Herbal Viagra and Cocaine: A Match Made in Hell

OCTOBER 18, 2015
A recent high-profile case of a celebrity allegedly indulging in “Herbal Viagra” and cocaine has piqued the interest of the general public and highlighted an often-overlooked problem for pharmacists. Lamar Odom’s alleged drug overdose spotlights the potential danger of combining readily available herbal products with any drug, illicit or not.

Herbal Viagra is generally used as a catchall term for unapproved products advertised as sexual performance enhancers. Patients often use these products to treat impotence or erectile dysfunction; however, none of them are FDA approved, and studies have failed to show meaningful efficacy.
 
The products that are especially dangerous contain the stimulant yohimbine, an alkaloid that comes from the bark of a tree native to Africa. Yohimbine is a common ingredient in many other herbal remedies, such as supplements for weight loss and depression.
 
The mechanism by which yohimbine exerts its sympathomimetic effect is believed to involve its ability to block central inhibitory alpha2-receptors, leading to the increased release of excitatory neurotransmitters such as norepinephrine.1 This ultimately increases blood pressure, heart rate, and (according to some) penile blood flow.2,3

Yohimbine can interact with various prescription and non-prescription drugs.4 Worse still, amounts of active yohimbine vary from product to product.
 
Because there is no standardization or regulation of yohimbine in herbal preparations, its physiological effects can vastly differ between products. Unfortunately, it is often marketed as a nutraceutical product that may not be perceived as a “real drug” by many patients.
 
This combined with the fact that the product is often used to treat sexual dysfunction makes it a problem for pharmacists, since many patients do not report taking yohimbine or supplements that contain it. As a result, catching potential drug-drug interactions involving yohimbine can be very difficult.  

Yohimbine has been shown to inhibit monoamine oxidase and can interact with other monoamine oxidase inhibitors. Its alpha2-receptor antagonism can render alpha2-agonist therapy with a drug such as clonidine less effective.
 
The sympathomimetic effect of yohimbine can further exacerbate the cardiovascular effects of other stimulants such as caffeine or cocaine. Odom’s adverse event while taking cocaine and Herbal Viagra highlights the potential danger of combining herbal remedies and other drugs.
 
While the role that the herbal products may have played in Odom’s alleged near-death experience is not yet known, it does represent a potentially dangerous combination. 
 
On its own, cocaine can elevate blood pressure as well as the risk for experiencing adverse cardiovascular events.5 Yohimbine taken alone is also known to elevate blood pressure, and the FDA has warned of its harmful effects.6
 
Therefore, combining the 2 drugs may lead to an even greater risk of experiencing a cardiovascular event.
 
Studies conducted in dogs showed that concurrent yohimbine and cocaine use can cause a greater increase in blood pressure compared with either substance administered separately. The authors concluded that the alpha-blocking effects of the yohimbine can increase the risk of cardiovascular toxicity when combined with cocaine.7

It is not yet clear whether Lamar Odom was indeed taking an herbal supplement that contains yohimbine or whether it was a contributing factor to the adverse event that he experienced. But what is clear is that many herbal ingredients pose risks to those who take such products.
 
Unfortunately, it often takes a tragedy to highlight this danger, and this case is no different.
 
It is very important for pharmacists to be aware of the dangers posed by Herbal Viagra and to discourage the use of these products. These products have no established benefit and carry excessive risk to patients who use them. 
 
Pharmacists should continue to play an active role in educating patients about the dangers of herbal products used to treat sexual dysfunction. Hopefully, the current spotlight on these products will spread awareness of their dangers and ultimately reduce these unfortunate incidences. 

References
1. Millan MJ, Newman-Tancredi A, Audinot V, Cussac D, Lejeune F, Nicolas JP, Coge F, Galizzi JP, Boutin JA, Rivet JM and others. 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. 2000;35(2):79-95.
2. Hedner T, Edgar B, Edvinsson L, Hedner J, Persson B, Pettersson A. Yohimbine pharmacokinetics and interaction with the sympathetic nervous system in normal volunteers. European Journal of Clinical Pharmacology. 1992;43(6):651-656.
3. Clinical Pharmacology [database online]. Tampa, FL: Gold Standard, Inc. 2015. http://www.clinicalpharmacology.com. Updated April, 2014. 2015.
4. Tachjian A, Maria V, Jahangir A. Use of Herbal Products and Potential Interactions in Patients With Cardiovascular Diseases. Journal of the American College of Cardiology. 2010;55(6):515-525.
5. Schwartz BG, Rezkalla S, Kloner RA. Cardiovascular effects of cocaine. Circulation. 2010;122(24):2558-69.
6. Dietary supplements. FDA. http://www.fda.gov/Food/DietarySupplements/default.htm. 2015.
7. Wilkerson RD. Cardiovascular effects of cocaine: enhancement by yohimbine and atropine. J Pharmacol Exp Ther. 1989;248(1):57-61.

Erik Hefti, PharmD, MS, PhD
Erik Hefti, PharmD, MS, PhD
Erik Hefti holds a PharmD as well as a Master's and PhD degrees in pharmaceutical science from the University at Buffalo. His research focus is pediatric pharmacogenomic factors impacting cardiovascular toxicity following cancer chemotherapy and genetic testing utilization to optimize healthcare outcomes. He is currently practicing as a clinical pharmacist at Sisters of Charity Hospital, St. Joseph Campus in Buffalo, NY.
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