By Naomi Thomas, CNN

(CNN) -- Due to a recent rise in reported health issues, the US Food and Drug Administration warned on Tuesday against using or purchasing Rhino male enhancement products.

Since 2007, the FDA said, it has identified more than 25 Rhino products, some with names such as Platinum Rhino 25000 and Krazzy Rhino 25000, that have hidden drug ingredients.

The FDA said the products are often sold in single-serving packages at locations such as gas stations and convenience stores, or through online retailers such as eBay and Amazon. Recently, the products have also been found in international mail shipments, the agency said.

In an email, eBay spokesman Ryan Moore said, "Product safety is important to eBay and we work hard to ensure our marketplace is free of harmful products. These types of items are prohibited under our policies, and therefore not allowed to be listed on the eBay market place." EBay regularly sweeps the site to remove such items, he said.

Amazon has not responded to a request for comment.

"Over the past few years, the FDA has been combatting the retail sale of male enhancement drug products that are frequently misrepresented as dietary supplements and that contain hidden and potentially harmful active drug ingredients," said Donald D. Ashley, director of the Office of Compliance at the FDA's Center for Drug Evaluation and Research.

According to the FDA, the "products contain undeclared ingredients that are the same as or structurally similar to active ingredients found in FDA-approved prescription drugs used to treat erectile dysfunction."

For example, some Rhino products contain the same active ingredient as Viagra and Cialis, sildenafil and/or tadalafil, respectively. These undeclared ingredients can lead to "significant safety issues and the risk of serious adverse events," the FDA said.

"The FDA has received reports of people experiencing chest pain, severe headaches and prolonged erections after taking a Rhino product that led to surgical intervention and hospitalization due to extreme drops in blood pressure," according to the agency.

People who experience negative health effects or have issues with the quality or safety of a dietary supplement can report it to the FDA's MedWatch Safety Information program. Products identified by the FDA as having hidden active drug ingredients can be found in the tainted products database.

Not all misrepresented products are included in the database, and consumers should still be wary, the FDA noted.

"Consumers should be cautious about using certain products, especially those promoted for sexual enhancement, weight loss, bodybuilding and/or pain relief. Consumers should also be on the alert for products that offer immediate or quick results and that sound too good to be true," the agency said.