Morphine sulfate abuse-deterrent formulations for the treatment of chronic pain.

INTRODUCTION: Abuse-deterrent formulations have been developed to reduce inappropriate opioid use. The aim of this paper is to review existing literature about currently available morphine abuse deterrent formulations. Areas covered: The US FDA has currently attributed an 'abuse deterrent formulation' label to two different morphine compounds: an agonist/antagonist combination, and a morphine formulation with physical barrier. The combination of morphine sulfate and naltrexone showed bioequivalence with extended release morphine. Naltrexone was found in low levels or non-detectable in most of the patients. If the capsules are tampered, the orally available naltrexone would be released, causing a decreased euphoria expected by the use of morphine. The application of physical and chemical barriers to the active compound aims at preventing manipulation of the opioid tablet. This abuse deterrent formulation obtained with a physical barrier did not reduce drug liking compared to ER morphine. Expert Commentary: Available data from literature suggest that both formulations may offer an alternative with lower abuse potential in the treatment of chronic pain. Nevertheless, current evidence suggests that only a little percentage of abusers may stop abusing drugs as result of reformulation. More post-marketing studies are advocated to evaluate the real impact of abuse deterrent formulations.