Wednesday, March 28, 2007

Changes To Canadian Labelling Of Tamiflu

Health Canada wishes to inform Canadians that the Canadian labelling for Tamiflu has recently been updated to include new safety information resulting from adverse reaction reports of abnormal or suicidal behaviour in Japanese children or teenagers taking Tamiflu. As of February 28, 2007, there have been no Canadian reports of deaths or psychiatric adverse events such as abnormal or suicidal behaviour in children or teenagers.

Health Canada has also received preliminary information on eight new cases in Japan of self-harm in patients taking Tamiflu, and is aware that Japan has now restricted use of Tamiflu in patients 10 to 19 years old. Further information is expected from the manufacturer, Hoffman-LaRoche Limited, and appropriate measures will be taken if necessary following analysis.

Health Canada is continuing to actively monitor adverse events reported for Tamiflu and will consider the results of the recently announced Japanese review of Tamiflu's safety when available. The connection with the drug in these new cases has not been proven. High fever or other complications from influenza can affect mental state, which in turn can lead to abnormal behaviour.

Canadians taking Tamiflu should consult with their physician if they have any questions or concerns about its use.

Any serious or unexpected adverse reactions in patients receiving Tamiflu should be reported to the Canadian Adverse Drug Reaction Monitoring Program (CADRMP) of Health Canada: email:

Sunday, March 25, 2007

Risk of bone death for Fosamax users

Q. I take Fosamax for osteoporosis. I need to have a tooth extracted, but I heard that my jaw could die if I do this. Is that true?

A. (from a specialist in oral surgery) The risk of bone death (osteonecrosis) from tooth extraction in patients taking Fosamax is very low. Osteonecrosis is characterized by jaw pain, swelling, loose teeth and exposed jawbone.

In fact, if you are at risk for this condition, keeping compromised or infected teeth in place may actually be enough to cause osteonecrosis to develop even without removing the tooth.

Here's some background about the medication to help you and your dentist make a decision:

Fosamax (alendronate) is the most commonly prescribed bisphosphonate, a group of drugs which are used to maintain bone health and treat osteoporosis.

Bisphosphonates affect the ability of bone to heal from trauma, such as dental extractions. And they all remain in the bone for years. Because the intravenous forms are more potent, their effects on bone are thought to be more significant than the oral forms.

A small number of patients who were on Fosamax have developed osteonecrosis of the jaw. These have been primarily associated with dental disease or a recent dental procedure such as extraction.

But this complication has been much more frequent in patients taking the more potent intravenous medications. In one recent study of patients with osteonecrosis, less than 3 percent of the patients had been taking Fosamax, and 97 percent were on the more potent intravenous forms.

Given that there are more patients taking Fosamax than are taking the intravenous forms, it seems that the risk of osteonecrosis from tooth extractions in the patient taking Fosamax must be very low.

The lowest-risk approach would be to try to keep the tooth by having a root canal or other procedure. On the other hand, if there is infection present or if the prognosis for the tooth is not good, removal is appropriate. Talk to your dentist or an oral surgeon about the risks versus the benefits of tooth removal given your particular circumstances.

Friday, March 23, 2007

Appeals court strikes down Pfizer's patent for Norvasc

My mother takes this. Good news for my mother and bad news for Pfizer. :)

Pfizer Inc.'s patent on the hypertension drug Norvasc was invalidated by an appeals court, opening the way for generic competition. The U.S. Court of Appeals for the Federal Circuit in Washington yesterday held invalid the patent on the drug's key ingredient, amlodipine besylate, overturning a January, 2006, ruling. Pfizer said it may appeal the decision. The patent on the drug expires in September, and Mylan Laboratories Inc. has final approval from the U.S. Food and Drug Administration to market a generic version.

Norvasc is a calcium channel blocker that selectively blocks calcium ion reflux across cell membranes of cardiac and vascular smooth muscle without changing the serum calcium concentration. It decreases peripheral vascular resistance and increasing cardiac output. The generic name is amlodipine.