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

Hospital de Clinicas de Porto Alegre

Status and phase: Completed; Phase 3; Phase 2

Conditions: Schizophrenia; Chronic Pain, Widespread; Acute Pain

Treatments: Drug: Placebo; Drug: Ketamine

Study type: Interventional

Funder types: Other

Identifiers

NCT03915938

15-0019

Details and patient eligibility

About

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

Full 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.

Enrollment: 24 patients

Sex: Male

Ages: 18 to 40 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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24 participants in 2 patient groups, including a placebo group

Group S-Ketamine

Experimental group

Description:

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.

Treatment:

Drug: Ketamine

Group Placebo

Placebo Comparator group

Description:

A previously prepared identical solution containing only normal saline will be infused at the same infusion rates of group ketamine.

Treatment:

Drug: Placebo