Oxb5?

Updated

Small and disk-shaped/circular. Primarily blue in colour, with white-ish colour to it. Almost as if blue and white powders had been compressed.
One side had an indented line, possibly used to break the pill into two. The other side had three characters on the top (which I believed to be O X B, apparantly not) and one on the bottom (I thought it said 5).
I can't be sure about this, but I believe the packet had a long name begining with the letter 'h'.
Thanks for any help.