Study: NCT04115462

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Morphine
Description: A 20 mg tablet of morphine

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: Placebo oral tablet
Description: Matching tablet of placebo

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Histamine
Description: 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.

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: Histamine
Description: 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.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Cowhage (Mucuna Pruriens)
Description: 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

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: Cowhage (Mucuna Pruriens)
Description: 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

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: isotonic saline
Description: 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.

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: isotonic saline
Description: 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.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Histamine
Description: 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.

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: Histamine
Description: 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.

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Cowhage (Mucuna Pruriens)
Description: 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

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: Cowhage (Mucuna Pruriens)
Description: 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