The calls/emails have already started to come in, and I expect more, as I have a lot of diabetes patients and have been an avid user of the TZD class. There are many reasons to like the TZD's:
1. The older, generic medicines like metformin and sulfonylureas are known to fail over time. After 3 years, most patients on one of these drugs lose control of their blood sugar. In contrast, patients on TZD's maintain glycemic control (at least up to 4-5 years which was shown in the ADOPT study).
2. The TZD's don't cause hypoglycemia, which is a really bad side effect of insulin and the sulfonylureas.
3. Many diabetic patients need more than one drug, so even if you start with metformin, you are going to have to choose between a TZD (well studied, no hypoglycemia), a sulfonylurea (well studied, causes hypoglycemia), or a DDP4 inbitor like Januvia/Ongyza (not as well studied, no hypoglycemia).
4. TZD's have other benefits that the other diabetes drugs don't, such as improving good cholesterol or HDL, and decreasing triglycerides or fats. In his presentation the Periscope study, which showed Actos prevented plaque build up, Dr. Nissen (wonder why he likes Actos?) compared these results to other similar cholesterol lowering studies and showed an ldl-independent effect of the TZD's in their ability to prevent plaque build up. He believed this was due primarily to increases in HDL.
5. Using a TZD, likely because of sustained glycemic control, prevents the need for insulin. This was shown in the recently maligned RECORD study and the NIH sponsored BARI-2D study. Insulin causes hypoglycemia and most of my patients would like to avoid insulin.
The first patient contacted me by email related what he had heard about the FDA panels finding. He understood that they recommended not to pull the drug, but also felt that there were enough concerns that he wanted to switch. He was on Avandia 4mg, so I switched him to Actos 45mg.
It is important to note that the TZD's have their maximal effect at the maximum dose. Though the maximum dose causes the most side effects, I have found that if used early in the course of disease, side effects are minimal. The most common side effect of the TZD's is edema, or fluid retention. Use of a low dose fluid pill (which many diabetics use anyway in order to keep their blood pressure controlled) seems to eliminate this problem. For metformin, the best dose is 2000mg a day (usually 1000mg twice a day).
This brings me to the second patient who called me with similar concerns. He had been taking Avandamet 4/1000mg twice a day for about 7 - 8 years with outstanding diabetes control. In discussing the switch to Actos, we uncovered a problem. The equivalent dose of Actos is 45mg. Like Avandia, Actos comes in combination with metformin, called Actoplusmet. Actoplusmet comes in 15/500mg and 15/850 and is to be taken twice a day. If you do the math, it is very hard to get the 45/2000mg a day that would be equivalent to the Avandamet dose that has kept this patient under control for so long. We could do two pills in the morning and one a night (a more complicated regimen), but would be over (more side effects) or under (less efficacy) on the metformin dose between the 850 and 500 versions. Actoplusmet was just approved as an extended release product. This can be taken once a day (easier regimen). Actoplusmet XR comes in 15/1000 and 30/1000. If we went this route we could have the patient take one of each. The problem is that his insurance company will consider this two different medications and charge him two separate co-pays. He could take the 30/1000 and use one and a half tablets a day (wouldn't cost him more), but we would be short on the metformin, and it is generally not a good idea to split extended release pills. After spending 10 minutes discussing the above dilemma, he decided that it was simply too complicated to switch and he would stick with the Avandamet, unless the FDA decided to pull it.
Actos and Avandia are both good medications. Many of the FDA panelists who voted to pull Avandia or severely restrict it, mentioned that they did so because Actos was available and they saw no clear avantage of Avandia over Actos. No one mentioned the dosing. This is likely because few on the panel actually treat patients with diabetes. The only panelist really pushing for options was the patient advocate.
In addition, there is really no compelling evidence to believe that Actos is any safer than Avandia. The AHRQ (government, non-pharma) commissioned a study to look at this, and they found no difference. A Science Advisory From the American Heart Association and American College of Cardiology Foundation also looked at this issue (most of the authors had no ties to either product) and similarly found no substantial difference between Actos and Avandia with regards to safety. This is also why the panel voted 19-10 to move forward with the TIDE study.
Though, I am sure I will continue to get emails and phone calls from worried patients, many of the patients I have on Avandia take Avandamet 4/1000mg twice a day. Hopefully, they will read my blog before calling as multiple 10 minute phone calls start to add up.