Is your diabetes drug giving you cancer?
Let's be clear about one thing. This isn't the first red flag that's popped up for the class of drugs (TZDs) I'm going to be talking about today. Sadly, it's far from it. In fact, that's what's so frustrating about these latest findings. Had the red flags been taken seriously, a whole lot of suffering may have been avoided. And if people had been chosen over profits a whole lot of tragedy could have been avoided.
But I'm getting a little ahead of myself here. Let me back up and fill you in a bit before I share the latest bad news with you.
Thiazolidinedione (TZD) drugs that are used to treat type-2 diabetes...and the sometimes deadly side effects that can come with them...are not new. The first TZD drug to be approved by the FDA, troglitazone (Rezulin®), was fast-tracked by the organization and approved way back in July of 1996.
Within three short months concerns about troglitazone's negative effects on the liver and heart were starting to bubble up. Two medical trials conducted by the drug's manufacturer had turned up worrying data on liver injuries and heart problems among the drug's users.
But federal authorities looked the other way as the TZD drug's manufacturer racked up over $2.1 billion in sales. The FDA initially assured doctors that troglitazone's benefits outweighed any risk. Meanwhile, as the serious adverse events continued to mount the drug was withdrawn in the U.K. by November 1997.
In March of 2000 the FDA finally asked the manufacturer of Rezulin, Parke-Davis/Warner-Lambert (who later merged with Pfizer), to remove the drug from the market. By the time it was finally yanked from the US market because of its link to severe liver toxicity on March 22, 2000 there were 63 confirmed deaths linked to troglitazone.
Going from bad to worse
And if the TZD story ended with troglitazone it would be tragic enough. But it didn't. Two other drugs that fall into this potentially dangerous class of drugs as well ...the names of which you will undoubtedly recognize, Actos and Avandia... began popping their own red flags.
In September of 2010 the FDA announced restricted access to Avandia (rosiglitazone) after studies had linked it to an increased risk of cardiovascular events such as heart attacks. Then in June of 2011 the FDA warned that using Actos (pioglitazone) for more than a year may be associated with an increased risk of bladder cancer.
Amazingly, both drugs remained on the general market, despite these seemingly obvious dangers, until November of 2011 when the FDA finally announced that Avandia would no longer be available through pharmacies (but you can still get the drug if you enroll in a special program).
And that brings us to the most recent bad news about TZD drugs.
Bladder cancer risk skyrockets
I wish I could say I'm surprised by these latest findings, but considering all the red flags we've seen before now I can't. According to a new study published in the Journal of the National Cancer Institute thiazolidinedione drugs raise the risk of bladder cancer. (See, what I mean? Not really a stunner with what we already knew about Actos.)
Actos is currently the ninth most commonly prescribed drug in the United States. And TZDs account for up to 20 percent of the drugs prescribed to diabetics. If you were to do the math you'd find that, shockingly, more than 15 million Americans are now at an increased risk for bladder cancer as a result of taking them.
According to researchers from the Perelman School of Medicine, TZD users are two to three times more likely to develop bladder cancer than those who took another common class of diabetes drugs.
And since diabetics are already at a slightly increased risk for bladder cancer if you happen to have diabetes this is news that should have you picking up the phone to talk to your doctor about changing your meds if you're still on a TZD drug.