Can You Take Oxycodone with METHOCARBAMOL?

Severity assessment

Major. Concomitant use significantly increases the risk of profound sedation, respiratory depression, coma, and death due to additive central nervous system (CNS) depressant effects.

Mechanism (plain English)

Both methocarbamol and oxycodone work by slowing down the activity of the brain and spinal cord, which are parts of your central nervous system. Methocarbamol is a muscle relaxant that causes general CNS depression, helping to relieve muscle spasms. Oxycodone is a strong pain reliever (an opioid) that also depresses the CNS, reducing pain perception. When taken together, their individual depressant effects are added, leading to a much greater slowdown of brain activity. This can result in excessive drowsiness, slowed breathing, and a reduced level of consciousness.

Evidence level

Regulator-flagged. This interaction is highlighted in product information from regulatory bodies such as the U.S. Food and Drug Administration (FDA) and the Australian Therapeutic Goods Administration (TGA).

Top regulator advisories (cite verbatim or close paraphrase)

• TGA (Australia): "Concomitant use of opioids and benzodiazepines or other CNS depressants, including alcohol, may result in sedation, respiratory depression, coma, and death. Limit dosages and durations to the minimum required; and monitor patients for signs and symptoms of respiratory depression and sedation. Caution patients not to drink alcohol while taking [Product]." [1]
• MHRA / NICE (UK): No pair-specific public advisory found. However, general guidance for opioids and CNS depressants would apply.
• FDA (US): For methocarbamol: "Since methocarbamol may possess a general CNS depressant effect, patients receiving robaxin® or robaxin®-750 should be cautioned about combined effects with alcohol and other CNS depressants." [2] For oxycodone: "Concomitant use of opioids with benzodiazepines or other central nervous system (CNS) depressants, including alcohol, may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing for use in patients for whom alternative treatment options are inadequate." [3]
• EMA (Europe): No specific advisory for this pair found.

Clinical risk factors that elevate the danger

• Elderly patients: May be more sensitive to CNS depressant effects and have reduced drug clearance.
• Patients with respiratory impairment: Conditions like COPD or asthma increase the risk of life-threatening respiratory depression.
• Higher doses: Increased doses of either methocarbamol or oxycodone amplify CNS depression.
• Concomitant use of other CNS depressants: Including alcohol, benzodiazepines, gabapentinoids, antihistamines, tricyclic antidepressants, antipsychotics, or cannabis.
• Opioid-naïve patients: Patients not accustomed to opioids are at higher risk of respiratory depression.

What a patient should be told

• Risk of severe drowsiness and breathing problems: Taking methocarbamol and oxycodone together can make you very sleepy and slow down your breathing to a dangerous level. This can lead to falling asleep and not being able to wake up, or even stop breathing.
• Do not stop suddenly: If you have been taking these medications regularly, do not stop them abruptly without talking to your doctor or pharmacist, as this can cause withdrawal symptoms.
• Watch for warning signs: Be aware of signs like extreme drowsiness, confusion, unusual dizziness, slow or shallow breathing, or difficulty waking up. If you experience any of these, seek immediate medical attention.
• Discuss alternatives: Talk to your doctor or pharmacist about whether there are safer alternative treatments for your condition, or if the doses of your current medications can be adjusted.
• Urgent care triggers: If you or someone with you experiences severe difficulty breathing, unresponsiveness, or extreme sedation that you cannot rouse them from, call emergency services immediately.

Top 3 sources (with full citation)

1. Therapeutic Goods Administration. Opioids: boxed warning and class statements. Australian Government Department of Health and Aged Care. 2019. Available at: https://www.tga.gov.au/resources/explore-topic/prescription-opioids-hub/opioids-boxed-warning-and-class-statements
2. U.S. Food and Drug Administration. ROBARIN (methocarbamol tablets, USP) 500 mg and 750 mg. Label. 2003. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2003/011011Orig1s070s071lbl.pdf
3. U.S. Food and Drug Administration. OXYCODONE HYDROCHLORIDE oral solution CII. Label. 2024. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/200535s023lbl.pdf

Notes for the reviewing pharmacist

This interaction is well-established and carries significant risk due to the additive CNS depressant effects of both drugs. Methocarbamol, while not an opioid, acts as a general CNS depressant, and its co-administration with opioids like oxycodone can lead to profound sedation and respiratory depression. Careful patient selection, dose titration, and comprehensive patient education are crucial. Emphasize the risks of combining with alcohol and other CNS depressants. Consider naloxone co-prescription for high-risk patients. Monitor for signs of over-sedation, especially in elderly or compromised patients. The lack of specific MHRA/NICE or EMA advisories for this exact pair does not diminish the clinical significance of the interaction, as the general warnings for CNS depressants and opioids apply across jurisdictions. The FDA and TGA advisories provide strong regulatory backing for the major severity assessment.

Source metadata JSON

{
  "pair": "methocarbamol + oxycodone",
  "severity": "Major",
  "evidence_level": "Regulator-flagged",
  "source_urls": "https://www.tga.gov.au/resources/explore-topic/prescription-opioids-hub/opioids-boxed-warning-and-class-statements;https://www.accessdata.fda.gov/drugsatfda_docs/label/2003/011011Orig1s070s071lbl.pdf;https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/200535s023lbl.pdf"
}