VANCOUVER, British Columbia — In 2016 more than 900 people in British Columbia died of drug overdoses, a record and an 80 percent increase from 2015. The culprit: fentanyl, an opioid painkiller 100 times more powerful than morphine. The smallest error in dosage can be fatal. Overprescription of opioid painkillers created demand for the powerful drugs. In the early 2000s…