Fluoroquinolone antibiotics: patients with myasthenia gravis may risk increased muscle weakness

Starting date:

November 7, 2011

Posting date:

November 7, 2011

Type of communication:

Information Update

Subcategory:

Drugs

Source of recall:

Health Canada

Issue:

Important Safety Information

Audience:

General Public

Identification number:

RA-110004668

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  Media enquiries
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Patients with a rare condition known as myasthenia gravis who take a fluoroquinolone antibiotic may risk a worsening of their symptoms, including muscle weakness or breathing problems. The risk of this happening is considered rare, but serious. Use of fluoroquinolone antibiotics should be avoided in patients with a known history of myasthenia gravis.

Myasthenia gravis is a rare, chronic (long-lasting and recurring) disease that causes progressive muscle weakness. Muscles affected by this condition include eye and face muscles, neck and throat muscles, and limb muscles. Activity makes the muscle weakness worse, and symptoms generally improve with rest.

Fluoroquinolone antibiotics are a class of prescription drugs used to treat certain types of bacterial infections in adults, such as respiratory tract infections, skin infections and urinary tract infections. (See below for a list of fluoroquinolone drugs in Canada).

Health Canada has notified the Canadian manufacturers of fluoroquinolone antibiotics to update the labelling to include a warning on this risk.

There are alternative antibiotics available in Canada. Patients with myasthenia gravis should:

• Tell your healthcare practitioner about all of your medical conditions, including myasthenia gravis.
• Talk to your healthcare practitioner if you have questions or concerns about your antibiotic treatment.
• Seek medical treatment if you notice a worsening of muscle weakness or breathing problems.

How to report side effects to health products

To report suspected adverse reaction to these or other health products, please contact Health Canada's Canada Vigilance Program toll-free at 1-866-234-2345, or complete a Adverse Reaction Reporting Form and send to us using one of these methods:

• Fax: 1-866-678-6789
• Internet: MedEffect Canada
• Mail: (Canada Vigilance Postage Paid Label)
  
  Marketed Health Products Directorate
  
  Ottawa, ON, Address Locator 0701E
  
  K1A 0K9

Fluoroquinolone drugs currently marketed in Canada

Fluoroquinolone antibiotics are available in multiple formulations. The risk to myasthenia gravis patients appears to apply to formulations taken by mouth (liquids and tablets/extended release tablets) or that are injected intravenously (into a vein). Based on available data, the risk does not appear to apply to ear or eye drops.

Below is a list of brand names of fluoroquinolone antibiotics, their generic equivalent and the active ingredient. There are many fluoroquinolone antibiotics currently sold in Canada; for simplicity, the table provides the drug names, but not the variations in strengths, formulations or routes of administration.

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