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Public advisory

Authorized natural health product (Prema G) contains hidden dangerous ingredient

Starting date:
August 23, 2013
Posting date:
August 23, 2013
Type of communication:
Natural health products
Source of recall:
Health Canada
Undeclared Substance
General Public
Identification number:


After being stopped at the border, an authorized natural health product, Prema G (Granules packaged in tea packets, NPN: 80035944) was tested by Canada Border Services Agency and found to contain a hidden ingredient (hydroxyhomosildenafil thione) that may pose serious risks to the health of Canadians.

Prema G was authorized by Health Canada but not with the ingredient, hydroxyhomosildenafil thione. Hydroxyhomosildenafil thione is similar to sildenafil, which can be found in products promoted as sexual stimulants. Drugs authorized by Health Canada that contain these ingredients can only be sold with a prescription and by a pharmacy.

Products affected

Prema G (NPN: 80035944)

What you should do

  • Consult your healthcare practitioner with any questions or concerns regarding use of this product.
  • Report any adverse reactions potentially related to these products to Health Canada.
  • Contact Health Canada's toll-free line at 1-800-267-9675 with questions or complaints about this product.

Who is affected

Canadians who have purchased or used these products, particularly people with heart problems.


Sildenafil is a prescription medication that should only be used under the supervision of a health care practitioner. Products containing sildenafil or drugs similar to sildenafil (known as analogs) should never be used by individuals taking any kind of nitrate drug (e.g. nitroglycerine) as it can cause potentially life-threatening low blood pressure.

Individuals with heart problems including high blood pressure, a history of heart attack, stroke, abnormal heart beat or chest pain are at higher risk of cardiovascular side-effects if they engage in sexual activity, including if they use sildenafil to help them achieve an erection. Other possible side-effects of using sildenafil include headache, facial flushing, indigestion, dizziness, abnormal vision and hearing loss.

Report health or safety concerns

  • Call toll-free at 1-866-234-2345
  • Visit MedEffect Canada's web page on Adverse Reaction Reporting for information on how to report online, by mail or by fax.

Media enquiries

Health Canada
(613) 957-2983

Public enquiries

(613) 957-2991
1-866 225-0709

What Health Canada is doing

Health Canada is following up with the company to determine how this authorized product was found to contain hydroxyhomosildenafil thione, which could pose risks to the health and safety of Canadians. Health Canada is also taking steps to determine whether the adulterated product is currently being sold on the Canadian market. If Health Canada learns of any additional authorized products that are adulterated, actions will be taken to mitigate any risks to consumers.


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