Tuesday, January 15, 2008

These studies light up my lines

First estrogen in the post-WHI days. Then Avandia after studies linked this diabetic drug to an increased risk of heart disease in a population already at enormous risk of same. Now Zetia hits the headlines, and patients hit speed-dial to Capitol Hill Internal Medicine.

For those of you not yet chasing your cholesterol numbers, Zetia is a cholesterol-lowering medication that works in an entirely different manner than the statins such as Zocor (simvastatin) or Lipitor. For that reason, persons unable to tolerate statins or those whose cholesterol levels do not fall sufficiently with statins can be switched to Zetia alone for a 15% drop in their LDL levels or to Vytorin which teams Zetia with Zocor for an even larger reduction in LDL than Zocor alone.

When we monitor cholesterol levels to gauge the success of treatment, we are actually looking at 'surrogate markers.' We don't have any practical way of monitoring the actual health of your inner arterial wall, so we know, based on mountains of data from years of studies, that LDL-cholesterol levels tend to correlate with the amount of gunk in your arteries and the risk that they will ultimately block off under a heap of goo and clot.

Well, we used to know that. New data* from the ENHANCE trial suggests that, when it comes to Zetia, lower LDL levels do not necessarily translate into lower risk. This study followed 720 patients over 2 years (note small trial size and short trial duration), comparing IMT (intima media thickness of the carotid arteries which uses ultrasound technology to indirectly measure wall thickening in neck arteries**) in subjects on Zetia and Zocor vs. those on Zocor alone.

The results showed not a whit of difference between the combination of the Z drugs (aka Vytorin) and Zocor alone. Vytorin and Zetia are brand name only drugs, thus more expensive and far more lucrative to the manufacturers, while Zocor is available generically. Dr. Steve Nissen, an outspoken cardiologist from the Cleveland Clinic, is emphatically urging docs to abandon Zetia. Industry-backed investigators are hedging.

Hmm, what to say to those callers?
*Actually, it is oldish data that has only been newly released, and perhaps only released under pressure from a congressional committee.
**IMT is also a surrogate marker,


Dr. Smak said...

This is more evidence that one of the more educated segments of the population (doctors) are under significant influence from the pharmaceutical industry, whether we want to believe so or not. There has never been any disease or outcome oriented evidence that Zetia is beneficial. It should never have served a role except in the cases you suggested, either statin intolerance or as an add-on if LDL goal was not reached. I've seen many a patient who was taking Zetia exclusively.

But what to do now, with the diabetic on 80 mg of simvastatin with an LDL of 125?

There remain no clear answers.

But the last people we should be talking to is the drug reps.

Cilicious said...

I appreciate a doc telling the truth, even if it's just "I don't know for sure."
I've been reading about Zetia users having elevated liver enzymes and even liver damage.
Drugs and drug companies are supposed to help us--but of course they are in this risky business for profit, and the situation can be murky at best, tragic at worst.
We had a horrible time with our dog and Deramaxx, the canine version of Celebrex.