Hi-Tech Pharmaceuticals and the FDA have notified healthcare professionals and consumers of a nationwide recall of all products sold under the name Stamina-Rx.
An FDA lab analysis found that the product contained the undeclared ingredient, benzamidenafil. Benzamidenafil is in the same pharmacologic class as the phosphodiesterase type 5 (PDE5) inhibitors sildenafil, tadalafil, and vardenafil, that are FDA-approved for the treatment of erectile dysfunction (ED). Benzamidenafil is not FDA-approved and poses a threat to consumers because it may interact with nitrates found in some prescription drugs (eg, nitroglycerin) and may lower blood pressure to dangerous levels. Patients with diabetes, high blood pressure, high cholesterol, or heart disease often take nitrates and may be the most susceptible to adverse effects from this product.
Source here.