The best replacement for naloxone is naltrexone.

The best alternatives to naloxone are rated as following:
★★★★★  naltrexone
★  narcan
★  buprenorphine
★  methadone

Your alternative for naloxone is not listed? Suggest!
Speaking about naloxone, one probably shouldn't forget about buprenorphine.

Other search terms related to naloxone and their ratings are:

★★★★★ buprenorphine
You have in mind a companion for naloxone and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of naloxone in all years. Click on graph for more.