If you use opioids while on Sublocade, you will feel little to no effect from them. Sublocade delivers a steady stream of buprenorphine that occupies roughly 70% or more of the opioid receptors in your brain, leaving very few open for other opioids to attach to. The result is a powerful blocking effect: heroin, fentanyl, or prescription painkillers can’t produce the usual high because they simply can’t reach enough receptors to do so. Trying to push past that blockade by using more is where the real danger begins.
How the Blocking Effect Works
Buprenorphine, the active ingredient in Sublocade, is a partial opioid agonist with an unusually strong grip on opioid receptors. It binds more tightly than most full opioids, meaning it can actually displace drugs like fentanyl from the receptor and take their place. Once buprenorphine is sitting on those receptors, other opioids are essentially locked out.
The Sublocade injection was specifically designed to keep blood levels of buprenorphine above the threshold needed for this blocking effect. At the standard maintenance dose (two initial 300 mg injections followed by monthly 100 mg injections), average blood levels stay around 3.2 ng/mL at steady state. That concentration keeps at least 70% of opioid receptors occupied around the clock, with no gaps or dips the way sublingual strips can have if a dose is missed or delayed. The higher 300 mg maintenance dose pushes average levels to about 6.5 ng/mL, occupying even more receptors.
This is why most people who try using on Sublocade describe it as a waste. The opioid enters the bloodstream but has nowhere to land. You might feel slight sedation from very high doses, but the euphoria that drives compulsive use is largely absent.
Why Using More to Override It Is Dangerous
The biggest risk comes from trying to break through the blockade by taking larger and larger amounts of opioids. Because buprenorphine has a ceiling effect on respiratory depression (your breathing doesn’t slow as dangerously as it does with full opioids alone), the buprenorphine itself offers some protection. But that protection has limits.
If you flood your system with enough fentanyl or heroin to compete with buprenorphine for receptor space, you can eventually overwhelm the blockade. At that point, you’ve taken a dose far beyond what your body would normally tolerate, and the risk of fatal respiratory depression spikes. Research on overdose during buprenorphine treatment confirms that overdoses do still occur, particularly in the era of illicitly manufactured fentanyl, which is unpredictably potent. The danger isn’t that Sublocade makes overdose more likely on a given day. It’s that people compensate by using far more than usual, which can turn deadly if the blockade is even partially overcome.
Combining Sublocade With Alcohol or Sedatives
Using opioids isn’t the only concern. Mixing Sublocade with alcohol, benzodiazepines (like Xanax, Klonopin, or Valium), or other sedatives carries serious risks because these substances suppress breathing through different pathways in the brain. Buprenorphine slows respiratory function through opioid receptors, alcohol works through a separate receptor system, and benzodiazepines work through yet another. When combined, their effects on breathing don’t just add up. They can multiply, making the combined impact far worse than any one substance alone.
Alcohol is involved in roughly 1 in 5 overdose deaths linked to prescription opioids and benzodiazepines each year. Because Sublocade keeps buprenorphine active in your body 24 hours a day for weeks, there is no safe window to drink heavily or take unprescribed sedatives.
What Happens With Stimulants or Other Drugs
Some people turn to stimulants like methamphetamine or cocaine while on Sublocade, either because opioids no longer work or to counteract what they perceive as the dulling effects of buprenorphine. Sublocade does not block the effects of stimulants since those drugs act on completely different brain systems (primarily dopamine and norepinephrine rather than opioid receptors). Using stimulants while on Sublocade introduces cardiovascular risks, sleep disruption, and the potential for developing a new pattern of substance use, but there is no pharmacological interaction in the way there is with opioids.
How Well Sublocade Reduces Opioid Use
Clinical trials give a realistic picture of what to expect. In the pivotal phase 3 trial, about 28 to 29% of people on either Sublocade dose achieved what researchers defined as treatment success: 80% or more of their urine samples testing negative for illicit opioids from week 5 through week 24. Only about 12 to 13% had completely clean results with no positive samples or missed tests over that same period, compared to just 1% on placebo.
These numbers tell an honest story. Sublocade dramatically reduces opioid use compared to no medication, but it doesn’t eliminate it for everyone. Some people do use, especially early in treatment. The blocking effect makes each use less reinforcing, which over time helps weaken the cycle. The steady blood levels, with no daily dosing decisions, remove one of the common failure points of other buprenorphine formulations.
What This Means for Pain Management
One practical consequence of Sublocade’s receptor blockade is that managing acute pain becomes more complicated. If you’re in an accident, need surgery, or develop severe pain, standard opioid painkillers will be less effective because your receptors are already occupied by buprenorphine.
Current clinical guidance recommends keeping buprenorphine in place rather than stopping it, even during surgery. Pain is managed through a combination of non-opioid approaches: anti-inflammatory medications, nerve blocks, acetaminophen, and other pain-modulating drugs. For moderate to severe pain, short-acting opioids can still be added on top of buprenorphine, but higher doses than usual are needed because they’re competing for receptor space. If you’re on Sublocade and face a planned procedure or emergency, make sure your medical team knows about the injection so they can plan accordingly.
Unlike sublingual buprenorphine, Sublocade can’t simply be stopped before a surgery. The depot injection continues releasing medication for weeks to months after your last shot, so the blocking effect persists whether or not you want it to in that moment. This is part of what makes it effective for treating opioid use disorder, but it requires advance planning around any situation where opioid-based pain relief might be needed.