Zyrexin Vs Stamina Rx

Image by Flickr.com, courtesy of Shutr

When considering any type of supplement use for a medical condition like erectile dysfunction, doctor consultation is first advised to rule out other medical reasons for the problem.

Those with existing heart disease, high blood pressure and other serious health conditions may need to avoid supplement use altogether due to potential adverse interactions with other prescription drugs.

Erectile Dysfunction

Image by Flickr.com, courtesy of Gordana Adamovic-Mladenovic

Erectile dysfunction is a condition in which a man is unable to maintain an erection long enough to complete the act of sex. While Viagra and other prescription medications are available to help medically, according to the Mayo Clinic, non-prescription herbal treatments are also littering the marketplace as well.

These supplements include an herb known as L-arginine, which is used as one component of Zyrexin, an herbal erectile dysfunction alternative medicine (see Mayo link in Ref. Section below) and the drug benzamidenafil---found to be in the supplement Stamina Rx, without the approval of the U.S. Food and Drug Administration (FDA).


The herbal supplement Zyrexin claims to help eliminate erectile dysfunction in three ways: by increasing brain chemical messengers to the alpha-2 adrenergic system (increasing libido), by providing an L-arginine pharmaceutical-derived source of nitric oxide (increasing blood flow to the penis) and the elevation of norepinephrine through compounds in Zyrexin (to maintain erection).

L-arginine has the possibility of lowering blood pressure, according to the Mayo Clinic, which can be a potential negative side effect of this medication in some men. In addition, nausea, diarrhoea and abdominal cramps are possible side effects as well. This is especially true when L-arginine is taken in high dosages.

Stamina Rx

In June of 2009, Stamina Rx, manufactured by NVE, Incorporated, was involved in an FDA recall due to the presence of an undeclared ingredient in the supplement: benzamidenafil. Supplements must disclose all ingredients to the FDA at time of manufacture to avoid potential recalls and must not contain any drugs.

The drug benzamidenafil (not an herb) is in the same class of drugs that are recognised (and approved) by the FDA in the treatment of erectile dysfunction: sildenafil, tadalafil and vardenafil. However, benzamidenafil has never been approved for erectile dysfunction use by the FDA and has the potential to adversely interact with nitrates in other prescribed medications and---like Zyrexin---could lower blood pressure too.


Consumers with Stamina Rx in their possession are urged to stop using it immediately, according to Drugs.com. This is especially true for individuals who also take nitroglycerine or are diabetic, have high cholesterol and blood pressure or heart disease.


The U.S. Food and Drug Administration does not formally approve herbal supplements or test them prior to their manufacture. Therefore, unless a consumer experiences an adverse side effect---or the FDA is notified of a potential dangerous ingredient present in a supplement---individuals are relying solely on the integrity of the supplement manufacturer and packaging company to provide them with a safe product.