My Doctor Is Switching Me From Belcuca To Subutex For Pain

Answer

Hi Moe and thanks for reaching out to us. 

Your provider is choosing a non-traditional way to manage your pain (as sublingual buprenorphine is not FDA-approved to treat chronic pain), but I think there’s a good chance that this change can help if you have not found relief on your current regimen.

There are some concerns, however, which I detail in the sections below.

Belbuca And Subutex Contain The Same Drug

First, we have to define a few things.

Buprenorphine is a drug that comes in many forms, including an intramuscular injection, a transdermal patch, a sublingual film, and a buccal film.

Belbuca is a buccal film containing buprenorphine. The film is placed between your gums and cheek. It is available in the following dosages:

• 75 mcg
• 150 mcg
• 300 mcg
• 450 mcg
• 600 mcg
• 750 mcg
• 900 mcg
  

Subutex is a sublingual tablet containing buprenorphine that goes under your tongue. It is available as a 2mg (2,000 mcg) and 8mg (8,000mcg) tablet.

Buprenorphine For Chronic Pain

Although Subutex and Belbuca contain the same drug (buprenorphine), they are FDA-approved for different indications (and are different in other aspects, like dosage strength).

Subutex is FDA-approved to treat opiate dependence while Belbuca is FDA-approved to treat severe pain that requires around-the-clock opioid treatment for which alternative treatments aren't effective or an option.

Butrans, another form of buprenorphine (a transdermal patch) is also FDA-approved to treat severe pain.

For Subutex, the sublingual tablet, if that is being prescribed to you for chronic pain, it would be considered 'off-label' as it is not FDA-approved for this condition.

When used for chronic pain, buprenorphine has some advantages over traditional opioids:

• It is a 'partial' opioid mu agonist and has a lower risk of physical dependence than other opioids
• It has a 'ceiling effect' and has a lower risk of causing severe side effects, such as respiratory depression when compared to other opioids

Subutex Vs. Belbuca Absorption

Even though they contain the same drug, Belbuca and Subutex are not interchangeable. They come in very different strengths and are both absorbed into our system to different extents. As mentioned too, only Belbuca is approved for the treatment of pain. Subutex is not.

In regard to how these drugs are absorbed, about 55% of the Belbuca dose is absorbed, so about 82mcg makes it into your system (based on your stated dose of 150mcg).

About 30% of the Subutex dose is absorbed, so for an 8mg tablet (which is 8000mcg), you are absorbing a total of around  2.4mg (or 2,400mcg). This is quite a significant increase from what you have been taking.

Concerns With Subutex Dosing For Pain

When buprenorphine is used for pain, it is only FDA-approved for the following maximum daily dosages:

• Belbuca (buprenorphine buccal films): 900mcg every 12 hours
• Butrans (buprenorphine transdermal patches): 20mcg/hour patches

Subutex comes in dosages of buprenorphine far higher than what is FDA-approved for pain and as I wrote about in the section above, taking an 8mg tablet would result in quite a dose increase from what you were taking before.

Most sources recommend starting buprenorphine for pain at doses around 75mcg and titrating up as needed.

Concerns With Using Subutex And Oxycodone Together For Pain

As mentioned, it looks like your physician is choosing a non-traditional therapy here, not only by using Subutex off-label for pain but also by using it in conjunction with the opioid oxycodone.

It can often be a challenge for someone managing pain to be taking both buprenorphine and another opioid agonist, like oxycodone, since buprenorphine can lessen the effects of other opioids.

Buprenorphine binds very strongly to opioid receptors, which, in turn, leaves less room for oxycodone to attach to these receptors.

It's not uncommon for individuals taking buprenorphine who need additional pain control (say, after surgery or for other acute pain), to need higher doses, of stronger opioids. For example, some studies suggest that potent full opioid agonists, like hydromorphone and fentanyl, are options for individuals already taking buprenorphine who need additional pain relief.

What is uncommon is the fact that your provider is keeping you on oxycodone for what seems to be consistent use, and then is adding on buprenorphine. In general, individuals utilize buprenorphine solely for pain control and have other opioids added on for intermittent use only if needed.

Final Words

As a final thought here, I want to say that managing chronic pain can be quite tricky, and things often get more complicated when buprenorphine is being used.

The use of buprenorphine for chronic pain (aside from just opiate use disorder) is an emerging treatment option, and there isn't the level of experience with it yet to fully know what course of treatment is going to be most effective for someone.

In your situation, not only is your provider using a form of buprenorphine (Subutex) and a dose that is not generally used or supported (currently) for chronic pain, but they are combining it with oxycodone, which could have unpredictable effects (i.e., it could lessen the effect of oxycodone, but how much your pain relief is affected due to the also increasing dose of buprenorphine is unclear).

If your provider is not a pain management specialist and you cannot be closely monitored during this transition, I highly recommend you seek one out.

Overall, I do think that the therapy you have described has a chance of success and I hope that it works well for you. Just know there may need to be some dosage adjustments over time and be sure to keep in constant communication with your provider.