My Roommate Will Not Wake Up. I Found A Prescription

My roommate will not wake up. I found a prescription for hydrocodone-acetaminophen 10-325 in her purse. She filled her prescription yesterday (10/25). She suffered from endometrial cancer two years ago, the she had a work-related injury 18 mo. ago; thus the need for pain meds. The Rx was for 120 tabs and there are now only 52 in the container. She was a nurse and was addicted to painkillers years ago, and I'm afraid her addiction has resurfaced. The question is, is it too late to call an ambulance, or should I just wait until she wakes up? She's 52 and has gained 100 lbs., more or less, since cancer struck.