Contents

Yohimbine

Yohimbine

Clinical data
Routes of administration	Oral
ATC code	G04BE04 (WHO) QV03AB93 (WHO)
Legal status
Legal status	In general: Over-the-counter (OTC)
Identifiers
IUPAC name 17α-hydroxy-yohimban-16α- carboxylic acid methyl ester
CAS Number	146-48-5
PubChem CID	8969
IUPHAR/BPS	102
ChemSpider	8622 Y
UNII	2Y49VWD90Q
ChEMBL	ChEMBL15245 N
CompTox Dashboard (EPA)	DTXSID9040130
ECHA InfoCard	100.005.157
Chemical and physical data
Formula	C21H26N2O3
Molar mass	354.44 g/mol (base) 390.90 g/mol (hydrochloride) g·mol−1
3D model (JSmol)	Interactive image
SMILES O=C(OC)[C@@H]5[C@H]4C[C@H]3c2nc1ccccc1c2CCN3C[C@@H]4CC[C@@H]5O
InChI InChI=1S/C21H26N2O3/c1-26-21(25)19-15-10-17-20-14(13-4-2-3-5-16(13)22-20)8-9-23(17)11-12(15)6-7-18(19)24/h2-5,12,15,17-19,22,24H,6-11H2,1H3/t12-,15-,17-,18-,19+/m0/s1 Y Key:BLGXFZZNTVWLAY-SCYLSFHTSA-N Y
NY (what is this?)  (verify)

Yohimbine is an alkaloid with stimulant and aphrodisiac effects found naturallyinPausinystalia yohimbe (Yohimbe). It is also found naturally in Rauwolfia serpentina (Indian Snakeroot), along with several other active alkaloids. Yohimbine has been used as both an over-the-counter dietary supplementinherbal extract form and prescription medicine in pure form for the treatmentofsexual dysfunction. Yohimbine was explored as a remedy for type 2 diabetes in animal and human models carrying polymorphisms of the α_2A-adrenergic receptor gene.^[1]

Indications

Sexual

The NIH states that yohimbine hydrochloride is the standardized form of yohimbine that is available as a prescription medicine in the United States, and has been shown in human studies to be effective in the treatment of male impotence.^[2]

Yohimbine Hydrochloride, USP—a standardized form of yohimbine—is a prescription medicine that has been used to treat erectile dysfunction.^[3] Controlled studies suggest that it is not always an effective treatment for impotence, and evidence of increased sex drive (libido) is anecdotal only.^[4]

It cannot be excluded that orally administered yohimbine can have a beneficial effect in some patients with ED. The conflicting results available may be attributed to differences in drug design, patient selection, and definitions of positive response. However, generally, available results of treatment are not impressive.^[5]

Yohimbine has been shown to be effective in the reversal of sexual satiety and exhaustion in male rats.^[6] Yohimbine has also been shown to increase the volume of ejaculated semen in dogs, with the effect lasting at least five hours after administration.^[7] Yohimbine has been shown to be effective in the treatment of orgasmic dysfunction in men.^[8]

Fat loss

According to one study, oral yohimbine supplementation may actuate significant fat loss in athletes.^[9] Numerous bodybuilding supplement companies sell formulations of yohimbine for transdermal delivery to effect a local reduction of adipose tissue, although there the experimental evidence for its efficacy is limited.^[10][11]

Other uses

Yohimbine has also been used for the treatment of sexual side effects caused by some antidepressants (SSRIs), female hyposexual disorder, as a blood pressure boosting agent in autonomic failure, xerostomia, and as a probe for noradrenergic activity.

The addition of yohimbine to fluoxetineorvenlafaxine has also been found to potentiate the antidepressant action of both of these agents.^[12]

Yohimbine has been used to facilitate recall of traumatic memories in the treatment of post traumatic stress disorder (PTSD).^[13] Use of yohimbine outside therapeutic settings may not be appropriate for persons suffering from PTSD.^[14] In pharmacology, yohimbine is used as a probe for α₂-adrenoceptor. In veterinary medicine, yohimbine is used to reverse anesthesia from the drug xylazine in small and large animals.

Pharmacology

Yohimbine has high affinity for the α₂-adrenergic receptor, moderate affinity for the α₁-adrenergic, 5-HT_1A, 5-HT_1B, 5-HT_1D, 5-HT_1F, 5-HT_2B, and D₂ receptors, and weak affinity for the 5-HT_1E, 5-HT_2A, 5-HT_5A, 5-HT₇, and D₃ receptors.^[15][16] It behaves as an antagonist at α₁-adrenergic, α₂-adrenergic, 5-HT_1B, 5-HT_1D, 5-HT_2A, 5-HT_2B, and D₂, and as a partial agonist at 5-HT_1A.^{[15][17][18][19]} Its intrinsic activities at the other sites listed are unclear/unknown but it is probably mostly antagonistic at them.

Production

Yohimbine is the principal alkaloid of the bark of the West African evergreen Pausinystalia yohimbe (formerly Corynanthe yohimbe), family Rubiaceae (Madder family). There are 31 other yohimbane alkaloids found in Yohimbe. In Africa, yohimbe has traditionally been used as an aphrodisiac.^[3] However, it is very important to note that while the terms yohimbine, yohimbine hydrochloride, and yohimbe bark extract are related, they are not interchangeable.^[2]

The main active chemical present in yohimbe bark is yohimbine HCl (indole alkaloid), found in the bark of the Pausinystalia yohimbe tree.

However, the levels of yohimbine that are present in yohimbe bark extract are variable and often very low.^[2] Therefore, although yohimbe bark has been used traditionally to reduce male erectile dysfunction, there is not enough scientific evidence to form a definitive conclusion in this area.

Adverse effects

Yohimbine has significant side effects, such as anxiety reactions. According to the Mayo Clinic, yohimbine can be dangerous if used in excessive amounts.^[20]

Higher doses of oral yohimbine may create numerous side effects, such as rapid heart rate, high blood pressure, overstimulation, insomnia and/or sleeplessness. Some effects in rare cases were panic attacks, hallucinations, headaches, dizziness, and skin flushing.^[21]

More serious adverse effects may include seizures and renal failure. Yohimbine should not be consumed by anyone with liver, kidney, heart disease, or a psychological disorder.^[21]

The therapeutic index of yohimbine is quite low; the range between an effective dose and a dangerous dose is very narrow.^[21] This may also lead to precipitation of panic disorder type reactions.

Yohimbine in combination with modafinil causes dangerous acute rapid heart beat and acute increased blood pressure.

See also

• Ajmalicine
• Corynanthine
• Rauwolscine
• Reserpine
• Deserpidine
• Rescinnamine

References

External links

• "Yohimbe bark extract" (MedlinePlus)
• Effectiveness Rating and Review of Yohimbe by Pharmacists