Hyperalgesia in Methadone-Maintained Patients: Can it be Treated?
Condition: Opioid-Induced Hyperalgesia
MeSH terms: Hyperalgesia
Intervention: Gabapentin;; Placebo
Intervention description: Gabapentin titrated to daily dose of 2400mg PO over 1 week with established dose taken daily for 5 weeks.; Placebo titrated over 1 week with established dose taken daily for 5 weeks.
Intervention MeSH terms: Gabapentin
Phase: Phase 2
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Enrollment: 26.0
Sex: All
Minimum age: 21 Years
Maximum age: 55 Years
Healthy volunteers: No
Keywords: opioid-induced hyperalgesia; methadone; gabapentin; opioid addiction

Summary:

      Utilizing a double-blind, placebo-controlled design, the proposed work will evaluate the
      ability of an adjuvant anticonvulsant analgesic to diminish or reverse the opioid-induced
      hyperalgesia complicating the pain states suffered by Methadone-Maintained (MM) patients.
      Specifically, in a sample of MM patients, gabapentin, which has proven efficacy in treating
      neuropathic pain will be evaluated for its ability to ameliorate or diminish the
      opioid-induced hyperalgesia in these patients as reflected by changes on pain threshold and
      tolerance to both cold-pressor and electrical pain, at peak and through methadone blood
      levels. The results of this work will not only provide pharmacologic insight into the
      mechanisms underlying poor pain tolerance in this at-risk population, but also direction for
      the medical management of pain complicated by opioid-induced hyperalgesia.
    

Eligibility criteria:

        Inclusion Criteria:

        Potential participants must:

          1. Be between the ages of 21 and 55 years of age.

          2. DSM-IVR diagnosis of prescription opioid abuse or dependence disorder

          3. Be compliant in methadone treatment

          4. On a stable dose of methadone at least 6 weeks.

          5. Have provided random urine samples absent of any non-prescribed drugs of abuse x 2
             months

          6. Be in good physical health or in the case of a medical condition needing ongoing
             treatment, be in the care of a physician who is willing to take responsibility for
             such treatment. The same conditions apply in cases of patients with a psychiatric
             disorder needing ongoing treatment.

          7. Be agreeable to and capable of signing an informed consent.

        Exclusion Criteria:

        Potential participants must not:

          1. Have known sensitivity to gabapentin.

          2. Be substance dependent on alcohol, benzodiazepine, methamphetamine, cocaine or other
             drugs of abuse (except nicotine).

          3. Have any acute medical condition that would make participation medically hazardous,
             (e.g., acute hepatitis, unstable cardiovascular disease, liver or renal disease) or
             have liver enzyme values (AST or ALT) greater than 5 times normal range.

          4. Be acutely psychotic, severely depressed and in need of inpatient treatment, or an
             immediate suicide risk.

          5. Have a neurological or psychiatric illness (i.e., schizophrenia, Raynaud's disease,
             urticaria, stroke) that would affect pain responses.

          6. Be currently taking opioid analgesic medication for a painful condition on a regular
             basis.

          7. Be a nursing or pregnant female. Female of childbearing potential must agree to use a
             medically acceptable method of birth control, (e.g. oral contraceptives, barrier
             (diaphragm or condom) with or without spermicide, levonorgestrel implant,
             intra-uterine progesterone contraceptives system, medroxyprogesterone acetate
             contraceptive injection) or to complete abstinence. Females who become pregnant during
             the course of the study will be dropped from the study.

          8. Have a current or past history of high blood pressure, heart disease, stroke or
             currently have a pacemaker.