Naltrexone blocks opioid receptors and works best once you are already off opioids. Suboxone eases withdrawal and cravings and can be started while opioids are still in your system. Both are proven options for opioid use disorder treatment, and the better choice depends on where you are right now.
If you are still using opioids, Suboxone is usually the starting point, because it treats withdrawal and cravings immediately. That is also why some people start with Suboxone for detox before settling on a long-term plan. If you have already been opioid-free for a week or more, naltrexone can protect against relapse with no opioid involved. Your clinician weighs your last use, pregnancy plans, liver health, and access to care.
Naltrexone is an opioid antagonist. It sits on the same receptors that heroin, fentanyl, and prescription opioids act on, and it blocks them. Take an opioid while naltrexone is active and it produces little or no effect.
Naltrexone does not relieve withdrawal. That is the practical catch. Because it displaces opioids rather than replacing them, starting it too early triggers sudden, severe withdrawal, so naltrexone therapy begins only after an opioid-free period.
Buprenorphine, the active medication in Suboxone, is a partial agonist. It activates the same receptors more weakly than a full opioid, which blunts withdrawal and cravings without producing the same high. The naloxone in the combination is there to deter injection.
Mechanism drives almost every practical difference between the two:
| Naltrexone | Suboxone (Buprenorphine/Naloxone) | |
| Drug Class | Opioid antagonist (blocker) | Partial opioid agonist |
| Treats Withdrawal? | No | Yes |
| Reduces Cravings? | Reduces opioid reward; does not treat withdrawal | Yes |
| Can You Start While Using Opioids? | No. Requires an opioid-free period first | Yes, once withdrawal is underway |
| Formulations | Daily tablet, or a monthly injection (Vivitrol) | Sublingual film or tablet |
| Physical Dependence | None | Yes, so stopping needs a plan |
| Main Cautions | Blocks opioid pain medicine; liver testing before and during treatment | Sedation risk with benzodiazepines or alcohol; precipitated withdrawal if started too soon |
Naltrexone comes as a daily pill or as an extended-release monthly injection sold as Vivitrol. The monthly shot removes the daily-pill decision, which is why adherence often improves on it. Our guide to Vivitrol compared with oral naltrexone walks through that trade-off.
Buprenorphine also comes in long-acting forms. Monthly injections such as Sublocade and Brixadi suit people who would rather not manage a daily dose, including those who started buprenorphine to get off 7-OH and other concentrated kratom products.
Delivery format matters more than people expect. A medication that fits your transportation, work schedule, and follow-up reality is the one you will still be taking in six months.
Buprenorphine is a first-line medication for opioid use disorder, and national bodies including the National Institute on Drug Abuse and SAMHSA describe it as reducing illicit opioid use, improving retention in treatment, and lowering overdose death risk.
Naltrexone is also an approved, effective medication, but the evidence sits differently. Its main documented limitation is the induction hurdle: many people never complete the opioid-free period required to start it, so fewer people get onto it in the first place.
Once someone is established on either medication, both support recovery. That induction gap is a large part of why Suboxone therapy is the more common starting point in outpatient programs. The comparison below is directional, drawn from the guidance published by SAMHSA, NIDA, and the American Society of Addiction Medicine, not from a single head-to-head trial.
| Question | Suboxone (Buprenorphine) | Oral Naltrexone | Injectable Naltrexone (Vivitrol) |
| Getting Started | Straightforward; started during withdrawal | Hardest of the three; needs a full opioid-free period | Same opioid-free requirement as oral |
| Staying in Treatment | Strongest retention in real-world programs | Weakest; daily pills are hard to sustain | Better than oral, since dosing is monthly |
| Overdose Risk While in Treatment | Reduced, per national guidance | Blocked effects while adherent | Blocked effects while the injection is active |
| After Stopping | Risk returns as tolerance falls | Risk returns once blockade fades | Risk returns once the injection wears off |
| Misuse or Diversion Concern | Real but limited; naloxone deters injection | Minimal; no opioid effect | Minimal; clinic-administered |
| Visit Pattern | Frequent early, then spaced out; telehealth possible | Daily dosing, plus follow-up visits | Monthly clinic visit for the injection |
The honest summary: buprenorphine wins on access and retention, and naltrexone is a strong option for someone who has already gotten through withdrawal and wants no opioid in the picture.
The single biggest factor is whether opioids are in your system today. Everything else, including pregnancy, liver health, chronic pain, and other substances, refines the answer rather than driving it.
| Your Situation | Usually Favored | Why | What to Do Next |
| Still using opioids | Suboxone | Treats withdrawal and cravings now; no detox required first | Ask about a same-day or next-day start |
| Opioid-free for a week or more | Naltrexone | Blocks opioid effects and removes the reward, with no opioid dependence | Confirm the opioid-free interval and get liver testing |
| Pregnant or planning pregnancy | Buprenorphine | Better documented in pregnancy than naltrexone, and untreated opioid use carries real risk | Ask about treatment during pregnancy and obstetric co-management |
| Chronic pain needing opioids | Individualized | Naltrexone blocks opioid pain relief entirely | Bring both your pain prescriber and addiction clinician into the plan |
| Liver disease or heavy alcohol use | Individualized | Naltrexone requires liver monitoring | Share your full history so labs can be reviewed first |
| Also using benzodiazepines | Individualized, often Suboxone first | Sedatives raise breathing risk with buprenorphine, so it needs supervision | Disclose everything you take, including over-the-counter drugs |
Three details change the recommendation more than anything else. Bring them to your first visit.
