Opiate-Induced Tolerance & Hyperalgesia in Pain Patients

National Institute of General Medical Sciences (NIGMS)

Status and phase

Completed

Phase 4

Conditions

Chronic Low Back Pain

Opioid-induced Hyperalgesia

Treatments

Drug: Morphine

Drug: Placebo

Study type

Interventional

Funder types

NIH

Identifiers

NCT00246532

5K23GM071400-02 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

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.

Enrollment

139 patients

Sex

All

Ages

18 to 70 years old

Volunteers

No Healthy Volunteers

Inclusion criteria

opioid naïve (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