A Relation of Morphine-induced Itch and Pain Processing

Summary

In This experiment, the investigators would like to test the two following hypotheses regarding the mechanisms by which opioids cause itch:

1. Opioids cause itch by a spinal disinhibition mechanism (central nervous system (CNS) effect).
2. Opioids cause itch through a mast cell-destabilizing effect leading to release of histamine and tryptase in the skin where itch is evoked (peripheral mechanism).

Conditions

• Morphine
• Itch

Interventions

DRUG

Morphine

A 20 mg tablet of morphine

DRUG

Placebo oral tablet

Matching tablet of placebo

DRUG

Histamine

Histaminergic itch will be evoked by a 1% histamine solution. A droplet of histamine solution will be placed on the predetermined area on the forearm, and the SPT lancet will be pierced through the histamine with 120 g of pressure for 1-2 seconds.

DRUG

Cowhage (Mucuna Pruriens)

25 spicules will be inserted in the centre of the predefined skin area on the forearm. The spicules will be gently rubbed for 15-20 seconds in circular motion to facilitate epidermal penetration

DRUG

isotonic saline

A droplet of saline (0.9%) as vehicle control will be placed on the predetermined area on the forearm and the lancet will be pierced through the droplet.

DRUG

Histamine

Histaminergic itch will be evoked by a 1% histamine solution. A droplet of histamine solution will be placed on the predetermined area on the mandibular area, and the SPT lancet will be pierced through the histamine with 120 g of pressure for 1-2 seconds.

DRUG

Cowhage (Mucuna Pruriens)

25 spicules will be inserted in the centre of the predefined skin area on the mandibular area. The spicules will be gently rubbed for 15-20 seconds in circular motion to facilitate epidermal penetration

Sponsors & Collaborators

• Aalborg University

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

20 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2020-01-15

Primary Completion

2020-05-01

Completion

2020-07-07

Countries

• Denmark

Study Locations