Overdoses happen because people are doing hard drugs while alone and/or are getting bad drugs. Prevention of overdosed means not locking up addicts for basic possession. Safe injection sites. Basic communication services such as handing out cellphones to addicts can make a huge difference (the cost of one ER visit will buy 100 cellphones). These things can be done now.

Stopping people from becoming addicts is different. It requires societal change so that people don't land in situations where they are likely to turn to drugs. That means employment programs. That means post-hospital monitoring of patients. That means decent affordable housing. That means much more expensive and long-term efforts.