REMSTARBC.ca    Rural Emergency Medicine Simulation Training and Resource - British Columbia

Toxicology is a massive topic and it would be hubris to think it could be covered in one Power Point.
This page tries to provide some overview on how to approach the overdose patient.
Poison control is your best asset and never hesitate to contact them with suspected overdose.
The link to the Power Point below will hopefully provide some initial guidance.

Below are some educational and entertainingvideos on Overdose by Dr. Billy Mallon.