Trial Search Results

Opiate-Induced Tolerance & Hyperalgesia in Pain Patients

Opiates such as morphine are the cornerstone medications for the treatment of moderate to severe pain. Recent evidence suggests that pain patients on chronic opioid therapy become more sensitive to pain (hyperalgesia) over time. There is also a long-standing notion that analgesic tolerance to opioids (habituation) develops during chronic use even though this phenomenon has never been prospectively studied. Our specific aims propose to prospectively test the hypotheses that; 1) Pain patients on chronic opioid therapy develop dose-dependent tolerance and/or hyperalgesia to these medications over time, 2) Opioid-induced tolerance and hyperalgesia develop differently with respect to various types of pain, 3) Opioid-induced hyperalgesia occurs independently of withdrawal phenomena, and 4) Opioid-induced tolerance and hyperalgesia develop differently based on gender and/or ethnicity. This proposed study will be the first quantitative and prospective study of tolerance and hyperalgesia in pain patients and will have important implications for the rational use of opioids in the treatment of chronic pain.

Stanford is currently not accepting patients for this trial.

Lead Sponsor:

National Institute of General Medical Sciences (NIGMS)

Stanford Investigator(s):


  • Drug: Morphine
  • Drug: Placebo


Phase 4


Inclusion Criteria:

   - opioid na├»ve (or less than 4 vicodin equiv/day)

   - 18-70 years old

   - candidate for opioid therapy for nonmalignant pain.

Exclusion Criteria:

   - history of substance abuse or severe psychiatric disease

   - use of medications for the treatment of neuropathic pain as these may alter tolerance
   or hyperalgesia

   - neurological conditions interfering with experimental pain testing, e.g. severe
   peripheral neuropathy

Ages Eligible for Study

18 Years - 70 Years

Genders Eligible for Study


Not currently accepting new patients for this trial

Contact Information

Stanford University
School of Medicine
300 Pasteur Drive
Stanford, CA 94305
Lawrence Chu
Not Recruiting