Sublocade
Sublocade
Generic Name
Sublocade
Mechanism
- Buprenorphine is a high‑affinity, partially agonistic ligand at the μ‑opioid receptor (MOR) and an antagonist at the κ‑opioid receptor.
- It produces analgesia and euphoria similar to full agonists but has a *ceiling effect* on respiratory depression.
- Rapid dissociation of other opioids from MOR prevents withdrawal progression, allowing *maintenance* therapy.
- The microsphere matrix grants controlled, sustained release, maintaining therapeutic serum levels for ~30 days.
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Pharmacokinetics
- Route & Absorption: SC injection → slow, predictable release; peak concentration (Cmax) occurs 5–10 days post‑dose; steady‑state achieved after 4–6 months of monthly dosing.
- Bioavailability: ~91 % of IM; SC yields ~80 %.
- Half‑life: ~12–17 days (effective release half‑life).
- Clearance: Hepatic *CYP3A4* metabolism; renal excretion of unchanged drug ~25 %.
- Drug–Drug Interactions: Potentiation with CNS depressants (benzodiazepines, alcohol); ↓CYP3A4 inhibitors increase plasma levels; CYP3A4 inducers reduce efficacy.
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Indications
- Maintenance treatment of chronic opioid dependence in adults when administered as a once‑monthly SC injection.
- Indicated *only* for patients who have previously stabilized on oral buprenorphine or methadone and who are in mild‑to‑moderate withdrawal at initiation.
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Contraindications
| Contraindication | Issue |
| Active opioid withdrawal | Risk of respiratory depression and precipitated withdrawal |
| Severe respiratory disease (COPD, sleep apnea) | Enhanced risk of respiratory compromise |
| CYP3A4 potent inducers (e.g., rifampin) | Reduced efficacy |
| Pregnancy (Category C) | Limited data; weigh benefit vs. unknown risk |
| *Severe hepatic impairment* | Unclear safety; monitor closely |
Warnings
• Respiratory depression: May occur if combined with other CNS depressants.
• Precipitated withdrawal: Initiate only after adequate washout from short‑acting opioids.
• Injection site reactions: Stiffness, swelling, or pain may develop; avoid over‑use of local anesthetics.
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Dosing
1. Initiation
• First 4 weeks: Daily oral buprenorphine (6–8 mg) to reach maintenance level and avoid withdrawal.
• Day 29: First SC dose of 25 mg (Sublocade).
2. Maintenance
• 25 mg SC once monthly (≤31 days).
3. Technique
• Injection sites: Abdomen, outer thigh, or upper arm (≥4 cm from joint).
• Bio‑secure: Use a 5‑mm needle; aspirate before injection to avoid intramuscular delivery.
4. Re‑dosing
• Can administer up to 30 days after the last injection if adherence lapses.
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Adverse Effects
| Common | Serious | Management |
| Injection‑site pain, swelling, erythema | Respiratory depression | Monitor vital signs; naloxone if needed |
| Constipation, nausea, diarrhea | Severe allergic reaction (anaphylaxis) | Antispasmodics, antihistamines; emergency care |
| Headache, dizziness | Severe hypotension | Hydration, positioning |
| Sleep disturbances | Ocular changes (rare) | Ophthalmology referral |
| Mood changes (anxiety, depression) | Cardiac arrhythmias (rare) | Psychiatric evaluation |
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Monitoring
- Clinical: Withdrawal assessment tools (SOWS/BRENDA) at each visit.
- Vitals: Respiratory rate, pulse, BP on every injection visit.
- Laboratory: Routine CBC, CMP at baseline; liver enzymes if underlying hepatic disease.
- Drug screening: Urine drug screen for ongoing opioid use or polydrug abuse.
- Adverse Effects: Document injection‑site reactions, constipation, nausea.
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Clinical Pearls
- 🚀 Better adherence – Monthly dosing eliminates daily pill burden, reducing diversion risk and improving treatment retention.
- ⛔ Avoid premature initiation – Start only after at least 4–6 weeks of oral buprenorphine or methadone to avoid withdrawal.
- 🌬️ CNS depressants – Never co‑administer high‑dose benzos or alcohol; patient education on overdose risk is critical.
- 📦 Storage – Keep at 2–8 °C; freeze‑thaw cycles to be avoided, ensuring consistent microsphere integrity.
- 📋 Insurance & cost – Verify prior authorization; many payers require demonstrated oral buprenorphine trial before coverage.
- 🩺 Buprenorphine dosing – The SR formulation can reduce peak plasma spikes, resulting in fewer dose‑related side effects compared to oral.
- 🔄 Switching to oral – Patients may switch back to oral buprenorphine if monthly injections are contraindicated, but do not discontinue abruptly.
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