Sublocade and Suboxone both deliver buprenorphine to treat opioid use disorder, but they do it in fundamentally different ways. Suboxone is a sublingual film or tablet you take daily, dissolving it under your tongue. Sublocade is a monthly injection given by a healthcare provider, forming a slow-releasing depot under the skin that maintains steady buprenorphine levels for weeks. That difference in delivery shapes nearly everything about what each medication feels like to use, how it interacts with daily life, and who it works best for.
How They Get Buprenorphine Into Your System
Suboxone contains buprenorphine combined with naloxone, which is included to discourage misuse. When you place the film or tablet under your tongue, buprenorphine absorbs through the oral lining and reaches peak blood levels within about 45 minutes to an hour.1PubMed Central. Pharmacokinetics of Sublingual Buprenorphine Tablets Following Single and Multiple Doses in Chinese Participants With and Without Opioid Use Disorder The naloxone component is poorly absorbed sublingually, so it mostly passes through without effect when taken as prescribed. If someone tried to inject the combined tablet, however, the naloxone would become active and trigger withdrawal.
Sublocade works differently. A healthcare provider injects a buprenorphine solution mixed with a polymer that solidifies into a small depot under the skin of your abdomen. That depot slowly dissolves over weeks, releasing buprenorphine continuously. Pharmacokinetic modeling shows the absorption from this depot follows a more complex path than the simple spike-and-fade of a sublingual dose, maintaining more consistent drug levels throughout the month.2PubMed Central. Population Pharmacokinetics of a Monthly Buprenorphine Depot Injection for the Treatment of Opioid Use Disorder: A Combined Analysis of Phase II and Phase III Trials There is no naloxone in Sublocade because diversion risk is essentially zero; you cannot extract the drug from a depot sitting under someone’s skin.
One practical consequence of sublingual dosing is that buprenorphine absorption is not perfectly efficient. As you increase the sublingual dose, you do not get a proportional increase in blood levels. Doubling the dose does not double the amount of drug reaching the bloodstream.3PubMed. Pharmacokinetics and subjective effects of sublingual buprenorphine, alone or in combination with naloxone: lack of dose proportionality Sublocade bypasses this ceiling effect by delivering buprenorphine directly into tissue rather than relying on oral absorption.
What the Clinical Trials Show About Effectiveness
Head-to-head trials consistently find that Sublocade performs at least as well as sublingual buprenorphine in reducing opioid use. Across trials, the injectable formulations were found to be non-inferior to sublingual buprenorphine and more effective than placebo.4PubMed. Buprenorphine treatment for opioid use disorder: recent progress A systematic review found that long-acting injectable buprenorphine was positively associated with improvements in abstinence rates and patient-centered outcomes.5PubMed. Effectiveness of long-acting buprenorphine – A systematic review
The phase 3 trial that led to Sublocade’s approval compared two dosing regimens against placebo over 24 weeks. Participants receiving Sublocade achieved roughly eight times the rate of opioid abstinence compared to placebo, with about 41 to 43 percent abstinence versus 5 percent for placebo.6The Lancet. Health-related quality of life and patient-reported outcomes in participants of a buprenorphine monthly depot (BUP-XR) randomised, double-blind, placebo-controlled, phase 3 study These numbers matter because they confirm the injection delivers enough buprenorphine to meaningfully suppress opioid use, even without the discipline of daily dosing.
