With the growing and widespread opioid overdoses occurring on a national scale, and the resulting loss of life, the Government of Canada enacted the Good Samaritan Drug Overdose Act in 2017. The Act is actually not truly an Act, but an amendment to chapter 4 of the Controlled Drugs and Substances Act, and serves to exempt people who call 911 for drug overdoses from facing charges themselves. The reason why this was put in place was to alleviate the fear of those who could summon help but decide not to due to fear of prosecution themselves. The Act is designed to apply to anyone who seeks help, including the person who overdosed themselves.
Such legal protection granted by the Act include paroles, pre-trial releases, probation orders, simple possession, and conditional sentences. However this law is not 100%, and will not provide legal protection against outstanding warrants, production and trafficking of controlled substances, and other crimes not specified within the Act. If at all possible, stay with the person until help arrives, but the Act will cover you if you leave before help arrives.