Conversion from 8 mg Daily Suboxone to Weekly Brixadi
For a patient on 8 mg daily Suboxone, the corresponding weekly Brixadi dose is 16 mg subcutaneous injection 1.
Direct Conversion Protocol
The FDA-approved Brixadi prescribing information provides explicit conversion guidance for patients switching from transmucosal buprenorphine products 1:
- Daily sublingual buprenorphine 8-10 mg → Weekly Brixadi 16 mg
This conversion can be performed directly without tapering or washout period. The patient receives their last dose of Suboxone and then begins weekly Brixadi 16 mg injections at 7-day intervals 1.
Key Clinical Considerations
Bioavailability advantage: Brixadi demonstrates 5.7- to 7.7-fold greater buprenorphine bioavailability compared to sublingual formulations 2. This enhanced bioavailability is already accounted for in the FDA conversion table, so no additional dose adjustment is needed.
Pharmacokinetic profile: After subcutaneous injection, Brixadi reaches peak concentration (Tmax) at approximately 24 hours for the weekly formulation, with a terminal half-life of 5 days 2. This provides sustained therapeutic levels throughout the weekly dosing interval.
Steady-state timing: Patients achieve steady-state plasma concentrations after approximately 4 weeks of weekly Brixadi dosing 1. During this initial period, monitor for signs of under- or over-medication.
Dose Adjustment Strategy
If the patient requires dose modification after initiating weekly Brixadi 16 mg 1:
- Upward titration: Can increase to 24 mg weekly (maximum 32 mg weekly)
- Additional dosing: An extra 8 mg injection may be administered during any dosing interval if clinically indicated, waiting at least 24 hours after the previous injection
- Timing of adjustments: Dosage changes can be made at weekly appointments based on clinical response
Alternative Monthly Formulation
For patients preferring less frequent dosing, weekly Brixadi 16 mg converts to monthly Brixadi 64 mg 1. However, the monthly formulation should only be used after the patient has been stabilized on transmucosal buprenorphine—it is not intended for buprenorphine-naive patients 1.
Administration Requirements
Critical safety point: Brixadi is only available through a REMS program and must be administered by a healthcare provider in a certified healthcare setting 1. The medication cannot be dispensed directly to patients due to the risk of serious harm or death from intravenous self-administration 1.
Route: Subcutaneous injection only—never intravenous, intramuscular, or intradermal 1. The medication forms a liquid crystalline gel upon contact with body fluids, which could cause life-threatening pulmonary emboli if administered intravenously 1.
Clinical Evidence
The conversion approach is supported by a randomized controlled trial demonstrating that weekly subcutaneous buprenorphine depot was non-inferior to daily sublingual buprenorphine/naloxone, with the depot formulation actually showing superior results on cumulative distribution function analysis of opioid-negative urine samples (26.7% vs 0%, P=0.004) 3. Injection site adverse events were comparable between groups and none were severe 3.
Recent real-world data confirms that transitions to long-acting injectable buprenorphine within 24 hours of the last sublingual dose are feasible and well-tolerated, with short-term retention rates exceeding 60% and minimal withdrawal symptoms 4.