Methocarbamol with Morphine Interaction Details


Brand Names Associated with Methocarbamol

  • Methocarbamol
  • Robaxin®

Brand Names Associated with Morphine

  • Arymo® ER
  • Avinza®
  • Embeda® (as a combination product containing Morphine, Naltrexone)
  • Kadian®
  • Morphabond®
  • Morphine
  • MS Contin®
  • Oramorph® SR
  • Roxanol-T

Medical Content Editor
Last updated Nov 20, 2023


Curious for more information about this interaction?

Ask our pharmacists directly!

Reach out to us

Interaction Effect

Increased risk of respiratory and CNS depression


Interaction Summary

Reserve the concomitant use of morphine and CNS depressants for patients in whom alternatives are inadequate. If concomitant use is necessary, use the lowest dose and shortest duration necessary to achieve treatment goals. Consider using a lower dose of morphine or the CNS depressant and closely monitor for sedation and respiratory depression. If morphine/naltrexone combination is being initiated, start at one-third to one-half of the usual morphine/naltrexone dose . If Morphabond ER(TM) is being initiated, start at the lowest possible dose, 15 mg every 12 hours, and consider using a lower dosage of the concomitant CNS depressant .


Severity

Major


Onset

Unspecified


Evidence

Theoretical


How To Manage Interaction

Reserve the concomitant use of morphine and CNS depressants to patients for whom alternatives are inadequate. If concomitant use is necessary, use the lowest dose and shortest duration necessary to achieve treatment goals. Consider using a lower dose of morphine or the CNS depressant and closely monitor for sedation and respiratory depression. If morphine/naltrexone combination is being initiated, start at one-third to one-half of the usual morphine/naltrexone dose . If Morphabond ER(TM) is being initiated, start at the lowest possible dose, 15 mg every 12 hours, and consider using a lower dosage of the concomitant CNS depressant .


Mechanism Of Interaction

Additive CNS depression effects


Literature Reports

A) In a study, the rate of nonmedical use-related emergency department visits occurring between 2004 and 2011 and involving opioid analgesics and benzodiazepines significantly increased from 11 to 34.2 per 100,000. Drug overdose deaths due to prescribed and greater than prescribed doses of both drug classes also significantly increased from 0.6 to 1.7 per 100,000, and overdoses deaths due to benzodiazepines significantly increased from 18% to 31% .

B) In a prospective cohort study, the rate of overdose deaths involving the dispensing of both opioid analgesics and benzodiazepines was 10 times higher compared with dispensing of opioid analgesics alone (7 vs 0.7 per 10,000 person years) .

C) In a cohort study of data from 2004 to 2009, the risk of fatal overdose significantly increased by 2.33 fold in patients taking opioid analgesics with a history of a benzodiazepine prescription and increased by 3.86 fold in those with a current benzodiazepine prescription compared with those taking opioid analgesics without a history of a benzodiazepine prescription. The risk of drug overdose deaths increased with increasing daily doses of benzodiazepines .

Methocarbamol Overview

  • Methocarbamol is used with rest, physical therapy, and other measures to relax muscles and relieve pain and discomfort caused by strains, sprains, and other muscle injuries. Methocarbamol is in a class of medications called muscle relaxants. It works by slowing activity in the nervous system to allow the body to relax

See More information Regarding Methocarbamol

Morphine Overview

  • Morphine is used to relieve moderate to severe pain. Morphine extended-release tablets and capsules are only used to relieve severe (around-the-clock) pain that cannot be controlled by the use of other pain medications. Morphine extended-release tablets and capsules should not be used to treat pain that can be controlled by medication that is taken as needed. Morphine is in a class of medications called opiate (narcotic) analgesics. It works by changing the way the brain and nervous system respond to pain.

See More information Regarding Morphine

Return To Our Drug Interaction Homepage


Feedback, Question Or Comment About This Information?

Ask , our medical editor, directly! He's always more than happy to assist.


Definitions

Severity Categories

Contraindicated

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.


Major

This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.


Moderate

This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.


Minor

While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.


Onset

Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.

Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.


Evidence

Level of documentation of the interaction.

Established: The interaction is documented and substantiated in peer-reviewed medical literature.

Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.


How To Manage The Interaction

Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.

It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.


Mechanism Of Interaction

The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.


Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.

Where Does Our Information Come From?

Information for our drug interactions is compiled from several drug compendia, including:

The prescribing information for each drug, as published on DailyMED, is also used. 

Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.

The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.