Three medications are approved by the FDA to treat opioid use disorder: methadone, buprenorphine, and naltrexone. Each works differently, and the best choice depends on where someone is in their recovery, their treatment history, and their daily life. A fourth drug, lofexidine, helps manage withdrawal symptoms but isn’t a long-term treatment on its own.
Methadone: Full Opioid Agonist
Methadone is the oldest and most studied medication for opioid addiction. It fully activates the same brain receptors that heroin or prescription painkillers do, but it acts slowly and steadily rather than producing a rapid high. This eliminates cravings and prevents withdrawal symptoms without the dangerous peaks and crashes of short-acting opioids. Effective maintenance doses typically fall between 60 and 120 mg per day, taken as a liquid or tablet.
The main limitation of methadone is how it’s dispensed. In the United States, you can only receive it through certified opioid treatment programs, which usually means visiting a clinic daily (at least in the early months) to take your dose under supervision. Over time, patients who remain stable earn take-home doses, but the daily clinic visits are a significant time commitment that doesn’t work for everyone.
Methadone also carries real safety concerns. It can slow breathing, especially at higher doses or when combined with alcohol, benzodiazepines, or other sedatives. It can also affect the heart’s electrical rhythm, a condition called long QT syndrome, which raises the risk of a potentially fatal irregular heartbeat. Clinics monitor for this with periodic heart tracings. Common day-to-day side effects include constipation, sweating, drowsiness, and weight gain.
Buprenorphine: Partial Opioid Agonist
Buprenorphine only partially activates opioid receptors, which means it relieves cravings and withdrawal but has a built-in ceiling effect. Past a certain dose, taking more doesn’t increase its effects much. This makes it significantly harder to overdose on compared to methadone and gives it a wider margin of safety overall.
The most common form is a sublingual tablet or film that combines buprenorphine with naloxone in a 4:1 ratio. The naloxone component is there to discourage misuse: if someone tries to inject the medication instead of dissolving it under the tongue, the naloxone triggers withdrawal. For people who struggle with daily dosing, long-acting injectable versions are available that are administered monthly by a healthcare provider through a restricted prescribing program.
Unlike methadone, buprenorphine can be prescribed from a regular doctor’s office or telehealth visit, which makes it far more accessible. You don’t need to visit a specialized clinic every morning. This flexibility is one reason buprenorphine has become the most widely prescribed medication for opioid addiction in the U.S.
There’s one important catch with starting buprenorphine. Because it’s a partial agonist, taking it while full opioids are still active in your system can actually trigger severe withdrawal, not prevent it. You generally need to wait until you’re already in moderate withdrawal, typically at least 6 hours after your last opioid use. Clinicians use a scoring tool to confirm withdrawal is advanced enough before giving the first dose.
Side effects tend to be milder than methadone’s. Headache, nausea, constipation, and insomnia are the most commonly reported. Buprenorphine produces far less respiratory depression than methadone, making accidental overdose less likely.
Naltrexone: Opioid Blocker
Naltrexone takes the opposite approach. Instead of activating opioid receptors, it blocks them entirely. If you take an opioid while on naltrexone, you won’t feel the high. This removes the reward that drives continued use.
The most effective form is a monthly injection (380 mg administered into the gluteal muscle every 4 weeks). A daily oral tablet exists, but adherence is notoriously poor because there’s nothing stopping a person from simply skipping a dose and using opioids. The monthly injection solves this by maintaining steady blockade for a full 28 days.
Naltrexone has no potential for misuse, produces no physical dependence, and carries no risk of respiratory depression. These qualities make it appealing for people who want to be completely opioid-free. The challenge is getting started. You must be fully detoxed from all opioids, typically 7 to 14 days, before the first dose. Taking naltrexone with any opioids still in your system triggers immediate, intense withdrawal. This detox requirement is a significant barrier, and it’s one reason naltrexone tends to have lower enrollment numbers in studies.
The most common side effects of the injection are nausea, injection site reactions (pain, hardness, or itching), and headache. One critical safety concern: if someone stops naltrexone and relapses, their tolerance will have dropped dramatically. A dose that was once “normal” for them can now cause a fatal overdose.
How Retention Rates Compare
Staying in treatment is one of the strongest predictors of recovery. A study tracking patients started on medication in a hospital setting found that at 12 weeks, 35% of methadone patients remained in outpatient treatment compared to 12% of buprenorphine patients. At 30 days, those numbers were 39% and 25%, respectively. These figures reflect one specific program where patients were started on medication during a hospital visit and then transitioned to outpatient care, so they don’t represent all treatment settings. In general, methadone’s structured clinic model tends to produce higher retention, while buprenorphine’s flexibility better serves people who can manage more independent treatment.
Naltrexone retention is harder to study because fewer people complete the required detox period to start it. Among those who do start, the monthly injection form shows reasonable retention, but head-to-head data with the other two medications remains limited.
Lofexidine for Withdrawal Symptoms
Approved in 2018, lofexidine (brand name Lucemyra) was the first non-opioid medication specifically approved for managing opioid withdrawal symptoms. It doesn’t treat addiction itself. Instead, it eases the sweating, muscle aches, anxiety, and racing heart that make the first days of detox so difficult.
Withdrawal symptoms are largely driven by a surge of norepinephrine, the body’s stress chemical, once opioids are removed. Lofexidine works by calming the brain region responsible for that surge, dialing down the fight-or-flight response without activating any opioid receptors. The related medication clonidine, originally a blood pressure drug, is used for the same purpose and has been a staple of withdrawal management for decades, though it lacks the specific FDA approval for this use.
Both medications can cause low blood pressure and drowsiness, so they require monitoring during the withdrawal period. Lofexidine is typically used for a short window, bridging the gap until someone is stable enough to begin maintenance treatment with methadone, buprenorphine, or naltrexone.
Naloxone for Overdose Emergencies
Naloxone isn’t a treatment for addiction, but it’s an essential part of the broader toolkit. It rapidly reverses opioid overdoses by knocking opioids off their receptors within minutes. The most widely available form is a nasal spray delivering 4 mg in a single dose. Auto-injectors and vial-and-syringe kits are also available in various concentrations.
Naloxone is now available over the counter at most pharmacies. Its effects wear off in 30 to 90 minutes, which is shorter than most opioids last, so a second dose or emergency medical care is often still needed. Many treatment programs provide naloxone kits to patients and their families as a safety measure during recovery.
Medication Is the Foundation, Not the Whole Plan
All three primary medications work best when paired with counseling, whether that’s cognitive behavioral therapy, contingency management, peer support groups, or a combination. Medication handles the biological side of addiction by stabilizing brain chemistry, while therapy addresses the behavioral patterns, triggers, and life circumstances that sustain it. Programs that combine both consistently produce better outcomes than either approach alone.
Access varies depending on where you live. Methadone requires proximity to a certified clinic. Buprenorphine can be prescribed by any licensed provider with a standard DEA registration, following recent regulatory changes that removed the previous special waiver requirement. Naltrexone can be prescribed by any provider and administered in any clinical setting. For many people, the “best” medication is simply the one they can realistically access and stay on.