Consumers should not use two e-cigarette liquids that contain erectile dysfunction drugs because they may pose health risks, the U.S. Food and Drug Administration said Tuesday.

The two HelloCig e-liquids contain tadalafil and sildenafil, the main ingredients in two of the most popular male enhancement drugs (Cialis and Viagra) on the market, according to the FDA, CNN reported.

Lab tests found both sildenafil and tadalafil in E-CialisHelloCig E-Liquid and sildenafil in E-Rimonabant HelloCig E-Liquid. The e-liquids are made by HelloCig Electronic Technology Co. Ltd. of Shanghia, China.

"These FDA-approved prescription drugs are not approved for inclusion in e-liquid products sold over the counter and are therefore being sold illegally," the FDA said.

Because the products are not properly labeled, they could pose a risk to people who take nitrates for high blood pressure, diabetes, high cholesterol or heart disease.

The undeclared ingredients in the e-liquids "may interact with nitrates found in some prescription drugs such as nitroglycerin and may lower blood pressure to dangerous levels," according to the FDA, CNNreported.

No adverse events related to the two e-cigarette liquids have been reported to the FDA.