Both medications carry one shared risk during transitions: precipitated withdrawal, which is sudden and severe withdrawal caused by starting the wrong medication at the wrong moment. Timing is what prevents it, and timing is a clinical decision.
For buprenorphine, clinicians confirm that withdrawal is genuinely underway before the first dose, usually with a standardized measure. Our COWS assessment guide explains how that scale works and what clinicians look for.
For naltrexone, the requirement is the opposite: enough opioid-free days that no opioid remains active. The length depends on which opioid was used and in what form, and ASAM guidance sets the standard your prescriber follows.
Switching from buprenorphine to naltrexone needs a documented plan. Some clinicians use a gradual cross-taper instead of an abrupt stop. Never attempt either start or a switch on your own, and never adjust doses without your prescriber. If neither medication feels right, our guide to other options besides Suboxone walks through how switching works.
If precipitated withdrawal happens, treatment exists. Get urgent care right away if any of the following show up:
For a suspected overdose, use naloxone and call 911 immediately.
Each medication has a distinct safety profile, and neither is monitored casually.
Common effects include:
Liver enzymes can rise, so clinicians check liver function before starting and again if symptoms appear. Seek care for abdominal pain, dark urine, or yellowing skin. Details are in our overview of naltrexone side effects.
Common effects include:
The serious risk is respiratory depression when it is combined with benzodiazepines, alcohol, or other sedatives. Stopping abruptly brings withdrawal, so tapering is planned.
Tolerance drops while you are in treatment. Returning to a previous dose after stopping any medication for opioid use disorder can be fatal, and the weeks right after stopping are the most dangerous stretch.
Practical protection looks like this:
Naltrexone and naloxone get confused constantly, and they do different jobs. One blocks opioids for weeks, the other reverses an overdose in minutes. Keep naloxone on hand whichever medication you take.
Restarting treatment is always available. A return to use is a reason to call, not a reason to disappear.
Porch Light Health provides medications for addiction treatment at clinics across Colorado and New Mexico, through mobile medical units, and by telehealth. Suboxone therapy and naltrexone therapy are both part of that care.
Ready to start? Call Porch Light Health at 866-839-8868 or send us a message and we will get you connected with a clinician.
Is Suboxone better than naltrexone?
For most people who are actively using opioids, buprenorphine is the recommended starting point because it treats withdrawal and cravings immediately and keeps people in care longer. Naltrexone is a strong option for someone already opioid-free. Neither is universally better.
How long do I have to be off opioids before starting naltrexone?
Long enough that no opioid is still active at the receptor, which depends on the specific opioid and formulation. Your prescriber sets the interval based on your history and current guidance, and may confirm it before giving an injection.
Can I switch from Suboxone to naltrexone?
Yes, with a supervised plan. The transition requires an opioid-free window or a gradual cross-taper to avoid precipitated withdrawal, and it should never be attempted without a prescriber.
Does naltrexone block pain medication?
Yes. While naltrexone is active, opioid pain medicines will not work normally. Tell any surgeon or emergency clinician that you take it, and plan ahead for scheduled procedures.
Can I take Suboxone if I also take a benzodiazepine?
Sometimes, with closer monitoring. Combining buprenorphine with benzodiazepines, alcohol, or other sedatives raises the risk of dangerous sedation and slowed breathing, so your clinician needs the full list of what you take.
Which medication is safer during pregnancy?
Buprenorphine has better-documented use in pregnancy than naltrexone, and untreated opioid use carries real risk to both parent and baby. Care is co-managed with an obstetric provider and decisions are individualized.
Will Medicaid cover this?
Porch Light accepts Medicaid and Medicare, and coverage details vary by plan and eligibility. Our post on whether Medicaid covers Suboxone covers the common questions, and staff can review your specific plan.
Can I get treatment by telehealth?
Often, yes. Porch Light delivers care through in-person clinics, mobile medical units, and telehealth, and a virtual visit is frequently the fastest way to be seen. The injectable options require an in-person visit for the shot.
What if I relapse while on medication?
Call your clinic. A return to use is clinical information, not a disqualification, and treatment plans get adjusted rather than ended. Keep naloxone on hand.
Do I need counseling alongside the medication?
Medication works best paired with behavioral support, and Porch Light can arrange counseling and psychiatry alongside your prescription. The amount and type depend on what you need and want.
No single medication is right for everyone, and you do not have to decide alone. A clinician who treats opioid use disorder every day can look at your last use, your health history, and how you will realistically get to appointments, and tell you which option fits.
Call Porch Light Health at 866-839-8868 or contact us to get started. Care is available at clinics across Colorado and New Mexico, through mobile medical units, and by telehealth.
This content is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are in crisis, call or text 988, the Suicide and Crisis Lifeline.
