Both Brixadi and Sublocade are extended-release, injectable forms of buprenorphine used for medication-assisted treatment (MAT) of moderate to severe opioid use disorder (OUD). Because they share the same active ingredient, their common and serious side effects are largely comparable. However, there are some differences related to their specific delivery systems and dosing regimens. This guide explores the potential adverse effects of both medications.
Common Side Effects
Many of the less severe side effects are a normal part of adjusting to buprenorphine treatment. These are typically mild and manageable but should be monitored. The most commonly reported adverse events for both Brixadi and Sublocade include:
- Injection site reactions: Pain, redness (erythema), itching (pruritus), swelling, and irritation are very common due to the medication being injected under the skin. A lump or nodule may also form at the injection site as the medication depot releases over time.
- Gastrointestinal issues: Constipation and nausea are frequent complaints. Some patients may also experience vomiting or abdominal discomfort.
- Headache: This is one of the most reported side effects for both medications.
- Fatigue and drowsiness: Feeling tired, sleepy, or experiencing some sedation is common, especially in the initial phase of treatment or following a dose increase.
- Sleep disturbances: Insomnia or trouble sleeping can occur.
Other less common, but still possible, side effects include back pain, dizziness, and urinary tract infections.
Serious Warnings and Risks
Both Brixadi and Sublocade carry significant warnings due to the nature of buprenorphine and their extended-release formulation. These require careful management and patient education from a healthcare provider.
- Risk of Serious Harm or Death with Intravenous Administration: Both medications have a Boxed Warning from the FDA. The formulations form a solid mass upon contact with body fluids, and injecting them into a vein can cause severe harm, including occlusion of blood vessels, local tissue damage, and life-threatening pulmonary emboli. To mitigate this risk, both drugs are only available through a restricted Risk Evaluation and Mitigation Strategy (REMS) program, and injections must be administered by a certified healthcare professional.
- Respiratory Depression: Buprenorphine, as an opioid, can cause life-threatening respiratory depression (slowed breathing). This risk is significantly increased when the medication is used with other central nervous system depressants, including alcohol, benzodiazepines, and other opioids. Patients should discuss having naloxone available for emergency use.
- Liver Problems: Cases of liver injury, including hepatitis, have been reported. Healthcare providers should monitor liver function with blood tests before and during treatment. Symptoms like yellowing of the skin or eyes (jaundice), dark urine, and abdominal pain should be reported immediately.
- Adrenal Insufficiency: Long-term use of opioids, including buprenorphine, can lead to adrenal gland problems. This condition may manifest as nausea, vomiting, dizziness, and unusual weakness.
- Allergic Reactions: Severe allergic reactions, such as anaphylactic shock, can occur, though they are rare. Symptoms may include hives, swelling of the face, and difficulty breathing. The needle cap for Brixadi contains latex, which may cause allergic reactions in latex-sensitive individuals.
- Neonatal Opioid Withdrawal Syndrome: Prolonged use during pregnancy can lead to a potentially life-threatening withdrawal syndrome in newborns.
Managing Side Effects and When to See a Doctor
Many common side effects can be managed with simple strategies:
- Constipation: Increasing fluid intake, dietary fiber, and light exercise can help. Over-the-counter laxatives can also be discussed with a healthcare provider.
- Drowsiness: Avoid driving or operating heavy machinery until you know how the medication affects you. Drowsiness often lessens as your body adjusts.
- Injection Site Issues: Do not rub or massage the injection site, as this can interfere with the medication's release. Rotating injection sites is recommended.
- Nausea: Taking the medication with food or using prescribed anti-nausea medication can help.
Contact a healthcare provider immediately for any sign of serious side effects, such as:
- Signs of an allergic reaction (swelling, hives, breathing trouble).
- Yellowing of the skin or eyes.
- Slow, shallow, or difficult breathing.
- Severe dizziness or fainting.
- Extreme fatigue, lack of appetite, or nausea/vomiting.
Comparison of Brixadi and Sublocade Side Effects
| Feature | Brixadi | Sublocade |
|---|---|---|
| Dosing Frequency | Weekly or monthly injections | Monthly injections only |
| Injection Sites | Abdomen, thigh, buttock, or upper arm (depending on dosing) | Abdomen only |
| Active Ingredient | Buprenorphine | Buprenorphine |
| Common Side Effects | Injection site reactions, headache, constipation, nausea, insomnia | Injection site reactions, headache, constipation, nausea, drowsiness |
| Serious Side Effects | Respiratory depression, liver issues, adrenal insufficiency, allergic reactions, IV injection risk (Boxed Warning) | Respiratory depression, liver issues, adrenal insufficiency, allergic reactions, IV injection risk (Boxed Warning) |
| Withdrawal After Discontinuation | Possible for months after the last injection, requiring supervision | Possible for months after the last injection, requiring supervision |
| Risk of Diversion | Low, due to healthcare provider administration | Low, due to healthcare provider administration |
Conclusion
Brixadi and Sublocade are effective treatment options for OUD, leveraging the same active ingredient to reduce cravings and withdrawal symptoms. As a result, their side effect profiles are very similar, with differences primarily arising from administration specifics like dosing frequency and injection site. Both carry significant warnings, most notably the risk of severe harm if injected intravenously and life-threatening respiratory depression, particularly when combined with other CNS depressants. Patients and healthcare providers should carefully consider these risks and discuss management strategies, including the use of naloxone, as part of a complete treatment plan. Ongoing monitoring and clear communication are essential for a safe and successful treatment journey. For more detailed safety information, patients should consult the official FDA prescribing information or visit the official REMS websites, such as the SUBLOCADE REMS program.
