Drug interactions
Clonazepam + Methadone
Severity: Major
Clonazepam and Methadone: major interaction.
Last updated Sources: US FDA label
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Combining an opioid with a benzodiazepine can cause profound sedation, respiratory depression, coma and death, and this risk is the subject of regulatory boxed warnings. The danger is greatest at higher doses and in patients with respiratory disease or substance use.
What this interaction means in plain words
Clonazepam and Methadone can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Clonazepam belongs to Central Nervous System; Methadone belongs to Musculoskeletal.
Why it happens
Additive CNS and respiratory depression via opioid receptor and GABA-A receptor effects.
What to do
Avoid concurrent use where possible; if needed, use the lowest doses and shortest duration. Monitor sedation and respiratory function and counsel patients and caregivers on warning signs.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
Other interactions of Methadone
- Alvimopan + Methadone Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Methadone Contraindicated
- Droperidol + Methadone Contraindicated
- Ibutilide + Methadone Contraindicated
- Isocarboxazid + Methadone Contraindicated
- Lefamulin + Methadone Contraindicated
Other interactions of Clonazepam
- Calcium / magnesium / potassium / sodium oxybates + Clonazepam Contraindicated
- Clonazepam + Sodium oxybate Contraindicated
- Alfentanil + Clonazepam Major
- Alprazolam + Clonazepam Major
- Amobarbital + Clonazepam Major
- Belladonna and opium + Clonazepam Major
Frequently asked questions
Can I take Clonazepam with Methadone?
MediHelp rates the interaction as major. Clonazepam and Methadone can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Combining an opioid with a benzodiazepine can cause profound sedation, respiratory depression, coma and death, and this risk is the subject of regulatory boxed warnings. The danger is greatest at higher doses and in patients with respiratory disease or substance use.
How serious is the interaction between Clonazepam and Methadone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concurrent use where possible; if needed, use the lowest doses and shortest duration. Monitor sedation and respiratory function and counsel patients and caregivers on warning signs.
What other medicines interact with Methadone?
MediHelp also lists interactions of Methadone with, for example, Alvimopan, Calcium / magnesium / potassium / sodium oxybates, Droperidol. The full list is on the Methadone page.
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