I used Actos for years, successfully, until I got an insurance notice
saying they wanted me to change.
Switched back to Avandia, which I had tried earlier. No noticeable
change in A1C level, but it gave me constipation (NOT one of the
listed possible side effects), so I soon switched again, to Januvia.
No noticeable A1C change from the second switch.
Have been using only one oral diabetes medicine at a time, with a
low-carb, high-protein diet to help.