Today on SuboxForum people were writing about their experiences with different buprenorphine formulations. Doctors occasionally have patients who prefer brand medications over generics, but buprenorphine patients push brand-loyalty to a different level. The current thread includes references to povidone and crospovidone, compounds included in most medications to improve bioavailability. Some forum members suggested that their buprenorphine product wasn’t working because of the presence of crospovidone or povidone. Others shared their experiences with different formulations of buprenorphine and questioned whether buprenorphine products are interchangeable, and whether buprenorphine was always just buprenorphine, or whether some people respond better to one product or another.
My comments, including my observations about patient tolerance of specific buprenorphine products, are posted below.
Just to get some things straight about povidone and crospovidone (which is just another synthetic formulation of povidone), both compounds are NEVER absorbed, by anyone. They are part of a group of compounds called ‘excipients’, and are included in many medications to help with their absorption. They act as ‘disintegrants’– meaning they allow the medication to ‘unclump’ and dissolve in liquids, such as saliva or intestinal secretions.
Molecules tend to clump together, sometimes into crystals, sometimes into other shapes. A pile of powdered molecules molded, packed, and dried into pill form wouldn’t dissolve in the GI tract if not for povidone or other disintegrants. I remember reading somewhere about cheap vitamins that could be found in the stool, looking much the same as they did when they were swallowed. Not sure who admitted to doing the research for that article..
Buprenorphine IS buprenorphine. Period. The absorption isn’t affected much by excipients, because nobody ever complains that their Suboxone or buprenorphine won’t dissolve. Povidone or crospovidone are also added to increase the volume, because an 8 mg tab of buprenorphine would be the size of 100 or so grains of salt. Excipients like povidone and crospovidone also help some drugs dissolve, especially drugs that are fatty and don’t usually dissolve well in water-based solutions. This last purpose does NOT apply to buprenorphine, since buprenorphine is very water-soluble. Zubsolv is supposedly absorbed more efficiently in part because it dissolves very quickly, and maybe that is due to excipients.
I realize that when I write ‘bupe is bupe’ it sounds like I don’t believe those who complain about their medication. But honest, I work with people over this issue every day… I have an equal mix of people who insist Suboxone doesn’t work for them and people who insist ONLY Suboxone works for them. Today I was reading TIP 43– a guide about medication-assisted treatment put out by SAMHSA and the Feds that is over 300 pages long, very well-cited– in a section that cited studies about the psychological triggers for withdrawal symptoms. TIP 43 and other TIPs can be downloaded for free… just Google them. TIP 43 is primarily about methadone, but some of the information applies to methadone and buprenorphine. The pertinent section was around page 100, if I remember correctly.
The TIP information mirrored what I see in my practice. For years, I’ve noticed that patients will complain about withdrawal symptoms even at times when their buprenorphine levels are at their highest. Patients also report that their withdrawal symptoms go away ‘right away’ after dosing, when in fact buprenorphine levels won’t increase significantly for 45-60 minutes. People who have been addicted to opioids may remember how even severe withdrawal mysteriously disappeared as soon as oxycodone tabs were sitting on the table in front of them. The bottom lline– withdrawal experiences are remembered, and those memories are ‘replayed’ in response to triggers or other memories.
In my experience as a prescriber, I’ve come to believe that patients with an open mind will learn to tolerate any type of buprenorphine (the exception being the 1 patient I’ve met who developed hives from meds with naloxone– hives that appeared consistently on three distinct occasions). But withdrawal symptoms seem to be triggered, in many people, by the expectation of withdrawal symptoms. So someone convinced he will never tolerate Zubsolv, Bunavail, or Suboxone Film will probably never tolerate those medications.
As for buprenorphine, it IS just buprenorphine. Molecules with a certain name and structure are always identical to each other. They are not ‘crafted’ products like bookcases or tables; some buprenorphine molecules aren’t made with a quality inferior to other buprenorphine molecules. And once a molecule is in solution, I don’t see much role for excipients. Of course a tablet or strip could contain too much or too little active drug, but that is an FDA issue, not an excipient issue.