I am trying to find out what this pill is:
Large, White oblong pill. One side has 500 on it, the other has a symbol like a large triangle with a smaller one inside and the number 571.
This pill is METFORMIN 500 MG SR
a generic version of Glucophage XR
Imprint Code Andrx logo and 571 / 500
Description white, oblong tablet
Info at https://www.drugs.com/metformin.html