Clinical trial NCT06245564: Effect of Ketamine, Amitriptyline and Their Combination on Itch
Official title: Effect of Ketamine, Amitriptyline and Their Combination on Histaminergic and Non-histaminergic Itch
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Itch
Lead sponsor: Aalborg University
Sponsor class: OTHER
First posted: 2024-02-07
Enrollment: 30
Sex: ALL
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: In each participant, the four different creams will be applied in a randomized position. After the cream removal, itch will be induced using histamine in one session and cowhage in the other session.
Primary purpose: BASIC_SCIENCE

Brief summary: Chronic itch affects approximately a fifth of the global population and is associated with substantial negative consequences for the affected individuals. Furthermore, there is a lack of efficient treat-ment options for chronic itch. Topical ketamine cream has been used successfully to relieve various forms of pain, and we hypothesize that topical ketamine relieves itch through a mechanism of action comparable to that in pain relief.

The aim of this project is to evaluate the effects of ketamine both alone and in combination with amitriptyline on histaminergic and non-histaminergic itch induced by histamine and cowhage, respectively.

Detailed description: The main action of ketamine, 2-(2-chlorophenyl)-2-(methylamino)-cyclohexanone, is to antagonize the glutamate N-methyl-D-aspartate (NMDA) receptors. In the clinical setting, topical ketamine cream has been used successfully to relieve various pathogenic forms of pain. In addition to its pain-relieving effects, the cream was also reported to have itch-relieving properties in a very limited study. However, its efficacy on itch has not been established, and the mechanism of action remains uncertain. Ketamine cream is used not only by itself, but also in conjunction with other analgesics. One of these is amitriptyline, which may enhance the analgesic effects of ketamine. The aim of this human experimental study is to use the well-characterized anesthetic Ketamine, both alone and in combination with amitriptyline, as a tool to modulate different histaminergic and non-histaminergic itch modalities evoked by histamine and cowhage.

Eligibility criteria: Inclusion Criteria:

* Healthy men and women
* 18-60 years
* Speak and understand English

Exclusion Criteria:

* Pregnancy or lactation
* Drug addiction defined as any use of cannabis, opioids, or other drugs
* Previous or current history of neurological, dermatological, immunological, musculoskeletal, cardiac disorder or mental illnesses (psychiatric diagnosis) that may affect the results (e.g., neuropathy, muscular pain in the upper extremities, anxiety, depression, schizophrenia etc.)
* Moles, wounds, scars, or tattoos in the area to be treated or tested
* Current use of medications that may affect the trial such as antihistamines and pain killers.
* Participants had known allergy/discomfort to ketamine or amitriptyline
* Skin diseases
* Consumption of alcohol or painkillers 24 hours before the study days and between these
* Acute or chronic pain and itch
* Participation in other trials within 1 week of study entry (4 weeks in the case of pharmaceutical studies)
* Lack of ability to cooperate

Primary outcomes:
measure: Measuring itch by computerized Visual Analog Scale Scoring
timeFrame: Immediately after the intervention
measure: Measuring pain by computerized Visual Analog Scale Scoring
timeFrame: Immediately after the intervention
Secondary outcomes:
measure: Superficial blood perfusion
timeFrame: Immediately after the intervention
measure: Touch Pleasantness
timeFrame: Immediately after the intervention
measure: Mechanically evoked itch (MEI), intensity approach
timeFrame: Immediately after the intervention
measure: Mechanically evoked itch, spatial approach
timeFrame: Immediately after the intervention
measure: Mechanical Pain Thresholds (MPT)
timeFrame: Immediately after the intervention
measure: Mechanical Pain Sensitivity (MPS), intensity approach
timeFrame: Immediately after the intervention
measure: Mechanical Pain Sensitivity (MPS), spatial approach
timeFrame: Immediately after the intervention
measure: Cold Detection Thresholds (CDT)
timeFrame: Immediately after the intervention
measure: Warm Detection Thresholds (WDT)
timeFrame: Immediately after the intervention
measure: Cold Pain Thresholds (CPT)
timeFrame: Immediately after the intervention
measure: Heat Pain Thresholds (HPT)
timeFrame: Immediately after the intervention
measure: Pain to Supra-threshold Heat Stimuli (STHS)
timeFrame: Immediately after the intervention
Other outcomes:
Locations:
city: Gistrup
country: Denmark
facility: Center for Neuroplasticity and Pain Faculty of Medicine, Aalborg University
state: Aalborg
Study officials:
References: