The melatonin analgesic effect in a human pain model

• Register: REBEC
• Last refreshed on: 27 May 2013
• Main ID: RBR-7m3mnd
• Date of registration: 31/03/2012
• Primary sponsor: Hospital de Clínicas de Porto Alegre - Porto Alegre, RS, Brazil
• Public title: The melatonin analgesic effect in a human pain model
• Scientific title: The melatonin analgesic effect in a human nociceptive and inflammatory pain model.
• Date of first enrolment: 01/05/2011
• Target sample size: 60
• Recruitment status: recruitment completed
• URL: http://www.ensaiosclinicos.gov.br/rg/RBR-7m3mnd/
• Study type: Intervention
• Study design: Randomized, pararel, double-blind, 4 arms, phase 2,clinical trial.

Countries of recruitment

Brazil

Contacts

• Name: Luciana Stefani
• Affiliation: Hospital de Clínicas de Porto Alegre

• Name: Luciana Stefani
• Affiliation: Hospital de Clínicas de Porto Alegre

Key inclusion & exclusion criteria

Inclusion criteria: Healthy volunteers;
Age between 18 and 45 years;
Exclusion criteria: Current acute or chronic pain conditions;
Pregnancy;
Use of analgesics within 1 week;
Use of any psychoative medications;
Any chronic cardiac, rheumatologic, pulmonary, infectious or neurologic disease.

Age minimum: 18
Age maximum: 45Y
Gender: -

Health Condition(s) or Problem(s) studied

Acute pain
C10.597.617

Intervention(s)

In this study we'll have 4 groups of healthy volunteers (15 per group) that will be submitted to the intervention after basal pain tests (warm and heat pain threshold, heat pain tolerance and pressure pain threshold).
Intervention groups:
1)sublingual melatonin 0.05mg/kg,
2)sublingual melatonin 0.15 mg /kg
3)sublingual melatonin 0.25 mg/kg
4) placebo
The heat and pain thresholds will be determined by the method of limits, using a 30mm diameter thermodo applied in the non dominant aspect of the volar forearm. Baseline temperature was always set at 30.0ºC, and ramp rate was fixed at 1ºC/s, to a maximum at 52 ºC. Warm and heat pain thresholds will be accessed by the average of three consecutive stimuli, and the maximum temperature tolerated will be accessed once. The participant will be asked to press as quickly as possible a button at the moment the stimulation became warm (warm threshold) or painful (pain threshold). The pressure pain threshold and tolerance will be additionally measured on the tibial surface by pressure algometry.
Two separate sessions will be done, one before the intervention (basal values) and the other thirty minutes after the intervention.

Primary Outcome(s)

Increase in heat pain thresholds in a human pain model in healthy volunteers, using quantitative sensorial test. It is expected a decrease in pain in melatonin groups in a dose dependent way.

Increase in pressure pain threshold in healthy volunteers measured by pressure algometer. IIt is expected a decrease in pain in melatonin groups in a dose dependent way.

Increase in pressure pain threshold in healthy volunteers measured by pressure algometer. It is expected that melatonin use will reduce pain in a dose-dependent way.

Increase in thermal pain tolerance in human pain model in volunteers using the quantitative sensorial test. It is expected a decrease in pain in melatonin groups in a dose dependent way.

Secondary Outcome(s)

Increase sedation levels measured by visual analogue scale. It is expected that the melatonin use increase the sedation levels in a dose-dependent way.

Secondary ID(s)

CAAE 0432.0.001.000-07

Source(s) of Monetary Support

CNPQ - Brazil

FAPERGS - Brazil

Fundo de Incentivo à Pesquisa e Eventos- FIPE - Brazil

Secondary Sponsor(s)

Hospital de Clínicas de Porto Alegre - Porto Alegre, RS, Brazil