A large pragmatic trial in Norway and Australia randomized people with opioid use disorder to either extended-release buprenorphine or standard-of-care medication (which included sublingual buprenorphine or methadone). People with more severe opioid problems at the start of the trial actually showed a relatively greater treatment effect with the injectable form, suggesting Sublocade may particularly benefit people who are struggling most.7The Lancet. Extended-release buprenorphine versus standard-of-care medication for opioid use disorder
The Complicated Picture on Retention
You might assume that a monthly injection would keep people in treatment longer than a daily medication, since it removes the burden of remembering to dose every day. The reality is messier. A large analysis of commercially insured Americans found that sublingual buprenorphine retention was actually significantly higher at every time point. At six months, about half of people on sublingual buprenorphine were still in treatment, compared to roughly one in seven on the extended-release injection. At twelve months, the gap widened further.8PubMed Central. Retention and dropout from sublingual and extended-release buprenorphine treatment: A comparative analysis of data from a nationally representative sample of commercially-insured people with opioid use disorder in the United States
That might sound damning for Sublocade, but context matters. People switching to monthly injections often face insurance barriers, prior authorization delays, and the need to physically show up at a clinic that stocks and administers the medication. Sublingual buprenorphine, by contrast, can be prescribed through telehealth and picked up at a pharmacy. The retention gap likely reflects these logistical and access hurdles more than the medication’s clinical performance. An Ontario population-based cohort found that the median time to discontinuation of extended-release buprenorphine was about six months, with no significant differences between urban and rural populations.9Drug and Alcohol Dependence. Characteristics, treatment patterns and retention with extended-release subcutaneous buprenorphine for opioid use disorder: A population-based cohort study in Ontario, Canada
Meanwhile, a smaller retrospective review of a single treatment program found the opposite pattern: retention increased after people switched from sublingual tablets or films to injectable buprenorphine.10The Journal for Nurse Practitioners. Brief Report Evaluating Retention Rates in a Medication-Assisted Treatment Program The takeaway is that retention depends heavily on the healthcare system around the medication, not just the medication itself.
Craving and Withdrawal Suppression
Both medications suppress opioid cravings and withdrawal symptoms effectively. A randomized trial directly comparing depot buprenorphine injections to daily sublingual buprenorphine with naloxone found that craving and withdrawal were suppressed immediately in both groups from day one and remained suppressed throughout the study, without significant differences between groups.11JAMA Internal Medicine. Weekly and Monthly Subcutaneous Buprenorphine Depot Formulations vs Daily Sublingual Buprenorphine With Naloxone for Treatment of Opioid Use Disorder: A Randomized Clinical Trial
Where Sublocade may have an edge is in the steadiness of craving control. The Norwegian-Australian trial found that participants on extended-release buprenorphine were more likely to report zero craving scores on standardized measures compared to those on standard-of-care treatment.12The Lancet. Extended-release buprenorphine versus standard-of-care medication for opioid use disorder With sublingual dosing, blood levels peak and then decline each day, and some people notice a return of cravings in the hours before their next dose. The injection avoids those daily fluctuations entirely.
Side Effects That Differ Between the Two
Both medications share the general side effects of buprenorphine: constipation, headache, nausea, and sleep disturbances. The differences relate mostly to the route of delivery.
Sublocade introduces injection-site reactions that sublingual formulations obviously do not have. Most are mild: a firm lump under the skin, some redness, itching, or tenderness at the injection site. These usually resolve on their own. In rare cases, however, more serious problems can occur. A review identified eight cases of skin necrosis or related skin changes following subcutaneous buprenorphine injections, with patients reporting pain, redness, hardening of the skin, and swelling.13International Journal of Addiction Nursing. Necrosis or Related Skin Changes After Subcutaneous Injection of Buprenorphine Extended-Release At least one case required surgical removal of the depot.14PubMed. Skin Necrosis Following Inadvertent Dermal Injection of Extended-release Buprenorphine These events are rare but worth knowing about.
Suboxone has its own distinctive concern: dental health. Because sublingual buprenorphine dissolves in the mouth, it concentrates in saliva and salivary glands. Research has shown that buprenorphine and its metabolites at the concentrations found in oral fluid after sublingual dosing can significantly increase the growth of the bacteria most responsible for tooth decay.15PubMed Central. Buprenorphine Salivary Gland Accumulation Sustaining High Oral Fluid Exposure and Increasing the Risk of Streptococcus mutans Biofilm Formation The FDA issued a warning about this in 2022 after receiving hundreds of reports of serious dental problems in people taking sublingual buprenorphine. Sublocade bypasses the mouth entirely, eliminating this particular risk.
