A B.C. man is going public to warn others after his mother was killed by an adverse interaction between two prescription drugs, a well-known risk that was overlooked by health professionals she trusted."There was a physician and two pharmacists and a computer system that all failed here. It’s not a simple mistake,” said Ernie Lambert, whose mother died in 2012.Helena Lambert's local pharmacists dispensed the medications without noting or warning of the potential problems of taking them concurrently, even though widely used software at the pharmacy would have flagged the potential adverse interaction. "The procedures weren’t followed. What [electronic] warnings there were, were ignored," Ernie Lambert said.