Erectile dysfunction yohimbine

Yohimbine (4.43) is an antagonist. Yohimbine, an indole alkaloid closely related to reserpine—an a antagonist—has been evaluated as a potential treatment for male erectile dysfunction. Naphazoline (4.46) and other a-agonist imidazoline compounds are nasal decongestants, used by inhalation to decrease swelling of the nasal mucosa. Overdependence on and overuse of these drugs can lead to rebound swelling. 

Yohimbine Blocks k2 elicits increased central sympathetic activity increased norepinephrine release Raises BP and HR Male erectile dysfunction hypotension May cause anxiety excess pressor effect if norepinephrine transporter is blocked... 

Erectile dysfunction in men has long been the subject of research (by both amateur and professional scientists). Among the substances used in the past and generally discredited are "Spanish Fly" (a bladder and urethral irritant), yohimbine (an a2... 

A patient with CREST syndrome (calcinosis, Raynaud s phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasia) paradoxically experienced worsening of Raynaud s phenomenon when using yohimbine for erectile dysfunction (6). 

Ernst E, Pittler MH. Yohimbine for erectile dysfunction a systematic review and meta-analysis of randomized clinical trials. J Urol 1998 159(2) 433-6. 

Johnson S, lazzetta J, Dewar C. Severe Raynaud s phenomenon with yohimbine therapy for erectile dysfunction. J Rheumatol 2003 30(ll) 2503-5. 

Yohimbine is well tolerated at the oral doses used for erectile dysfunction. The main side effects are nausea, dizziness, and nervousness. Headache and skin flushing have also been reported. Yohimbine has no significant effect on jS-adrenergic receptors, and its effect on blood pressure has not been adequately evaluated. Common side effects after parenteral administration include sweating, nausea, and vomiting. Yohimbine penetrates the blood-brain barrier and can produce a complex pattern of responses (93). The central effects include anti-diuresis, a general picture of central excitation including elevated blood pressure and heart rate, increased motor activity, irritability, and tremor. 

Teloken C, Rhoden EL, Sogari R et al. Therapeutic effects of high-dose yohimbine hydrochloride on organic erectile dysfunction. J Urol 1998 159 122-124. 

Other intracorporal agents used to induce penile erections include papaverine, a drug with a relaxant effect on smooth muscle, and phentolamine, an a-adrenergic receptor blocker. Yohimbine, an a2-adrenoreceptor antagonist, enhances noradrenergic neurotransmission and may improve erectile dysfunction via adrenergic system activation. 

The final three indole-containing drugs approved for animals in the U.S. are indole alkaloids. Metoserpate 6 is a water-soluble reserpine alkaloid given to reduce stress and prevent hysteria in poultry. Yohimbine 7 is a central alpha-2 adrenergic antagonist. It is used in dogs to reverse the anesthesia produced by the commonly used anesthetic Xylazine. Strychnine 8 is a rodenticide (Scheme 10). There is no current approved human medical use for metoserpate although yohimbine is prescribed for erectile dysfunction. Strychnine, once used in small doses as a laxative... 

Yohimbine causes the blocking of the 02 receptor of the sympathetic nerve, and inhibits the separation of NE from the receptor ending. As a result, extension of the blood vessels in tbe skin and mucous membranes, and especially of tbe external genitals, occurs. Tbis alkaloid is also said to possess an activity to stimulate the central nervous system and cause priapism. That is why this alkaloid is used for erectile dysfunction but the effective dose is only one-third of the toxic dose. 

In a recent study, the bark extract has been demonstrated to bind with high affinity to human penile alpha2 adrenoreceptors and with less affinity to the alphai receptor. The authors results provide support for the use of quebracho in erectile dysfunction and they attributed the reported activity to yohimbine present in the extract. Aspidospermine and quebrachamine were also found to be similar to yohimbine in possessing adrenergic blocking activities in various urogenital tissues. ... 

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