Dextromethorphan, Gabapentin, and Oxycodone to Treat Opioid-Induced Hyperalgesia

Overview[ - collapse ][ - ]

Purpose Individuals who reduce or stop use of opioid medications are at risk for developing hyperalgesia, which is an increased sensitivity to pain. This study will compare the effectiveness of dextromethorphan, gabapentin, and oxycodone at reducing hyperalgesia in individuals addicted to opioids who are concurrently receiving methadone treatment.
ConditionHyperalgesia
Opioid-Related Disorders
InterventionDrug: Gabapentin
PhaseN/A
SponsorNational Institute on Drug Abuse (NIDA)
Responsible PartyNational Institute on Drug Abuse (NIDA)
ClinicalTrials.gov IdentifierNCT00218374
First ReceivedSeptember 16, 2005
Last UpdatedAugust 11, 2008
Last verifiedAugust 2008

Tracking Information[ + expand ][ + ]

First Received DateSeptember 16, 2005
Last Updated DateAugust 11, 2008
Start DateOctober 2006
Estimated Primary Completion DateNot Provided
Current Primary Outcome MeasuresPain response (measured after each pain testing session on Days 1, 4, 36, and 39) [Time Frame: 6 week] [Designated as safety issue: No]
Current Secondary Outcome MeasuresNot Provided

Descriptive Information[ + expand ][ + ]

Brief TitleDextromethorphan, Gabapentin, and Oxycodone to Treat Opioid-Induced Hyperalgesia
Official TitleHyperalgesia in Methadone Patients: Can it be Treated?
Brief Summary
Individuals who reduce or stop use of opioid medications are at risk for developing
hyperalgesia, which is an increased sensitivity to pain. This study will compare the
effectiveness of dextromethorphan, gabapentin, and oxycodone at reducing hyperalgesia in
individuals addicted to opioids who are concurrently receiving methadone treatment.
Detailed Description
Opioid medications are frequently used for the treatment of moderate to severe pain;
however, individuals who use opioids have a high risk of becoming addicted. Opioid users who
abruptly stop using opioid drugs may experience withdrawal symptoms, including drug craving,
sweating, sleep disruption, nausea, irritability, and pain. Hyperalgesia, a severe and
excessive sensitivity to pain, is a serious condition that may also occur when opioid use is
reduced or discontinued. Opioid medications affect both the pain inhibitory and facilitatory
systems, meaning that while they are effective at treating pain in many individuals, they
also have the ability to intensify pain and cause hyperalgesia in some opioid users. Three
medications, dextromethorphan, gabapentin, and oxycodone, may alleviate the symptoms of
hyperalgesia and lessen an individual's sensitivity to pain. Further research is needed to
confirm the benefits of these medications for opioid addicts. The purpose of this study is
to compare the effectiveness of dextromethorphan, gabapentin, and oxycodone at reducing
opioid-induced hyperalgesia in methadone-maintained opioid addicts.

This study will involve three separate experiments. Participants in Experiment 1 will be
randomly assigned to receive either dextromethorphan or placebo; in Experiment 2,
participants will be randomly assigned to receive either gabapentin or placebo; and in
Experiment 3, participants will be randomly assigned to receive either oxycodone or placebo.
Each experiment will last 5 weeks. All 3 experiments will begin with a screening session.
Potential participants will undergo a physical exam and an electrocardiogram. Blood and
urine will be collected for laboratory tests and drug screening. Each individual's medical
and drug history will be reviewed and psychological and opiate withdrawal symptoms will be
assessed. Individuals who complete the screening and meet all study requirements will be
permitted to continue in the study.

All participants will be maintained on methadone throughout the study. Participants will
also receive either the study medication (dextromethorphan, gabapentin, or oxycodone) or
placebo four times per day beginning on Day 5. Study visits will take place once a week. At
each visit, medications for the previous week will be accounted for and medications for the
following week will be dispensed. Questionnaires and self-reports will be completed to
assess depression levels and drug use. Urine tests will be used to screen for the presence
of drugs and alcohol. During the study, participants will take part in four pain testing
sessions to measure pain threshold and tolerance; two sessions will take place during Week 1
and another two sessions will occur during Week 5. The pain testing sessions will include a
cold pressor (CP) test and an electrical stimulation (ES) procedure. The CP test will
involve placing an arm in ice water for a short period of time; the ES procedure will
involve stimulating muscle nerve endings via electrodes placed on the skin. Immediately
after the CP and ES sessions, blood will be drawn for laboratory testing. Participants will
again complete questionnaires and self-reports, and urine samples will be collected. Gift
cards will be offered as an incentive for attending study visits and having negative drug
tests.
Study TypeInterventional
Study PhaseN/A
Study DesignAllocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator), Primary Purpose: Treatment
Condition
  • Hyperalgesia
  • Opioid-Related Disorders
InterventionDrug: Gabapentin
Gabapentin initiated up to a daily dose of 2400mg PO x 5 weeks
Study Arm (s)Not Provided

Recruitment Information[ + expand ][ + ]

Recruitment StatusActive, not recruiting
Estimated Enrollment60
Estimated Completion DateNot Provided
Estimated Primary Completion DateJune 2007
Eligibility Criteria
Inclusion Criteria:

- Be between the ages of 18 and 55 years of age.

- Meets DSM-IV diagnostic criteria for opioid dependence

- Taking a stable dose of methadone for 6 weeks prior to study entry and is compliant
in methadone maintenance treatment

- Is in good physical health or under a physician's care if a medical condition
requires ongoing treatment

Exclusion Criteria:

- Known sensitivity to dextromethorphan, gabapentin, or oxycodone

- Currently dependent on alcohol, benzodiazepine, or any drug (other than nicotine)

- Currently in an acutely psychotic, severely depressed state and in need of inpatient
treatment

- Immediate suicide risk

- Neurological or psychiatric illness (e.g., peripheral neuropathy, schizophrenia,
neuropathic pain, Raynaud's disease, or urticaria)

- Acute medical condition that would make study participation medically dangerous
(e.g., acute hepatitis, unstable cardiovascular disease, liver disease, or kidney
disease)

- Liver enzyme values five times greater than normal

- Currently taking analgesic medication for a painful condition on a regular basis

- Current or past history of high blood pressure, heart disease, or stroke

- Currently using a pacemaker

- Pregnant or breastfeeding
GenderBoth
Ages18 Years
Accepts Healthy VolunteersNo
ContactsNot Provided
Location CountriesUnited States

Administrative Information[ + expand ][ + ]

NCT Number NCT00218374
Other Study ID NumbersNIDA-15463-1
Has Data Monitoring CommitteeNot Provided
Information Provided ByNational Institute on Drug Abuse (NIDA)
Study SponsorNational Institute on Drug Abuse (NIDA)
CollaboratorsNot Provided
Investigators Principal Investigator: Margaret Compton, PhD University of California, Los Angeles
Verification DateAugust 2008

Locations[ + expand ][ + ]

University of California, Los Angeles
Los Angeles, California, United States, 90024