Getting Started on Sublocade
You cannot walk into a clinic and receive a Sublocade injection cold. The standard protocol requires you to first stabilize on sublingual buprenorphine for at least a week. In the original registration trials, participants were inducted and stabilized on 8 to 24 mg of sublingual buprenorphine daily for seven to fourteen days before transitioning to the injection, ensuring they tolerated buprenorphine and experienced a reduction in withdrawal and cravings.16PubMed Central. Initiation and Dosing of Extended-Release Buprenorphine: A Narrative Review of Emerging Approaches for Patients Who Use Fentanyl The Sublocade prescribing information describes a seven-day period of stability on sublingual buprenorphine before the first injection.17PubMed Central. Inpatient Low Dose Transitions from Full Agonist Opioids Including Methadone onto Long Acting Depot Buprenorphine
However, newer approaches are being explored. Some clinical trials have tested rapid transitions directly to the injection using low-dose induction strategies, which is especially relevant for people using fentanyl. Because fentanyl is so potent and lingers in body fat, traditional buprenorphine induction can trigger severe precipitated withdrawal. Researchers are investigating ways to bridge people onto the injection more quickly, sometimes within an inpatient setting.
The Fentanyl Factor
The rise of illicit fentanyl has complicated opioid use disorder treatment in ways that affect both medications. Fentanyl’s potency means that standard buprenorphine doses sometimes feel insufficient, and traditional induction can be a rough experience. A recent trial specifically examined whether maintaining Sublocade at the higher 300 mg dose (rather than stepping down to 100 mg after the first two months, as originally designed) would help people who use fentanyl. While the overall primary outcome did not show a statistically significant difference between the two doses, people who specifically reported fentanyl use had greater reductions in opioid use when maintained on the higher 300 mg dose, without an increase in adverse events.18JAMA Network Open. Is High-Dose Extended-Release Buprenorphine Safe and Effective for Persons Who Use Fentanyl?
This is an area where Sublocade may offer a practical advantage. With sublingual Suboxone, there is a ceiling on how much buprenorphine your mouth can absorb in a single dose. Sublocade delivers the full dose directly into tissue, and clinical investigators are testing whether sustained high-dose exposure is the key to better outcomes in the fentanyl era.
Diversion Risk and Controlled Settings
One of the most frequently cited advantages of Sublocade is reduced diversion risk. Sublingual buprenorphine tablets and films can be stored, sold, or shared. This is not always a negative: some research suggests that diverted buprenorphine is often used by people self-treating withdrawal who lack access to formal care. But in settings like jails, prisons, and residential treatment programs, diversion is a serious operational concern. Long-acting injectable buprenorphine essentially eliminates that problem because the drug is locked in a depot under the skin.19Preventive Medicine. Long-acting buprenorphine injectables: Opportunity to improve opioid use disorder treatment among rural populations
A trial at a Rhode Island jail found that people who received extended-release buprenorphine before release had significantly better outcomes than those on daily sublingual buprenorphine. About 69 percent of the extended-release group were still on medication eight weeks after release, compared to 35 percent of the sublingual group. Rates of opioid-negative urine tests were also higher in the extended-release group.20JAMA Network Open. Findings from JCOIN’s New York University Research Hub Leaving jail with a depot already working in your body eliminates the critical gap where people have to find a new prescriber, fill a prescription, and get themselves to a pharmacy, all during the highest-risk period for overdose.
A larger randomized trial is now underway to further compare extended-release and sublingual buprenorphine among people detained pretrial, tracking not just medication continuation but also recidivism and death in the three months following release.21PubMed Central. A protocol for a randomized comparison of extended-release versus sublingual buprenorphine among pre-trial detainees in jail
Managing Acute Pain While on Sublocade
If you need surgery or experience an injury while on Suboxone, your doctor can adjust or pause your daily dose to make room for short-acting pain medications. For surgeries with minimal expected pain, the guidance is to simply keep taking buprenorphine as usual. For major surgeries, some guidelines recommend tapering down to a lower dose before the procedure to free up enough opioid receptor space for additional pain relief.22Pain Medicine. Perioperative Management of Buprenorphine: Solving the Conundrum
Sublocade makes this harder. You cannot simply stop or reduce a depot that is already under your skin. A scoping review found that most clinicians managing acute pain in people on Sublocade achieved adequate pain control by continuing the injection and layering on full opioid agonists alongside non-opioid options like anti-inflammatory drugs. In some cases, clinicians scheduled surgery during the last week of the injection cycle when buprenorphine levels were lowest. No cases of respiratory depression or toxicity were reported.23PubMed Central. Pain Management Strategies for Patients Receiving Extended-Release Buprenorphine for Opioid Use Disorder: A Scoping Review Pain management on Sublocade is doable, but it requires more coordination and planning than with sublingual buprenorphine.
