NARCAN
The brand name for naloxone, a medication that rapidly reverses opioid overdose by blocking opioid receptors and restoring breathing in patients who have stopped breathing or are severely depressed.
In the Field
Naloxone, sold as Narcan, is one of the few medications a non-medical responder can administer with confidence in a life-threatening situation. It does one thing well: it reverses opioid overdose. It is safe to give if the responder is wrong about the cause, has minimal side effects in opioid-naive patients, and works fast enough to be useful before EMS arrives. Carrying it has become standard for law enforcement, school staff, and prepared citizens in many jurisdictions because the opioid crisis has put the call within reach of anyone who works around people. If you have not added naloxone to your everyday or duty kit, you are working with an outdated equipment list.
Common Mistake
Withholding naloxone administration in suspected overdose because of uncertainty about the cause, when naloxone is safe to administer in opioid-naive patients and the cost of withholding in a true overdose is death.
Technical Detail
Naloxone (Narcan, Kloxxado, Zimhi, generic) is an opioid receptor antagonist medication. It binds to opioid receptors in the body without activating them, displacing opioids that are bound to those receptors and reversing the effects of opioid intoxication.
How it works. Opioids (heroin, fentanyl, oxycodone, morphine, codeine, methadone, and others) bind to mu-opioid receptors in the brain and body, producing analgesia, euphoria, and at higher doses respiratory depression. Naloxone has higher affinity for these receptors than most opioids, so when administered it competitively displaces the opioid, reversing the receptor-mediated effects.
The clinically critical effect is reversal of respiratory depression. Opioid overdose deaths typically occur because the patient stops breathing, not from any other mechanism. Naloxone restores the respiratory drive, allowing the patient to breathe on their own.
Onset of action:
Intranasal: 2 to 5 minutes.
Intramuscular: 2 to 5 minutes.
Intravenous: less than 1 minute.
Duration of action: Approximately 30 to 90 minutes.
Forms and dosing. Naloxone is available in several forms:
Intranasal spray (Narcan brand). 4 mg per spray, single-dose disposable atomizer. The most common form for non-medical and law enforcement use.
Intranasal spray, higher dose (Kloxxado). 8 mg per spray. Used in regions with high-potency synthetic opioids (fentanyl).
Intramuscular auto-injector (Zimhi). 5 mg pre-filled syringe.
Vial for injection. Used by EMS providers for IM or IV administration. 0.4 mg or 2 mg per mL concentrations.
Specific dosing depends on form. For intranasal Narcan, a single 4 mg dose is administered, with repeat administration every 2 to 3 minutes if no response.
Field application. Naloxone administration in a suspected opioid overdose follows a straightforward protocol:
Recognize the suspected overdose. Signs include unresponsiveness, slow or absent breathing, pinpoint pupils, and (often) evidence of opioid use at the scene.
Call 911 if not already dispatched.
Administer naloxone. The intranasal form is administered by inserting the atomizer into one nostril and pressing the plunger. No medical training is required.
Provide rescue breathing if the patient is not breathing. Naloxone reverses respiratory depression but takes minutes to take effect. Rescue breathing during that window can be life-saving.
Position the patient. Recovery position if the patient resumes breathing on their own.
Monitor and re-dose. Naloxone has a shorter duration of action than many opioids, particularly long-acting opioids and high-potency synthetics. Patients who initially revive can re-sedate as the naloxone wears off. Repeat doses every 2 to 3 minutes if breathing remains depressed.
Transport to higher care. All overdose patients should be evaluated by EMS and transported, even if naloxone reverses the immediate emergency.
Safety profile. Naloxone has a remarkably favorable safety profile:
In opioid-naive patients (someone who is unconscious for a non-opioid reason). Naloxone produces essentially no effect.
In opioid-dependent patients. Naloxone reverses the opioid effect, which can produce immediate withdrawal symptoms (agitation, nausea, vomiting). The withdrawal is uncomfortable but not life-threatening. The reversal is necessary to prevent death.
Adverse reactions are rare and generally limited to the withdrawal syndrome described above.
Procurement and policy. Naloxone procurement and use is shaped by several factors:
Most U.S. states have passed laws expanding civilian access to naloxone, including standing orders allowing pharmacy purchase without a personal prescription, immunity protections for laypeople administering naloxone in good faith, and laws authorizing law enforcement to carry and administer.
Federal grants for opioid response have funded substantial naloxone distribution programs.
Schools, workplaces, public venues, and houses of worship are increasingly stocking naloxone alongside AEDs and bleeding control kits.
For agencies, departments, and organizations, naloxone procurement typically involves:
State-specific protocol review for authorization.
Training (often available free through state health departments or partner organizations).
Equipment specification (intranasal Narcan is the most common civilian and law enforcement choice).
