Naloxone vs Naltrexone: Side-by-Side Comparison
Quick answer: Naloxone and Naltrexone are both opioid antagonist used for similar indications. They share a mechanism of action but differ in dosing, half-life, side-effect profile, and clinical preferences. Switching between them is a clinical decision.
Side-by-side comparison
| Feature | Naloxone | Naltrexone |
|---|---|---|
| Drug class | Opioid antagonist | Opioid antagonist |
| ATC code | V03AB15 | N07BB04 |
| Primary indications | Opioid overdose reversal, Opioid-induced respiratory depression | Alcohol use disorder, Opioid use disorder |
| Mechanism | Competitive mu-opioid receptor antagonist that displaces opioids and reverses their effects | Long-acting competitive opioid receptor antagonist blocking opioid effects and reducing alcohol craving |
| Common dose | 0.4-2 mg IV/IM/SC, repeat every 2-3 min; 4 mg intranasal | 50 mg orally once daily; 380 mg IM monthly (extended-release) |
| Detail page | Naloxone details → | Naltrexone details → |
How to choose between Naloxone and Naltrexone
Both medicines belong to the same therapeutic class and address overlapping indications. Selection between them depends on:
- Patient-specific factors: age, kidney and liver function, other medications, allergies, comorbidities
- Specific clinical indication: some class members are preferred for particular conditions or guideline recommendations
- Dosing preference: once-daily vs twice-daily, oral vs injectable, food requirements
- Tolerability: individual side-effect profiles vary even within a class
- Drug interactions: patient's other medications may interact differently with each option
- Cost and availability: generic availability, insurance coverage, regional access
Should you switch?
Switching between class members is a clinical decision, not a self-help one. Reasons your prescriber may consider switching include:
- Inadequate response to current medication
- Side effects affecting quality of life
- New drug interactions due to a recently added medication
- Cost or availability changes
- Updated guidelines favoring a different option
Never switch medications, change dose, or stop without consulting your prescriber.
Related
All Opioid antagonist on iMedic · Naloxone full details · Naltrexone full details
Frequently asked questions
Is Naloxone better than Naltrexone?
Neither is universally 'better.' They are both opioid antagonist with similar mechanisms of action. The right choice depends on the specific clinical situation, patient factors, dosing preferences, drug interactions, and tolerability. Discuss with your prescriber.
Can I switch from Naloxone to Naltrexone?
Switching is possible but should be done under clinical supervision. Different class members may not be interchangeable on a 1:1 dose basis, and tapering or transition strategies vary. Never switch on your own.
Do Naloxone and Naltrexone have the same side effects?
They share class-wide side-effect tendencies but differ in individual profiles. Some patients tolerate one better than the other. Specific frequency and severity of side effects can be found on each medicine's individual page.
Are Naloxone and Naltrexone available as generics?
Generic availability depends on patent status in your country. Most well-established class members are available generically and are clinically equivalent to brand-name versions.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.