Tuesday, July 19, 2011

Buprenorpine Implants

Peter R. Coleman, M.D.

The Buprenorphine Implants are made by a small pharmaceutical company called Titan Pharmaceuticals, and Titan supplied funding for the study. The implants last over 6 months. The usual dose is 4 or 5 implants and this dose delivers steady, but quite low levels of buprenorphine – about the equivalent of 1 mg daily of the oral, sublingual dose.  The trial was conducted in 2007 and 2008 and involved 168 adults. Patients received either 4 active implants or 4 placebo implants. They were allowed to take extra sublingual Buprenorphine (Suboxone) if they felt bad or had cravings, and if they kept using the extra Suboxone they were able to get a fifth implant, if they wanted it. The whole trial was double blind, so neither the patients nor the staff studying them knew who got the real implants.

The two main study outcomes they were looking at were to see if patients with the real implants stayed in treatment longer and whether they had less urine drug screens that were positive for opiates.

The results did show that the active Buprenorphine Implants worked better than the placebo ones. As far as staying in the study goes, 66% of the patients with the real implants completed the study, but only 31% of the patients with the fake implants completed the study. Also the patients with the real implants had less positive urine drug tests – 60% versus 72% of the patients who had the placebo implants. The patients with the real implants also reported fewer cravings and they had fewer withdrawal symptoms.

Over all, the drug company was happy with the results and felt that the study showed that the new implants can be helpful to patients trying to deal with their opiate addiction. In fact, the number of patients staying in treatment with these Buprenorphine implants is considerably better than patients who take regular sublingual Suboxone. Results from previous studies of patients who take regular Suboxone show that only about 35 - 50% of them stay in treatment for the whole 6 months. And, the implants do eliminate the problem of patients skipping their dose so they can get high or selling their Suboxone on the street.

Of course, one thing the study didn’t address is the difficulty patients have when it is time to get off their Buprenorphine  – either in the Implant or in regular Suboxone. As mentioned earlier, we are seeing more and more patients who just can’t stand the long and intense withdrawal symptoms coming off Suboxone. Fortunately our Accelerated Opiate Detox (AOD) program works very well for these patients.

Here at TCI we use Naltrexone implants, to help patients stay off opiates, and I have to say that when I look at a study like this I am more and more delighted with the treatment we offer. In this study, the patients who got the real implants still had drug tests that were positive for opiates 60% of the time. This means that over half the time these patients were still using drugs! This is hardly what we want from a treatment program. I guess it not surprising that 65% of the patients dropped out and didn’t complete the study – presumably because they were back using drugs.

In contrast, Naltrexone implants work much better. We do not have the resources to do long term studies on our implants, but a number of other groups have done these types of long term outcome studies. In general, the studies using Naltrexone Implants show that about 60% of patients are completely off opiates at 12 months. Their drug screens are all negative because while patients have Naltrexone implants in place they are unable to get any benefit from using opiate drugs.

In fact, I met the staff from Titan pharmaceuticals a few years ago at a conference and I asked them why they were working on a 6 month Buprenorphine implant and not working on a 6 month Naltrexone implant. I was told that the company had decided there was a better market for the Buprenorphine implant. I wish they would re-consider and develop a reliable 6 month Naltrexone implant that really would help patients stay clean.

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