Sublocade & Brixadi: Long-Acting Buprenorphine Injections

Long-acting buprenorphine injections — when they help, the long discontinuation tail, who they fit.

⚠️ Information channel, not medical advice. This is reference material on extended-release buprenorphine injections. For discussion, questions, or community support, see #suboxone or post in general support channels. For long-term maintenance discussion specifically, r/suboxone is the better resource.

Sublocade and Brixadi are two FDA-approved long-acting buprenorphine injections used in medication-assisted treatment (MAT) for opioid use disorder. Both contain buprenorphine, the same active ingredient as Suboxone, just delivered as a slow-release subcutaneous depot rather than as a daily sublingual film or tablet.

This post exists because some people in this community have been offered these injections by their prescribers, and the pharmacology, dosing, and discontinuation profile differ enough from oral Suboxone that it’s worth understanding before agreeing to one.

Heads up about this site’s focus: these are maintenance-oriented medications. They’re designed for stable, sustained dosing over months to years, not for short tapers. This site is focused on short-term tapers, so for most people here, daily sublingual Suboxone with a structured taper plan will be a better fit than long-acting injections. That said, the information below is here so you can have an informed conversation with your prescriber if these come up.

What they are

Sublocade (approved 2017) is a monthly subcutaneous injection. The liquid forms a solid depot under the skin that releases buprenorphine over ~28 to 30 days. Doses: 100 mg or 300 mg.

Brixadi (approved May 2023) is a subcutaneous injection that comes in both weekly and monthly formulations, providing more dosing flexibility than Sublocade. Weekly doses: 8, 16, 24, or 32 mg. Monthly doses: 64, 96, or 128 mg.

Key differences

Dosing flexibility: Brixadi offers weekly or monthly options; Sublocade is monthly only.
Injection sites: Sublocade is injected in the abdomen only. Brixadi can be injected in the buttock, thigh, abdomen, or upper arm.
Initiation requirements: Sublocade requires at least one dose of transmucosal buprenorphine and a 1-hour observation period before injection. Brixadi can be initiated with a single test dose of transmucosal buprenorphine, and weekly Brixadi can be used to start treatment in people new to buprenorphine.
Dose strength: Sublocade only comes in higher doses; Brixadi has lower-dose weekly options that some people find easier to start with.

How they work

The depot under the skin releases buprenorphine into the bloodstream at a controlled rate. Once steady-state is reached (typically after a few injections), plasma buprenorphine levels stay relatively constant between doses, which avoids the daily peak-and-trough cycle of oral Suboxone. For people whose adherence is a problem with daily dosing, this is a significant practical advantage. For people who are stable on oral and want fine-grained dose control, it removes that flexibility.

The very long half-life (this is the part that matters most)

The terminal half-life of Sublocade is 43 to 60 days. Brixadi monthly is similar; Brixadi weekly is shorter. For comparison, oral buprenorphine has a half-life of ~24 to 42 hours.

Practical consequences:

After a single Sublocade injection, buprenorphine remains detectable in the body for approximately 172 to 300 days (5 to 10 months).
After multiple injections, total elimination can take a year or more.
Withdrawal symptoms after stopping may not appear for several weeks after the last injection, then ramp up gradually as plasma levels finally drop.
Withdrawal symptoms may peak around 1 to 2 months after the last injection, not days like oral bupe.

This is the single most important thing to understand before agreeing to one of these injections. You are committing to a medication that will be in your body for many months after your last dose, whether you want it there or not. Once it’s injected, it can’t be removed (Sublocade can only be surgically removed within 14 days of injection, and only under specific clinical circumstances).

For some people, this is a feature: it removes daily decision-making, prevents missed doses, and provides a built-in slow taper if they decide to stop. For others, it’s a bug: it locks them into the medication and into clinic visits, and makes any change of plan slow.

Discontinuation profile

Because of the long half-life, stopping these injections is essentially a built-in slow taper. Plasma buprenorphine declines gradually over months. Some clinicians and patients view this favorably; some view it as a multi-month withdrawal tail rather than a clean exit.

Reddit-based qualitative research on stopping Sublocade found patients reported a wide range of experiences. Some had relatively mild withdrawal due to the gradual decline; others reported a long, drawn-out process with extended PAWS-like symptoms because plasma levels never drop sharply enough to trigger a clean withdrawal-then-recovery curve.

Brixadi’s prescribing information notes that if discontinued, ongoing buprenorphine effects should be monitored for ~1 month for weekly and ~4 months for monthly formulations.

When these might make sense

Adherence problems with daily oral dosing. Missing oral Suboxone doses can lead to relapse; injections eliminate that risk.
Stable maintenance over months to years is the actual goal (rather than a short taper).
High-stakes life situations (incarceration transitions, custody arrangements, employment requirements) where consistent treatment is critical.
Diversion or theft concerns in a household.
Cravings that aren’t controlled by oral bupe even at maximum dosing.

When these might not make sense

Short taper is the goal. These medications make a fast, controlled exit much harder. Once injected, the long tail is unavoidable.
You’re still figuring out the right dose. Dose changes are slow, monthly affairs rather than day-to-day adjustments.
You’re considering pregnancy. Talk to your prescriber. Buprenorphine is generally considered acceptable in pregnancy, but the long-acting nature complicates things if changes are needed.
You haven’t been stable on oral bupe for at least a week. Sublocade specifically requires this.
Cost or access issues. Brixadi requires REMS-certified providers and pharmacies.

What to ask if your prescriber suggests one

What’s the long-term plan? Indefinite maintenance, or a defined endpoint?
If I want to stop, what does that look like, and how long will I feel effects after the last injection?
Why this over continuing oral bupe, in my specific situation?
For Brixadi: weekly or monthly, and why?
What happens if I miss an appointment or move away from this clinic?
Is the cost covered by my insurance, and what’s my out-of-pocket?
Can I switch back to oral bupe later if needed?

Cost and access notes

Both medications are expensive without insurance coverage. Sublocade list price is around $1,500 to $1,900 per monthly injection. Brixadi pricing varies by dose. Most insurance plans cover one or both as part of MAT, but prior authorization is common. Manufacturer assistance programs exist for patients who qualify.

Both medications must be administered by a healthcare provider; you can’t take them home.

Sources

🩺 Reminder: This is informational content. Long-acting buprenorphine decisions should be made with a prescriber familiar with your specific situation, especially given the multi-month commitment these injections involve. The community here is mostly oriented toward shorter-term tapers, so if you’re considering long-term maintenance, additional resources like r/suboxone may be more useful.