Naloxone is intended to reverse opioid overdoses, therefore it is only effective for drugs classified as opioids. Opioids include prescription painkillers such as:

  • oxycodone
  • hydrocodone
  • codeine
  • morphine
  • fentanyl,
  • heroin.

Naloxone will not be effective for overdoses due to other substances. In the event of an overdose involving fentanyl, a higher dose of naloxone may be needed, due to the increased potency.