Other safety alerts
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| Canada: Azithromycin (Zithromax® /Zmax SR®) - Risk of Potentially Fatal Cardiac Arrhythmias |
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Pfizer Canada Inc., in collaboration with Health Canada, informed healthcare professionals and the public with respect to the revised Product Monographs for Zithromax and Zmax SR (azithromycin) regarding the risk of potentially fatal cardiac arrhythmias. A small absolute increase in the risk of cardiovascular deaths was observed in patients taking azithromycin as compared to those who took no antibiotics and those who took amoxicillin in a recent study. This risk mainly affected patients who were at a higher baseline risk for cardiovascular events.
Pfizer completed a review of all relevant available data, and updated the Precautions section of the Zithromax and Zmax SR product monographs to include the following additional instructions:
There have been rare reports of QT prolongation and torsades de pointes in patients receiving therapeutic doses of azithromycin.
Caution is required when treating patients with congenital or documented QT prolongation; with electrolyte disturbance, particularly in cases of hypokalaemia and hypomagnesemia or with clinically relevant bradycardia, cardiac arrhythmia or cardiac insufficiency.
Caution is also required when treating patients currently receiving treatment with other active substances known to prolong QT interval such as antiarrhythmics of classes IA and III, antipsychotic agents, antidepressants and fluoroquinolones.
Elderly patients may be more susceptible to drug-associated effects on the QT interval.
Prolonged cardiac repolarization and QT interval have been seen in treatment with macrolides including azithromycin. Healthcare practitioners should consider the risk of fatal cardiac arrhythmias with azithromycin when prescribing antibacterial treatment for patients who are already at risk for cardiovascular events.
It is advised that patients who are currently prescribed Zithromax or Zmax SR should talk to their doctors or healthcare providers if they have questions regarding their treatment. Before taking Zithromax or Zmax SR, patients are advised to talk to their doctor or pharmacist if the following conditions apply: known prolonged heart cycle (interval) (QT prolongation); currently taking medication known to prolong QT interval (prolong the heart cycle) such as antiarrhythmics (drugs to regulate the heart beat such as class IA: quinidine, procainamide and class III; dofetilide, amiodarone, sotalol); antipsychotic agents; antidepressants; and fluoroquinolones (a class of antibiotics); constantly low levels of potassium or magnesium; or history for heart problems such as bradycardia (slow heart rate), cardiac arrhythmia (irregular heart beat) or cardiac insufficiency (the heart has a hard time pumping blood to your body).
Please refer to the following website in Health Canada for details:
http://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/../29199a-eng.php
In Hong Kong, there are 62 registered pharmaceutical products containing azithromycin and are prescription-only medicines. Related news has been released by FDA and HSA, and was posted on the website of Drug Office on 18 May 2012, 13 March 2013 and 6 May 2013. Letter to inform healthcare professionals to draw their attention on the issue and urge them to report any adverse drug reaction related to the drug was issued on 18 May 2012. In view of the updated recommendations released by Health Canada, a letter to inform healthcare professionals will be issued. So far, the Department of Health has not received any related adverse reports in connection with the drug. As reported on 13 March 2013 and 6 May 2013, the matter will be discussed in the meeting of the Registration Committee of the Pharmacy and Poisons Board. The Department of Health will keep vigilant on any updated news of this product.
Ends/ Saturday, May 18, 2013
Issued at HKT 12:30
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