Tian Li, a sexual enhancement product, contains an untested compound and a prescription medication, both of which could cause serious problems for patients with heart disease, Health Canada said.

The British Medicines and Healthcare products Regulatory Agency said Tian Li contains tadalafil and hydroxyhomosildenafil.

Hydroxyhomosildenafil has not been reviewed to determine its safety and efficacy, but is similar to sildenafil, a prescription medication for erectile dysfunction. Tadalafil is also prescribed to treat erectile dysfunction.

Unsupervised use of the drugs could cause serious cardiovascular side-effects, including sudden cardiac death, in patients with heart disease.

Tadalafil and sildenafil should not be used by people taking nitrate drugs because of the risk of developing potentially life-threatening low blood pressure.