Pregnancy
Buprenorphine is a standard treatment for opioid use disorder during pregnancy, and Suboxone (often just the buprenorphine-only sublingual tablet, without naloxone) has a longer track record in pregnant patients. Sublocade’s use during pregnancy is newer and less studied, but early evidence is reassuring. A randomized clinical trial comparing extended-release buprenorphine to sublingual buprenorphine from pregnancy through twelve months postpartum found no differences in the rate of infants needing opioid treatment for neonatal withdrawal, and no difference in the number of treatment days required.24JAMA Internal Medicine. Extended-Release vs Sublingual Buprenorphine in Pregnancy Through 12 Months Post Partum: A Randomized Clinical Trial
A separate observational study found that pregnancy and delivery complications did not differ between groups receiving extended-release buprenorphine and those on oral buprenorphine. The need for pharmacotherapy for neonatal withdrawal was numerically lowest in the extended-release group, though the difference did not reach statistical significance given the small sample sizes.25PubMed. Extended-release versus oral buprenorphine as opioid maintenance treatment during pregnancy-maternal and neonatal outcomes For pregnant patients who struggle with daily adherence or who are in unstable living situations, the monthly injection could reduce the risk of gaps in treatment during a critical period.
Cost and Access
Sublocade is more expensive upfront than generic sublingual buprenorphine. A UK-based trial estimated that extended-release buprenorphine cost about £1,033 more per patient than standard-of-care treatment, with only a small gain in quality-adjusted life. The probability that Sublocade was cost-effective at the UK’s standard willingness-to-pay threshold was only about 37 percent.26The Lancet. Extended-release buprenorphine versus standard-of-care medication for opioid use disorder However, cost analyses that look beyond medication price alone tell a different story. Among commercially insured patients in the United States, those who were adherent to extended-release buprenorphine had roughly $15,000 lower non-medication healthcare costs per person over a year compared to patients adherent to other forms of medication for opioid use disorder.27Frontiers in Public Health. Association between extended-release buprenorphine adherence and reduced healthcare costs among insured patients with opioid use disorder Those savings came from fewer emergency department visits, hospitalizations, and other healthcare encounters.
Access remains a significant barrier. Sublocade must be administered by a healthcare provider and shipped through a specialty pharmacy under a restricted distribution program. Many clinics, especially in rural areas, do not stock it. Sublingual buprenorphine, by contrast, can be prescribed via telehealth and filled at any pharmacy, which is one reason why its real-world retention numbers look better even if the medication itself is not inherently more effective.
What Happens When You Want to Stop
Tapering off sublingual buprenorphine is conceptually straightforward: you gradually reduce your daily dose over weeks or months. It can still be unpleasant, and relapse risk increases with each step down, but you have fine-grained control over the pace.
Stopping Sublocade has a built-in taper that some patients find remarkably smooth. Because the depot dissolves slowly, buprenorphine continues releasing for months after your last injection. A small observational study followed eleven people who stopped extended-release buprenorphine after a period of stability. At six months, ten of the eleven (about 90 percent) had successfully discontinued treatment without restarting long-term medication. Only one participant restarted due to withdrawal symptoms triggered by stressful life events, and no other participants required rescue medication or ancillary treatment throughout the study period.28Drug and Alcohol Dependence Reports. Discontinuing extended-release buprenorphine: Participant experiences from a mixed-methods observational study The gradual, self-tapering nature of the depot may ease the transition in a way that is harder to replicate with daily dosing, where each dose reduction is felt acutely.
Dental Health and Sublingual Buprenorphine
The dental risk associated with sublingual buprenorphine deserves its own discussion because it is something many patients and even some prescribers underestimate. Buprenorphine and its metabolites accumulate in salivary glands, leading to high concentrations in the mouth. At those concentrations, research shows the drug significantly promotes the growth of the cavity-causing bacterium that is most responsible for dental decay.29PubMed Central. Buprenorphine Salivary Gland Accumulation Sustaining High Oral Fluid Exposure and Increasing the Risk of Streptococcus mutans Biofilm Formation Patients on sublingual buprenorphine should take this seriously: rinsing with water after each dose, maintaining regular dental care, and discussing fluoride treatments with their dentist. For people who already have poor dental health, the switch to Sublocade removes this specific exposure entirely.