OTTAWA - Health Canada is advising Canadians about new safety information for carbamazepine, a drug used to treat epilepsy, mania, bipolar disorder and a painful condition of the face called trigeminal neuralgia. In Canada, carbamazepine is sold under the brand name Tegretol, and multiple generic names.
Health Canada has revised the prescribing information for Tegretol, and is currently revising the prescribing information for all generic carbamazepine products to include information about an increased risk of serious skin reactions for patients of Asian ancestry, as compared to patients of non-Asian ancestry. Novartis Pharmaceuticals Canada, the manufacturer of Tegretol in Canada, has issued a letter to health care professionals to inform them of the new safety information.
Serious and sometimes fatal skin reactions known as Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) have been known to occur very rarely with carbamazepine. While all patients treated with carbamazepine are at risk for these serious skin reactions, the risk is approximately 10 times higher in Asian countries than in Western countries. In addition, studies have suggested that patients of Asian ancestry may also be at increased risk if they take carbamazepine.
There is a genetic test that may be useful in identifying a particular genetic marker in patients of Asian ancestry. This marker has been linked to an increased risk of developing serious skin reactions to carbamazepine. Patients of Asian - particularly Han Chinese - ancestry may wish to discuss this test with their doctors as a possible screening tool to determine if they are at increased risk of serious skin reactions.
All patients taking carbamazepine - including those who have had the genetic test done, and regardless of their ethnicity - should immediately consult a physician if they develop any signs of serious skin reactions such as a rash, red skin, blistering of the lips, eyes or mouth, or peeling skin with an accompanying fever.
Patients who have been taking carbamazepine for more than a few months without developing skin reactions are at low risk of these events ever developing from carbamazepine.
Patients who have previously had serious skin reactions during treatment with carbamazepine, regardless of ethnicity, should not take carbamazepine again and should consult their health care professional as soon as possible so that a decision can be made regarding alternative treatments.
Patients taking carbamazepine should not stop treatment before speaking with their doctor.
The prescribing information for all generic carbamazepine-containing products is being revised to include the same new safety information for serious skin reactions that has been added to the Tegretol prescribing information. The following is a list of carbamazepine-containing products being sold in Canada. Each product may have multiple formulations, including tablets, suspension, chewtabs, or controlled release:
- Apo-carbamazepine (Apotex Incorporated)
- Bio-carbamazepine (Biomed 2002 Inc.)
- Carbamazepine (Pro Doc Limitée)
- Dom-carbamazepine (Dominion Pharmacal)
- Gen-carbamazepine (Genpharm ULC)
- Mazepine (Valeant Canada Limitée/Limited )
- Novo-carbamaz (Novopharm Limited)
- Nu-carbamazepine (Nu-Pharm Inc.)
- PHL-carbamazepine (Pharmel Inc.)
- PMS-carbamazepine (Pharmascience Inc.)
- Sandoz-carbamazepine (Sandoz Canada Incorporated)
- Taro-carbamazepine (Taro Pharmaceuticals Inc.)
- Tegretol (Novartis Pharmaceuticals Canada Inc.)
Consumers requiring more information about this advisory can contact Health Canada's public enquiries line at (613) 957-2991, or toll free at 1-866-225-0709.
To report a suspected adverse reaction to these health products, please contact the Canada Vigilance Program of Health Canada by one of the following methods:
Canada Vigilance Program
Marketed Health Products Directorate
Ottawa, Ontario, AL 0701C
The Canada Vigilance adverse reaction reporting form, including a version that can be completed and submitted online, is located in the MedEffect area of the Health Canada Web site.
tag: Health Canada, Drug Advisory, carbamazepine, epilepsy, mania, bipolar disorder, trigeminal neuralgia, Tegretol, Novartis Pharmaceuticals Canada, Stevens-Johnson Syndrome, Toxic Epidermal Necrolysis