Characterization of Pain Processing Mechanisms in Irritable Bowel Syndrome

• Status: Completed
• Trial end date: 2006-03-01
• Target enrollment: 0
• Participant gender: All

Summary

This study is being done to collect new information on irritable bowel syndrome, a disease that causes abdominal pain that does get better with treatment or keeps coming back ("chronic"). To better understand what causes the irritable bowel syndrome, we are studying drugs used to treat pain, dextromethorphan, naloxone, fentanyl, and lidocaine. We will study the effects these drugs have on experimental pain.

Dextromethorphan is used in non-prescription cough syrups. Naloxone is used for reversing the effects of narcotic pain relievers. Fentanyl is a narcotic used to treat pain and to make a person relaxed (sedated) before anesthesia. The purpose of this study is to see what kinds of pain are affected by these drugs in persons who have irritable bowel syndrome and persons who do not have this problem.

• Phase: Phase 2
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: US Department of Veterans Affairs; VA Office of Research and Development
• Treatments: Dextromethorphan; Fentanyl; Lidocaine; Naloxone

Criteria

Inclusion Criteria:

• Premenopausal women age 18 years or older OR healthy controls

• Patients with diarrhea predominant IBS that meet the *Rome II criteria

• The subject must speak English and be able to give informed consent

• All subjects will be tested in the follicular stage of the menstrual cycle as determined by menstrual history and urine testing

• Functional Bowel Disorder Severity Index score of none (0 points) for controls and moderate (37-110 points) for IBS patients

• Normal baseline EKG

Exclusion Criteria:

• Subject is currently participating in another research protocol that could interfere or influence the outcome measures of the present study

• Subject is unable to give informed consent

• A medical condition that would contraindicate the use of lidocaine (i.e., amide allergy) or a previous history of an abnormal EKG

• Subjects with a positive pregnancy test will be excluded because the use of lidocaine is contraindicated in pregnant women

• Subject is currently taking pain medications, NSAIDs, antihistaminics, antidepressants (tricyclic antidepressants [TCA]/selective serotonin reuptake inhibitors [SSRI]), anti-convulsants, migraine medications, and cough suppressants

• Presence of systemic disease: diabetes, thyroid disease, gastrointestinal/liver disease (other than IBS), collagen vascular disease, focal or systemic neurological disease, malignancy, seropositive for HIV, or documented psychiatric disorders

• Presence of any chronic pain condition including fibromyalgia

• Subject drinks > 2 oz. alcohol/day on a regular basis

• Presence of large, palpable hemorrhoids on digital rectal exam that may alter rectal lidocaine adherence to rectal wall

• Abnormal baseline EKG