Health Canada is warning consumers not to use a certain Chinese herbal impotency product containing tadalafil, because it may cause severe adverse reactions.

The tablet - called Hua Fo VIGOR-MAX - contains tadalafil which is similar to the drug used in Viagra, sildenafil.

Tadalafil is a prescription drug approved for sale in the U.K., Germany, Sweden, Denmark, Finland, New Zealand, Australia and Singapore. However, tadalafil is not approved for sale in Canada.

Health Canada says the drug should not be used in conjunction with products containing nitrates. This mixture could cause the development of potentially life-threatening low blood pressure.

The drug also should not be used by patients with severe kidney or liver problems.

Hua Fo is made in China and sold in Canada by Shenlong Natural International Inc.

The herbal sexual enhancers are red coloured tablets packaged in white plastic bottles.

A red label reads:

  • 300 mg. 30 tablets.
  • Lot Number 5444 Exp DE2007
  • Dosage: For adults only, take 5 tablets one hour before intercourse