Opioid Agonist and Antagonist Effects on Opioid Dependence
Summary
The purpose of this study is to examine the acute agonist and antagonist effects of a full opioid agonist medication, an opioid antagonist medication, and a partial opioid agonist medication in individuals who have different levels of physical opioid dependence.
Description
The pharmacological effects of opioids in opioid dependent individuals can vary as a function of the characteristics of the opioid being studied (e.g., whether it is an agonist, partial agonist, or antagonist; the dose administered; and the route of administration). Another important set of factors influencing the effects produced by opioids is the characteristics of the organism to which the opioid is being administered. One such characteristic is the level of physical dependence in individuals.
Participants in this study will be maintained on different dose levels of an opioid agonist (methadone). The participant will be challenged with a prototypic opioid agonist, antagonist, and a mixed agonist-antagonist with partial agonist features in order to determine the effects that each has on the human body.
Study Design
Allocation: Randomized, Control: Active Control, Endpoint Classification: Pharmacodynamics Study, Intervention Model: Parallel Assignment, Masking: Double-Blind, Primary Purpose: Treatment
Conditions
Opioid-Related Disorders
Intervention
Methadone, Full opioid agonist, Partial opioid agonist, Opioid antagonist
Location
Johns Hopkins University (BPRU) Bayview Campus
Baltimore
Maryland
United States
21224 6823
Status
Terminated
Source
National Institute on Drug Abuse (NIDA)
Results (where available)
Links
- Source: http://clinicaltrials.gov/show/NCT00142727
- Information obtained from ClinicalTrials.gov on July 15, 2010
Medical and Biotech [MESH] Definitions
Methadone
A synthetic opioid that is used as the hydrochloride. It is an opioid analgesic that is primarily a mu-opioid agonist. It has actions and uses similar to those of MORPHINE. It also has a depressant action on the cough center and may be given to control intractable cough associated with terminal lung cancer. Methadone is also used as part of the treatment of dependence on opioid drugs, although prolonged use of methadone itself may result in dependence. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1082-3)
Nalbuphine
A narcotic used as a pain medication. It appears to be an agonist at kappa opioid receptors and an antagonist or partial agonist at mu opioid receptors.
Buprenorphine
A derivative of the opioid alkaloid THEBAINE that is a more potent and longer lasting analgesic than MORPHINE. It appears to act as a partial agonist at mu and kappa opioid receptors and as an antagonist at delta receptors. The lack of delta-agonist activity has been suggested to account for the observation that buprenorphine tolerance may not develop with chronic use.
Nalorphine
A narcotic antagonist with some agonist properties. It is an antagonist at mu opioid receptors and an agonist at kappa opioid receptors. Given alone it produces a broad spectrum of unpleasant effects and it is considered to be clinically obsolete.
Levallorphan
An opioid antagonist with properties similar to those of NALOXONE; in addition it also possesses some agonist properties. It should be used cautiously; levallorphan reverses severe opioid-induced respiratory depression but may exacerbate respiratory depression such as that induced by alcohol or other non-opioid central depressants. (From Martindale, The Extra Pharmacopoeia, 30th ed, p683)
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