How Long Does Naloxone Stay in the System?

After a dose of naloxone, 50 percent of the drug is excreted by the system after 24 hours, and 60 to 70 percent by 72 hours, according to RxList. In adults, Naloxone has a half-life of between 30 and 80 minutes, meaning it stays active in the system for up to 2 hours and 40 minutes.

Naloxone, also known as Narcan, is a fast-acting drug that reverses opioid effects, such as respiratory depression, low blood pressure and sedation. It is often given to treat an overdose of opioids, and it can also be given to increase blood pressure in patients with septic shock, as stated by RxList.