 8517875.
  17. ^ a b Kaumann AJ (June 1983). "Yohimbine and rauwolscine inhibit 5-hydroxytryptamine-induced contraction of large coronary arteries of calf through blockade of 5 HT2 receptors". Naunyn-Schmiedeberg's Archives of Pharmacology. 323 (2): 149–54. doi:10.1007/BF00634263. PMID 6136920.
  18. ^ a b Baxter GS, Murphy OE, Blackburn TP (May 1994). "Further characterization of 5-hydroxytryptamine receptors (putative 5-HT2B) in rat stomach fundus longitudinal muscle". British Journal of Pharmacology. 112 (1): 323–31. doi:10.1111/j.1476-5381.1994.tb13072.x. PMC 1910288. PMID 8032658.
  19. ^ "Yohimbine (PIM 567)". Inchem.org. Retrieved 2013-05-26.
  20. ^ National Institute of Mental Health. "PDSP Ki Database". University of North Carolina. Archived from the original on November 8, 2013. Retrieved 5 July 2013.
  21. ^ "Yohimbine". DrugBank. University of Alberta. Archived from the original on January 30, 2013. Retrieved 12 April 2014.
  22. ^ Singewald, N; Schmuckermair, C; Whittle, N; Holmes, A; Ressler, KJ (May 2015). "Pharmacology of cognitive enhancers for exposure-based therapy of fear, anxiety and trauma-related disorders". Pharmacology & Therapeutics. 149: 150–90. doi:10.1016/j.pharmthera.2014.12.004. PMC 4380664. PMID 25550231.
  23. ^ McGuire, JF; Lewin, AB; Storch, EA (August 2014). "Enhancing exposure therapy for anxiety disorders, obsessive-compulsive disorder and post-traumatic stress disorder". Expert Review of Neurotherapeutics. 14 (8): 893–910. doi:10.1586/14737175.2014.934677. PMC 4125602. PMID 24972729.
  24. ^ FDA regulations on OTC products
  25. ^ Saenz De Tejada, I; Kim, NN; Goldstein, I; Traish, AM (2000). "Regulation of pre-synaptic alpha adrenergic activity in the corpus cavernosum". International Journal of Impotence Research. 12 Suppl 1: S20–25. doi:10.1038/sj.ijir.3900500. PMID 10845761.
  26. ^ Jiofack Tafokou, R.B. (2012). "Pausinystalia johimbe". In Lemmens; Louppe; Oteng-Amoako. Timbers 2: Volume 7 of Plant Resources of Tropical Africa. Wageningen, Ne: PROTA Foundation. pp. 516–519. ISBN 9290814950.
  27. ^ Rao, M.R.; Palada, M.C.; Becker, B.N. (2013). "Medicinal and aromatic plants in agroforestry systems". In Nain, P.K.R.; Rao, M.R.; Buck, L.E. New Vistas in Agroforestry: A Compendium for  the 1st World Congress of Agroforestry, 2004. 1. Springer Science and Business Media. p. 109. ISBN 9401724245.
  28. ^ "Quebracho" is formed from the Spanish words for "axe breaker'.
  29. ^ Bucher, E.H. (2012). "Chaco and Caatinga — South American Arid Savannas, Woodlands and Thickets". In Huntley, B.J.; Walker, B.H. Ecology of Tropical Savannas. Ecological Studies. 42. Springer Science and Business. Media. pp. 54–57. ISBN 3642687865.
  30. ^ "Nombre científico: Aspidosperma quebracho-blanco". Herbario Digital (in Spanish). CONICET. Retrieved 12 January 2019.
  31. ^ Moglia, Juana Graciela; López, Carlos Raul (2001). "Variabilidad radial de algunos caracteres anatómicos de Aspidosperma quebracho blanco". Bosque (in Spanish). Universidad Austral de Chile. 22 (2): 4. ISSN 0304-8799.
  32. ^ Moglia, Juana Graciela; López, Carlos Raul (2001). "Variabilidad radial de algunos caracteres anatómicos de Aspidosperma quebracho blanco". Bosque (in Spanish). Universidad Austral de Chile. 22 (2): 4. ISSN 0304-8799.
  33. ^ Kent, Robert B. (2006). Latin America: Regions and People. Texts in regional geography. Guilford Press. p. 151. ISBN 1572309091.
  34. ^ "The IUCN Red List of Threatened Species". Retrieved 12 January 2019.
  35. ^ Barger, George; Field, Ellen (1915). "Yohimbine (Quebrachine)". Journal of the Chemical Society, Transactions. 107: 1025.
  36. ^ Allen, Alfred Henry; Sadler, Samuel Schmucker; Lathrop, Elbert C.; Mitchell, C. Ainsworth (1929). Allen's Commercial Organic Analysis. Philadelphia: P. Blakiston's Son & Co. p. 217.
  37. ^ Moyano Navarro, Belzor (1942). "QUEBRACHINA Y YOHIMBINA: EFECTOS SOBRE LA CORRIENTE DE ACCIÓN DEL CORAZÓN". Revista de la Universidad Nacional de Córdoba (in Spanish). Córdoba, Argentina: Universidad Nacional de Córdoba: 369–403.. ('Quebrachine' and 'yohimbine' had different effects on the heart in the dog model; but the suppliers of those reagents were trusted to vouch for their authenticity.)
  38. ^ Effler, E.H.; Effler, A.H. (1972). "Ûber die Identitat von Quebrachin und Yohimbin". Chemischer Informationsdienst (in German). Pharmakologischen Institut der Universitat Heidelberg. 4 (14): 921–924.
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  40. ^ Barger, George; Field, Ellen (1915). "Yohimbine (Quebrachine)". Journal of the Chemical Society, Transactions. 107: 1025.