Friday, February 21, 2014

Researchers Take a Novel Approach to Vivitrol Induction

Researchers and clinicians at Duke University performed a small, open label study to test a new induction protocol for opioid detoxification in an outpatient setting. Much has been written about the pros and cons of antagonist medication for opioid dependence, with most evidence supporting agonist medications like buprenorphine or methadone. One of the most difficult aspects of maintenance antagonist treatment is the detoxification and induction phases of treatment, considering the intolerability of the experience to most patients - especially those in outpatient settings. So, the authors of a new study, published recently in Drug and Alcohol Dependence, sought to make this experience a little more tolerable. The administered increasing doses of naltrexone and decreasing doses of buprenorphine to treatment-seeking opioid addicts until their first dose of extended-release injectable naltrexone (Vivitrol). The results were encouraging:



The approval of extended release injectable naltrexone (XR-NTX; Vivitrol®) has introduced a new option for treating opioid addiction, but studies are needed to identify its place within the spectrum of available therapies. The absence of physiological opioid dependence is a necessary and challenging first step for starting XR-NTX. Outpatient detoxification gives poor results and inpatient detoxification is either unavailable or too brief for the physiological effects of opioids to resolve. Here we present findings from an open label study that tested whether the transition from opioid addiction to XR-NTX can be safely and effectively performed in an outpatient setting using very low dose naltrexone and buprenorphine.


Twenty treatment seeking opioid addicted individuals were given increasing doses of naltrexone starting at 0.25 mg with decreasing doses of buprenorphine starting at 4 mg during a 7-day outpatient XR-NTX induction procedure. Withdrawal discomfort, craving, drug use, and adverse events were assessed daily until the XR-NTX injection, then weekly over the next month.


Fourteen of the 20 participants received XR-NTX and 13 completed weekly assessments. Withdrawal, craving, and opioid or other drug use were significantly lower during induction and after XR-NTX administration compared with baseline, and no serious adverse events were recorded.


Outpatient transition to XR-NTX combining upward titration of very low dose naltrexone with downward titration of low dose buprenorphine was safe, well tolerated, and completed by most participants. Further studies with larger numbers of subjects are needed to see if this approach is useful for naltrexone induction.

Mean opioid withdrawal and craving scores during induction and after naltrexone extended release administration (Days 1-9), using SOWS (Subjective Opioid Withdrawal Scale), COWS (Clinical Opioid Withdrawal Scale) and VAS (Visual Analog Scale) for craving. Time point scores are the results of the mean score of each day of treatment, error bars represent + -1 SEM. Number of participants is reported on the X-axis.

In-treatment proportion of opioid positive urine samples (Day1-9, N = 20).


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