A consult over the weekend highlighted the importance of reviewing some buprenorphine basics. Buprenorphine, is frequently perceived as a milder opioid due to its partial agonist activity at the mu-opioid receptor. However, this perception can be misleading, as buprenorphine exhibits significant potency in terms of analgesia and overall opioid effect.
BLUF: Buprenorphine is a potent opioid with significant analgesic properties and potential for adverse effects, particularly in individuals without opioid tolerance. Recognizing its high MME equivalence is crucial for safe prescribing and patient education.
Morphine Milligram Equivalents (MME):
The conversion factor for sublingual buprenorphine to morphine milligram equivalents (MME) is approximately 1 mg of buprenorphine equals 30 mg of oral morphine. Applying this conversion:
• 8 mg of sublingual buprenorphine ≈ 240 mg of oral morphine.
To contextualize this with other opioids:
• Hydrocodone: The MME conversion factor is 1, meaning 1 mg of hydrocodone is equivalent to 1 mg of morphine. Therefore, 240 mg of morphine is equivalent to 240 mg of hydrocodone.
• Oxycodone: The MME conversion factor is 1.5, indicating 1 mg of oxycodone is equivalent to 1.5 mg of morphine. Thus, 240 mg of morphine corresponds to approximately 160 mg of oxycodone.
Partial Agonist Profile and Clinical Implications:
Buprenorphine’s classification as a partial agonist at the mu-opioid receptor leads to a ceiling effect on certain adverse effects, notably respiratory depression. This means that beyond a certain dosage, increasing amounts do not proportionally increase respiratory depression risk. However, when it comes to analgesia, buprenorphine acts similarly to a full agonist, providing effective pain relief without a clear ceiling effect at therapeutic doses.
Effects on Opioid-Naïve Individuals:
For individuals without prior opioid tolerance, an 8 mg dose of buprenorphine (equivalent to 240 mg of morphine) can result in significant opioid effects, including:
• Profound sedation: Leading to drowsiness and impaired cognitive function.
• Nausea and vomiting: Common side effects due to opioid-induced gastrointestinal effects.
• Dysphoria or agitation: Potentially arising from its activity at kappa-opioid receptors.
Reference:
1. Johnson RE, Fudala PJ, Payne R. Buprenorphine: considerations for pain management. J Pain Symptom Manage. 2005;29(3):297-326. doi:10.1016/j.jpainsymman.2004.07.005.
2. The Role of Morphine Milligram Equivalents (MME) in Opioid Safety, Prescribing, and Research. NIH HEAL Initiative website. https://heal.nih.gov/news/events/MMEwebinar. Accessed October 5, 2023.
3. https://research-mme.wakehealth.edu/login