Storage and inspection cycles. Naloxone has a shelf life of typically 18 to 24 months and requires storage at moderate temperatures.
Policy framework. Standing orders, distribution authority, post-administration documentation, and reporting requirements vary by jurisdiction.
The opioid context. The opioid crisis in the United States has shifted naloxone from a hospital pharmacy item to a standard public safety equipment item. Synthetic opioids, particularly fentanyl, have dramatically increased overdose lethality and the frequency of naloxone administration in field settings. Modern protocols often allow for higher initial doses or repeat dosing in suspected fentanyl exposure.
How it works. Opioids (heroin, fentanyl, oxycodone, morphine, codeine, methadone, and others) bind to mu-opioid receptors in the brain and body, producing analgesia, euphoria, and at higher doses respiratory depression. Naloxone has higher affinity for these receptors than most opioids, so when administered it competitively displaces the opioid, reversing the receptor-mediated effects.
The clinically critical effect is reversal of respiratory depression. Opioid overdose deaths typically occur because the patient stops breathing, not from any other mechanism. Naloxone restores the respiratory drive, allowing the patient to breathe on their own.
Onset of action:
Intranasal: 2 to 5 minutes.
Intramuscular: 2 to 5 minutes.
Intravenous: less than 1 minute.
Duration of action: Approximately 30 to 90 minutes.
Forms and dosing. Naloxone is available in several forms:
Intranasal spray (Narcan brand). 4 mg per spray, single-dose disposable atomizer. The most common form for non-medical and law enforcement use.
Intranasal spray, higher dose (Kloxxado). 8 mg per spray. Used in regions with high-potency synthetic opioids (fentanyl).
Intramuscular auto-injector (Zimhi). 5 mg pre-filled syringe.
Vial for injection. Used by EMS providers for IM or IV administration. 0.4 mg or 2 mg per mL concentrations.
Specific dosing depends on form. For intranasal Narcan, a single 4 mg dose is administered, with repeat administration every 2 to 3 minutes if no response.
Field application. Naloxone administration in a suspected opioid overdose follows a straightforward protocol:
Recognize the suspected overdose. Signs include unresponsiveness, slow or absent breathing, pinpoint pupils, and (often) evidence of opioid use at the scene.
Call 911 if not already dispatched.
Administer naloxone. The intranasal form is administered by inserting the atomizer into one nostril and pressing the plunger. No medical training is required.
Provide rescue breathing if the patient is not breathing. Naloxone reverses respiratory depression but takes minutes to take effect. Rescue breathing during that window can be life-saving.
Position the patient. Recovery position if the patient resumes breathing on their own.
Monitor and re-dose. Naloxone has a shorter duration of action than many opioids, particularly long-acting opioids and high-potency synthetics. Patients who initially revive can re-sedate as the naloxone wears off. Repeat doses every 2 to 3 minutes if breathing remains depressed.
Transport to higher care. All overdose patients should be evaluated by EMS and transported, even if naloxone reverses the immediate emergency.
Safety profile. Naloxone has a remarkably favorable safety profile:
In opioid-naive patients (someone who is unconscious for a non-opioid reason). Naloxone produces essentially no effect.
In opioid-dependent patients. Naloxone reverses the opioid effect, which can produce immediate withdrawal symptoms (agitation, nausea, vomiting). The withdrawal is uncomfortable but not life-threatening. The reversal is necessary to prevent death.
Adverse reactions are rare and generally limited to the withdrawal syndrome described above.
Procurement and policy. Naloxone procurement and use is shaped by several factors:
Most U.S. states have passed laws expanding civilian access to naloxone, including standing orders allowing pharmacy purchase without a personal prescription, immunity protections for laypeople administering naloxone in good faith, and laws authorizing law enforcement to carry and administer.
Federal grants for opioid response have funded substantial naloxone distribution programs.
Schools, workplaces, public venues, and houses of worship are increasingly stocking naloxone alongside AEDs and bleeding control kits.
For agencies, departments, and organizations, naloxone procurement typically involves:
State-specific protocol review for authorization.
Training (often available free through state health departments or partner organizations).
Equipment specification (intranasal Narcan is the most common civilian and law enforcement choice).
Storage and inspection cycles. Naloxone has a shelf life of typically 18 to 24 months and requires storage at moderate temperatures.
Policy framework. Standing orders, distribution authority, post-administration documentation, and reporting requirements vary by jurisdiction.
The opioid context. The opioid crisis in the United States has shifted naloxone from a hospital pharmacy item to a standard public safety equipment item. Synthetic opioids, particularly fentanyl, have dramatically increased overdose lethality and the frequency of naloxone administration in field settings. Modern protocols often allow for higher initial doses or repeat dosing in suspected fentanyl exposure.