Inflammatory Responses to Acute and Chronic Opioid Exposure in Humans

Not Applicable

Terminated

Brief Summary: We aim to examine the extent to which inflammation is affected by acute and chronic opioid exposure.

Detailed Description: We are interested in learning how the immune system and the inflammation process is effected by acute and chronic opioid exposure. Preliminary evidence in animal models show that acute opioid exposure leads to decreased inflammatory responses, while chronic opioid exposure causes increased inflammatory responses, as measured by local cytokine release at the site of injury. Translating these findings to humans will lead to important new mechanistic knowledge that may ultimately improve our ability to treat pain.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

Patients younger than 18 or older than 70
Patients unwilling or unable to follow study instructions
Patients who don't speak English
Patients who are taking prescription opioid medications (e.g. vicodin, percocet) or are unwilling to refrain from taking anti-inflammatory medications such as Advil or Naproxen during 2 weeks prior to and during the 1 month study

Arm && Interventions

Group	Intervention	Description
Chronic Opioid Exposure	Morphine Sulfate	15mg sustained release morphine sulfate, with a maximum dose of 120mg. Patients will be titrated up to a maximum dose of 8 pills a day for one month.
Acute Opioid Exposure	Morphine Sulfate	15mg sustained release morphine sulfate, with a maximum dose of 120mg. Patients will be titrated up to a maximum dose of 8 pills a day for one month.

Primary Outcome Measures

Name	Time	Method
Changes in Cytokine Release	Changes in cytokine release are compared between blood samples drawn on Day 1 and Day 30	5 CCs of blood are drawn on day 1 and day 30.

Secondary Outcome Measures

Name	Time	Method
Peltier Device-Heat Pain	Differences in heat pain are assessed between measurements taken on Day 1 and Day 30	A hand-held 0.6x0.6 inch metal probe will be brought into contact with the patient's skin. Starting at 95 F, the probe temperature will increase at a rate of 1.8 F per second. The patient will be asked to push a button of a hand-held device as soon as the patient feels pain.
Mechanical Pain Stimuli	Changes in mechanical pain stimuli will be assessed between measurements taken on Day 1 and Day 30	Pain sensitivity will be tested with three different mechanical stimuli that can elicit mild pain: * Stroking stimulus: skin will be tested with a brush that is moved three times across the lesion * Punctuated stimulus: a metal rod (1/100 of an inch in diameter) mounted onto 10 different weights (0.03-2.9 ounces) will repetitively be placed onto the skin * Blunt stimulus: a flat probe (0.4 inch in diameter) will be placed five times onto the patient's skin
Laser Doppler Images	Changes in laser doppler images are measured between images taken on Day 1 and Day 30	The laser doppler is a noninvasive, painless measurement of superficial perfusion that reflects inflammation. Laser doppler images will be taken once per study visit.