None listed
Conditions
Brief summary
We wish to investigate the effect of two different types of thermal stimuli on the responses (spontaneous pain, flare, allodynia and hyperalgesia) to intradermal capsaicin in healthy male volunteers.
Interventions
Intradermal capsaicin (100 micrograms) will be administered intradermally into the dominant forearm once on both study day 1 and study day 2. Intradermal capsaicin is not being used as an intervention (e.g. treatment), but instead as a method to produce neuropathic like pain symptoms in healthy pain-free volunteers. Sensitivity to two different types of thermal test will be performed in the presence of intradermal capsaicin. One thermal test involves placing a small match boxed sized thermode on
Intradermal capsaicin (100 micrograms) will be administered intradermally into the dominant forearm once on both study day 1 and study day 2. Intradermal capsaicin is not being used as an intervention (e.g. treatment), but instead as a method to produce neuropathic like pain symptoms in healthy pain-free volunteers. Sensitivity to two different types of thermal test will be performed in the presence of intradermal capsaicin. One thermal test involves placing a small match boxed sized thermode on participants dominant forearm for 30 seconds. Once the thermode is removed from participants dominant forearm, participants will then be asked to rate how painful the thermode was, an area of flare will be measured and participants sensitivity to von Frey hairs and a foam paintbrush will be measured. The other thermal test involves participants placing their dominant forearm onto specialised temperature bars for 30 seconds. Once participants are asked to remove their dominant forearm from the specialised temperature bars, participants will then be asked to rate how painful the speciliased temperature bars were, an area of flare will be measured and participants sensitivity to von Frey hairs and a foam paintbrush will be measured. Both thermal tests are performed at non-harmful temperatures. As the study is being conducted as a 2-way cross over design, participants will randomly be assigned to either the thermode test or the specialised temperature bars test for study visit 1 or study visit 2. Therefore, if a participant is assigned to the thermode test for study visit 1, they will be assigned to the speciliased temperature bars test for study visit 2. Thermal tests will be performed prior to intradermal capsaicin and at 5, 15, 30, 45, 60 and 90 minutes post intradermal capsaicin. Each study day will be approximately 2 hours and 45 minutes long.
Sponsors
Professor Paul Rolan
Eligibility
Sex/Gender
Male
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
A participant will be eligible for inclusion in this study only if all of the following criteria apply: 1.Male 2.Right handed 3.Aged between 18-65 years inclusive 4.In good general health without clinically significant renal, hepatic, cardiac or other disease, as determined by the Principal Investigator 5.Agree to and be capable of signing the Informed Consent Form
Exclusion criteria
A participant will be excluded from the study if any of the following criteria apply: 1.Significant scarring on the planned site of investigation 2.Tattoos on the planned site of investigation 3.Suffering from an active inflammatory process (e.g. acute pain, influenza, active infection, rheumatoid arthritis etc.) 4.Have had a clinically significant infection in the 4 weeks prior to study day 1 5.Suffering form an impaired immune response, e.g. HIV/AIDS sufferers, Hep B or C sufferers, organ transplant recipients or known current history of malignancy. Significance is to be determined by the investigator 6.Taking immunosuppressant drugs e.g. azathioprine, methotrexate, cyclosporine 7.Dark skin colouration that precludes flare assessment 8.Positive urine drug screen for presence of non-prescribed drugs of abuse 9.Positive breath alcohol concentration prior to study day 1 and 2 10.Recent use of opioids (e.g. morphine use within 1 week, or codeine use (<30 mg) within last 5 days) 11.Use of anxiolytics, anti-depressants and anti-epileptic medications within the previous 4 weeks 12.Clinically significant abnormalities in blood tests conducted during screening, as determined by the Principal Investigator 13.Sensory deficits at the planned quantitative sensory testing (QST) site resulting from medical conditions, such as diabetes; alcohol neuropathy; severe thyroid, liver or kidney diseases 14.Suffering from a clinically diagnosed major psychiatric disorder, such as major depression; bipolar disorder; schizophrenia; anxiety disorder and psychosis 15.History of excessive use of alcohol, defined as more than 28 units of alcohol per week 16.Known disorder of thermal pain sensitivity (e.g. Raynaud’s Phenomenon) 17.Inability to tolerate study procedures at screening familiarisation session 18.Current or history of a chronic pain condition 19.Frequent migraines, as determined by the Principal Investigator
Outcome results
None listed