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Consumer Reports Insights: Doubts surface about the safety of a diabetes drug

Tuesday, June 29, 2010; HE02

If you need a drug for Type 2 diabetes, Consumer Reports has long advised that a time-tested older medication called metformin is your safest and best first bet. Two studies published Monday, both involving a newer drug, Avandia, underscore why.

In the first study, published in the Journal of the American Medical Association, researchers led by David Graham of the Food and Drug Administration analyzed Medicare records of more than 227,000 people who took either Avandia or another diabetes drug, Actos. They found that those using Avandia had an increased risk of stroke, heart failure and death.

In the second study, published in the Archives of Internal Medicine, Steven Nissen of the Cleveland Clinic updated his 2007 meta-analysis (an analysis that includes results of several studies) of Avandia. The new analysis, which included 14 additional studies on top of the 42 that made up the original meta-analysis, confirmed his previous finding that Avandia increases the risk of heart attacks.

An FDA advisory committee is set to discuss the safety of Avandia in mid-July. The drug already carries a warning that it can cause heart failure, but some FDA officials think it also causes heart attacks and should be pulled from the market. According to internal reports released by leaders of the Senate Finance Committee earlier this year, FDA officials speculate that if patients on Avandia were switched to Actos, 500 heart attacks and 300 cases of heart failure could be prevented every month.

The FDA documents were discovered in a two-year investigation into Avandia by the committee; its report charged that the manufacturer, GlaxoSmithKline, knew of the heart risks associated with the drug for years before the danger was made known to the public. Avandia now carries a black-box warning -- the FDA's strongest -- that the drug can cause or worsen heart failure.

GlaxoSmithKline issued a statement denying the allegations.

The report also raised grave concerns about the FDA's handling of a study that is comparing the heart risks of Avandia with Actos or a placebo. In the internal reports, FDA officials called the trial unethical and unsafe for patients, given the known heart risks of Avandia. If you are involved in this study, called the TIDE trial, ask your doctor whether Avandia or Actos is appropriate for you. (Actos also carries a warning that it can cause heart failure.)

For people who need a diabetes drug, Consumer Reports' free Best Buy Drugs report recommends metformin, either alone or with glipizide or glimepiride, as the first option. It has a well-established safety profile and is available as an inexpensive generic.

Type 2 diabetes drugs improve the body's processing of sugar. When they work well, a test measuring the long-term presence of blood sugar called HbA1c improves. Studies show that the newest medicines are not any more effective than those that have been around for decades, such as the sulfonylureas and metformin. In fact, three of the newer medicines -- acarbose, miglitol and nateglinide -- actually decrease HbA1c less than some of the older drugs. Also, all diabetes drugs have the potential to cause adverse effects, both minor and serious. The newer drugs don't have a safety advantage; in fact, they may be less safe.

Start with metformin, which offers the best combination of effectiveness, safety and affordability. Studies show that people who have trouble controlling their HbA1c level using a single medication do better if they add a second drug. Taking two medicines at once does raise the risk of side effects. But if you run into problems, your doctor may simply recommend that you try lowering the dose of one or both drugs.

Taking into consideration their overall effectiveness, safety, side effects, dosing and cost, Consumer Reports chose the following diabetes medicines as Best Buys. All of them are available as low-cost generics, costing from $10 to $60 a month, sometimes less:

-- Metformin, alone or in combination with glipizide or glimepiride.

-- Glipizide and glipizide sustained release, alone or in combination with metformin.

-- Glimepiride, alone or in combination with metformin.

Copyright 2010. Consumers Union of United States Inc.

For further guidance, go to ConsumerReportsHealth.org. More-detailed information -- including CR's ratings of prescription drugs, conditions, treatments, doctors, hospitals and healthy-living products -- is available to subscribers to that site.

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