What It's Used For

Opioid overdose emergency reversal
Reversal of opioid-induced respiratory depression
Post-operative opioid reversal
Community overdose prevention programs
Harm reduction interventions

Side Effects

Common Side Effects:

Precipitated withdrawal symptoms in opioid-dependent patients
Rapid heart rate
Elevated blood pressure
Sweating
Trembling
Nausea and vomiting

Note: Side effects are typically caused by rapid opioid withdrawal rather than naloxone itself. These effects are temporary and not life-threatening.

Serious Side Effects (rare):

Severe allergic reactions
Pulmonary edema (in rare cases)
Cardiovascular effects in patients with pre-existing heart disease

Additional Information

Naloxone is an opioid antagonist medication that rapidly reverses opioid overdose. It is a life-saving medication that can restore normal breathing within minutes when given to someone experiencing an opioid overdose. Naloxone is available without prescription in most states.

How Naloxone Works

Naloxone competitively binds to opioid receptors, displacing opioids and blocking their effects. It has higher affinity for these receptors than most opioids, allowing it to rapidly reverse respiratory depression, sedation, and other overdose symptoms. Effects occur within 1-3 minutes when given intranasally or intramuscularly.

Available Formulations

Narcan nasal spray: 4 mg per spray (most common community formulation)
Kloxxado nasal spray: 8 mg per spray (higher dose for high-potency opioids)
Injectable: Various concentrations for IV, IM, or subcutaneous use
Auto-injector (Evzio): 0.4 mg or 2 mg for intramuscular/subcutaneous use

Medical Uses

Naloxone is used for:

Emergency treatment of known or suspected opioid overdose
Reversal of opioid effects in emergency settings
Post-operative reversal of opioid-induced respiratory depression
Prevention of overdose death in community settings

Administration in Emergency

For suspected overdose, call 911 immediately. For nasal spray: spray into one nostril while patient is lying on their back. For injection: inject into outer thigh (can inject through clothing). If no response in 2-3 minutes, give additional doses. Continue monitoring and rescue breathing until help arrives.

Duration and Repeat Dosing

Naloxone has a shorter duration of action (30-90 minutes) than most opioids. Overdose symptoms may return as naloxone wears off, especially with long-acting opioids like methadone or extended-release formulations. Multiple doses and continued monitoring are often necessary.

Precipitated Withdrawal

In opioid-dependent individuals, naloxone can precipitate acute withdrawal symptoms including agitation, body aches, nausea, vomiting, diarrhea, and rapid heart rate. While uncomfortable, precipitated withdrawal is not life-threatening and is preferable to death from overdose.

Community Distribution

Many states have standing orders allowing pharmacies to dispense naloxone without prescription. Harm reduction organizations, health departments, and community programs distribute naloxone to people who use drugs and their contacts. Anyone at risk of witnessing an overdose should have naloxone available.

Storage and Stability

Naloxone should be stored at room temperature away from light. Check expiration dates regularly and replace when expired. Nasal spray should not be primed or tested before use. The medication may be less effective after expiration but should still be used if it's the only option available.

Learn more at MedlinePlus

Menu

Naloxone