Safe Combination of Flexeril (Cyclobenzaprine) with Suboxone (Buprenorphine/Naloxone)
The combination of Flexeril (cyclobenzaprine) with Suboxone (buprenorphine/naloxone) should be used with extreme caution due to the risk of additive central nervous system depression, and doses should be reduced to minimize this risk.
Understanding the Medications
Suboxone
- Contains buprenorphine (partial mu-opioid receptor agonist) and naloxone in a 4:1 ratio
- Used for opioid dependence treatment
- Standard dosing ranges from 4-24 mg daily (buprenorphine component) 1
- Has CNS depressant effects
Flexeril (Cyclobenzaprine)
- Muscle relaxant with sedating properties
- Acts as a central nervous system depressant
Risk Assessment
The primary concern when combining these medications is the potential for additive central nervous system (CNS) depression, which can lead to:
- Excessive sedation
- Respiratory depression
- Cognitive impairment
- Increased risk of accidents/falls
Dosing Recommendations
When combining these medications, consider the following approach:
Start with reduced doses of cyclobenzaprine:
- Begin with 5 mg of cyclobenzaprine (lower than standard 10 mg dose)
- Limit to once daily, preferably at bedtime
- Monitor for excessive sedation before increasing frequency
Maintain stable Suboxone dosing:
- Do not adjust Suboxone dosing when initiating cyclobenzaprine
- Patients should be on a stable Suboxone regimen before adding cyclobenzaprine
Titration protocol:
- After 3-5 days of combined therapy without excessive sedation, consider increasing cyclobenzaprine to standard dosing if needed
- Maximum daily dose of cyclobenzaprine should not exceed 20 mg when used with Suboxone
- Divided doses (e.g., 5 mg TID) may be safer than larger single doses
Monitoring Requirements
Patients on this combination should be monitored for:
- Excessive sedation or somnolence
- Changes in respiratory rate or depth
- Cognitive impairment
- Signs of serotonin syndrome (though rare, both medications can affect serotonergic pathways)
- Motor and cognitive function 1
Special Considerations
- Avoid additional CNS depressants: The FDA recommends careful medication management when combining Suboxone with other CNS depressants 1
- Elderly patients: Use even lower starting doses (2.5 mg of cyclobenzaprine)
- Liver impairment: Both medications are metabolized by the liver; consider further dose reductions in patients with hepatic impairment
Warning Signs to Monitor
If any of the following occur, discontinue cyclobenzaprine immediately:
- Excessive sedation that interferes with daily activities
- Respiratory rate < 12 breaths per minute
- Confusion or significant cognitive impairment
- Inability to be easily aroused
Alternative Approaches
If muscle spasm relief is needed in patients on Suboxone, consider:
- Non-pharmacological approaches (physical therapy, heat/cold therapy)
- NSAIDs if not contraindicated
- Topical muscle relaxants
- Reduced frequency of cyclobenzaprine (e.g., bedtime only)
This cautious approach to combining these medications prioritizes patient safety while still allowing for management of muscle spasms in patients requiring Suboxone therapy for opioid dependence.