What was that liquid that Echo drank, shortly before (spoiler)

In a brief scene shortly before we learned that Echo had crashed her car and died we see her fetching a small bottle from her purse, pouring herself a small spoonful of some mysterious liquid, and then downing it. Since it was a smallish portion (no more than about a teaspoon) I'm assuming it was some sort of drug mixture, maybe something like Laudanum or some such. I wonder what it was she was taking, and why?




“Make sure you learn music the right way! I knew a guy who learned music the wrong way. He was forced to play bad polka music the rest of his life until he died one day, penniless, slumped over his accordion on the sidewalk, and people merely stepped over his lifeless body.”