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Archived – Important Information – Topamax (topiramate) – Janssen Othro Inc.

Starting date:
July 11, 2003
Posting date:
July 17, 2003
Type of communication:
Dear Healthcare Professional Letter
Drugs, Affects children, pregnant or breast feeding women
Source of recall:
Health Canada
Important Safety Information
Healthcare Professionals
Identification number:

This is duplicated text of a letter from Janssen-Ortho Inc.
Contact the company for a copy of any references, attachments or enclosures.

Notice about Health Canada advisories

[Text of letter begins]

Important Drug Safety Information

July 11, 2003

Subject: Reports of Oligohidrosis (decreased sweating) and Hyperthermia in patients treated with Topamax* (topiramate)

Dear Healthcare Professional:

Janssen-Ortho Inc., following discussions with Health Canada, would like to inform you of important safety information pertaining to rare reports, primarily in children, of oligohidrosis (decreased sweating) and hyperthermia in patients treated with Topamax (topiramate).

The Prescribing Information for Topamax was revised in February 2003. Additional changes, including relocation of information on oligohidrosis and hyperthermia to the Warnings and Precautions section, are being introduced at this time. Please carefully review the information noted below:

Safety information received to date indicates that oligohidrosis (decreased sweating) and hyperthermia, infrequently resulting in hospitalization, have been reported in topiramate-treated patients. Oligohidrosis and hyperthermia may have potentially serious sequelae and may be preventable by prompt recognition of symptoms and appropriate treatment. Decreased sweating and elevation of body temperature above normal characterized the cases reported in patients treated with topiramate. Some of the cases were reported after exposure to elevated environmental temperatures.

These reports have primarily involved children. Patients treated with Topamax, especially pediatric patients, should be monitored closely for evidence of decreased sweating and increased body temperature, particularly in hot weather. Proper hydration before and during activities such as exercise or exposure to warm temperatures is recommended.

Caution should be used when TOPAMAX is prescribed with other drugs that predispose patients to heat-related disorders; these drugs include, but are not limited to, other carbonic anhydrase inhibitors and drugs with anticholinergic activity.

Background Information

Clinical Trial Data:
As of February 2002, the reporting rate of all potential cases of oligohidrosis was 0.25%.

Spontaneous Post-marketing Reports:
As of February 2002, review of spontaneous post-marketing reports suggests that the rate of adverse events that potentially involve oligohidrosis is approximately 35 per 1,000,000 patients treated (including 1 reported case in Canada). Serious or clinically significant oligohidrosis or its sequelae were reported at a rate of 1.6 per 1,000,000 patients treated. As only a small proportion of suspected adverse events are usually reported, caution should be exercised in estimating the incidence of these adverse events.

Janssen-Ortho Inc. continues to work closely with Health Canada to monitor ongoing clinical trials, and worldwide pharmacovigilance reports. Janssen-Ortho Inc. will continue to provide you with the most current and complete product information available for the management of patients receiving Topamax.

The current Prescribing Information is available on the Janssen-Ortho Inc. website at Updates to the Prescribing Information will be posted on this website and will be provided for the next edition of the Compendium of Pharmaceuticals and Specialties.

The identification, characterization and management of drug-related adverse events are dependent on the active participation of Healthcare Professionals in adverse event reporting programs. Healthcare Professionals are asked to report any suspected adverse events in patients receiving Topamax (topiramate) to Janssen-Ortho Inc. at the following address:

Janssen-Ortho Inc.
Drug Safety and Surveillance
19 Green Belt Drive
Toronto, ON M3C 1L9 or
call toll free at 1-800-567-3331 or
email to

Your professional commitment in this matter has an important role in protecting the well-being of your patients by contributing to early signal detection and informed use of drugs.

Should you have any questions or require additional information regarding the use of Topamax (topiramate), please contact Janssen-Ortho Inc. Medical Information Department at 1-800-567-3331 from 9:00 a.m. to 5:00 p.m., Monday through Friday, EST.

original signed by

Wendy Arnott, Pharm.D.
Brand Integrity and Approvals

Any suspected adverse reactions can also be reported to:

Canadian Adverse Drug Reaction Monitoring Program (CADRMP)
Marketed Health Products Directorate
Health Canada
Address Locator: 0201C2
Ottawa, Ontario, K1A 1B9
Tel: (613) 957-0337 or Fax: (613) 957-0335
Toll free for consumers and health professionals:
Tel: 866 234-2345, Fax: 866 678-6789

The AR Reporting Form and the AR Guidelines can be found on the TPD web site or in The Canadian Compendium of Pharmaceuticals and Specialties.

[Text of letter ends]