Neurotropin to Treat Chronic Neuropathic Pain
Condition: Complex Regional Pain Syndrome Type I; Complex Regional Pain Syndrome Type II
MeSH terms: Neuralgia; Complex Regional Pain Syndromes; Reflex Sympathetic Dystrophy; Causalgia; Syndrome; Somatoform Disorders
Intervention: Placebo; Neurotropin
Intervention description: 4 tabs b.i.d.; 4 tabs b.i.d.
Intervention MeSH terms: Neurotropin
Phase: Phase 2
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 21.0
Sex: All
Minimum age: 18 Years
Healthy volunteers: No
Keywords: Analgesia; Causalgia; CRPS; Neuropathic Pain; Oral Surgery; Reflex Sympathetic Dystrophy; Sympathetic Nervous System; Chronic Regional Pain Syndrome

Summary:

      This study will examine the effectiveness of the drug neurotropin in treating chronic pain
      after injury to a limb or a large nerve.

      Two groups of patients will participate in this study: patients with complex regional pain
      syndrome type 1, or CRPS-I (also called reflex sympathetic dystrophy) and patients with
      complex regional pain syndrome type 2, or CRPS-II. CRPS-I is pain that develops after
      relatively minor injury to an arm or leg, but lasts much longer and is much more severe than
      would normally be expected. CRPS-II is pain resulting from injury to a large nerve.
      Candidates will have a history and physical examination, blood tests, and electrocardiogram.
      Participants will undergo the following tests and procedures:

      Patients with CRPS I and II will receive an individualized regimen of physical therapy and
      standard treatment to control their pain. In addition, they will receive neurotropin or
      placebo tablets for 5 weeks, then no trial medicine for at least 1 week, and then the other
      trial drug for the next 5 weeks. That is, patients who took placebo the first 5 weeks will
      take neurotropin the second 5 weeks and vice versa. Neither the patients nor the doctors will
      know who received which drug during the two intervals until the study is over. Patients will
      complete questionnaires about their pain, quality of life, and ability to perform daily
      living activities. They will have various tests to measure pain (such as sensitivity to heat
      and cold, to an electric current, to a mild pin prick, etc.); to provide information about
      changes in their condition (such as tests of range of motion of joints and limb size); to
      measure blood circulation and sweating in the arm or leg (such as measurements of blood flow
      to the limb, skin temperature, and sweat production), and other procedures.
    

Eligibility criteria:

        -  INCLUSION CRITERIA:

        CRPS patients are referred with a diagnosis of CRPS-I or CRPS-II in one limb only, based on
        pain (1) that is post-traumatic and spread beyond the region of the injury; (2) has
        persisted for more than 2 weeks; and (3) is associated with swelling, altered skin color or
        skin temperature, altered sweating, allodynia or hyperesthesia or limitation of active
        movement. Atrophic changes in skin, hair loss or nail changes, or disuse atrophy of
        skeletal muscle may be present.

        Both sexes are to be studied.

        All ethnic and racial groups can participate.

        Patients must be willing to return to NIH for follow-up evaluation under this protocol.

        EXCLUSION CRITERIA:

        Pregnant and lactating women are excluded.

        Based on the oral surgeon's postoperative diagnosis, any extraction which is classified as
        producing unusual surgical trauma will result in exclusion from the remainder of the study.

        Dental subjects will also be excluded if they are not adequately sedated by midazolam alone
        and require intraoperative administration of an opioid drug such as fentanyl,
        administration of greater than 14.4 ml of local anesthetic (2% lidocaine with 1:100,000
        epinephrine), or postoperative administration of a steroid for possible injury to the
        inferior alveolar nerve.

        Patients referred with CRPS-I or CRPS II who have abnormal screening test results or who
        have non-traumatic disorders to which pain may be attributed (gout, malignancy, arthritis,
        etc.) will be excluded.

        Any patients who have had ablative procedures for treatment of their neuropathic pain
        disorder will not be eligible for inclusion in this study.

        Patients who have a positive HIV result will be excluded.

        Subjects with obviously impaired mental capacity that precludes informed consent and
        ability to provide adequate self-ratings are to be excluded.