Ketamine's Effect Changes the Cortical Electrophysiological Activity Related to Semantic Affective Dimension of Pain

Phase 2

Completed

• Conditions: Acute Pain; Chronic Pain, Widespread; Schizophrenia
• Interventions: Drug: Placebo; Drug: Ketamine

• Registration Number: NCT03915938
• Lead Sponsor: Hospital de Clinicas de Porto Alegre

Brief Summary

This is a clinical trial that intend to determine the effects of S-ketamine on event-related potentials associated with semantic affective pain-processing

Detailed Description

Ketamine is a unique anesthetic with neural effects that are distinct from more commonly-used γ-aminobutyric acid agonists. Evidence suggest that analgesic effect of ketamine is primarily related to the affective than the sensorial aspects of pain interpretation. The investigators investigated whether ketamine, a noncompetitive NMDA antagonist, would modify the perceived emotional valence of pain-related words when compared to non-pain-related ones in healthy volunteers. Using a single session double-blind parallel placebo-controlled design, 24 healthy volunteers were randomized to receive intravenous S-ketamine (n=12) or placebo (n=12). During infusion (plasmatic target of 60 ng/ml), the effects of ketamine were recorded using EEG and oddball behavioral data was monitored. Evoked potentials (N200 and P300 components) were recorded during performance of a semantic written word oddball task containing pain-related (targets) and non-pain-related words (standards). Expected results: The findings of this study can help in the understanding of neurophysiologic mechanisms involved in ketamine's effects both in psychiatric diseases as in the treatment of postoperative acute and chronic pain.

Study Timeline

• Study Start: 2017-01-02
• Primary Completion: 2017-11-30
• Study Completion: 2017-11-30
• Status Verified: 2018-01
• Study First Submitted: 2019-04-12
• Study First Submitted QC: 2019-04-15
• Last Update Submitted: 2019-04-15
• Study First Posted: 2019-04-16
• Last Update Posted: 2019-04-16

Recruitment & Eligibility

• Status: COMPLETED
• Sex: Male
• Target Recruitment: 24

Inclusion Criteria

• male healthy subjects with higher education level

Exclusion Criteria

• do not understand Portuguese language
• obese patients (BMI > 27 kg/m2)
• use of NSAID, steroids, analgesics, anticonvulsant drugs, as well as alpha and beta-blockers
• score ≥ 13 on Beck II Questionnaire
• sleep deprivation in the night before evaluation

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Group Placebo	Placebo	A previously prepared identical solution containing only normal saline will be infused at the same infusion rates of group ketamine.
Group S-Ketamine	Ketamine	S-Ketamine will be diluted in normal saline and administrated in a target controlled infusion using an infusion pump to obtain a plasma target of 60 ng/ml according to Domino's model. Infusion will start during the interval between the 3rd and 4th blocks of the task.

Primary Outcome Measures

Name	Time	Method
AUC of the grand averaged mean differences between ERPs elicited by target and non-target words	up to 60 min	EEG will be recorded during all task time. The main outcome will be the area under de curve (AUC) of the grand averaged mean differences between event-related potencials (ERPs) elicited by target and non-target words at 100-200, 300-500 and 800-900 ms after stimulus presentation for parietal electrophysiological signal (Pz). The ERPs represent the averaged voltage of several trials.

Secondary Outcome Measures

Name	Time	Method
Word ratings related to the semantic valence	up to 60 min	After viewing each word, volunteers were asked to classify them according to the semantic valence in the following categories: "positive," "negative" or "neutral."
Response times (behavioural oddball data)	up to 60 min	Response times to word classification in oddball task