Topical Acetaminophen for Itch Relief: a Proof of Concept Study in Healthy Subjects

NCT03997851 | Completed Phase 1 Results FDA Drug

• 1 other identifier: 20190133
• Study Type: interventional
• Target: 17
• Locations: 1 country
• Sites: 1

Brief Summary

Currently, topical antihistamines and corticosteroids are mainly used for itching relief. However, the over the counter antihistamines are not effective on all itch conditions. Acetaminophen is a popular and widely used OTC drug for pain relief. Although its mode of action is still unknown, recent studies have shown that acetaminophen indirectly activates cannabinoid CB1 receptors. Recent studies have shown that topical cannabinoid agonists are effective for itch relief, the efficacy of topical acetaminophen will be tested for non-histaminergic itch relief.

Conditions

Pruritus

Outcome Measures

Primary Outcomes (2)

• Peak Itch Intensity Between the Vehicle and Active Treatments During Non-histaminergic Itch Induction

  Peak itch intensity between the vehicle and 3 other active treatments (5%, 2.5%, and 1% acetaminophen gels) after non-histaminergic itch induction (cowhage). Itch intensity was measured on a 10cm scale visual analog scale for 10 minutes. 0 was weighted with "no itch" and 10 was weighted with "most itch imaginable".

  10 minutes

• Peak Itch Intensity Between the Vehicle and Active Treatments During Histaminergic Itch Induction

  Peak itch intensity between the vehicle and 3 other active treatments (5%, 2.5%, and 1% acetaminophen gels) after histaminergic itch induction. Itch intensity was measured on a 10cm scale visual analog scale for 10 minutes. 0 was weighted with "no itch" and 10 was weighted with "most itch imaginable".

  10 minutes

Secondary Outcomes (1)

• Thermal Threshold Detection (Heat Pain)

  3 minutes

Study Arms (4)

Topical 5% acetaminophen gel

EXPERIMENTAL

Topical 5% acetaminophen gel will be applied to one 4x4 cm predefined skin area on the ventral forearm during 2 study visits. The gel will be applied to the test area and will be allowed 30 minutes to adsorb. Following this pre-treatment, residual gel will be removed and itch induction/sensory testing will commence, strictly within the pre-treated area.

Drug: Acetaminophen

Topical 2.5% acetaminophen gel

EXPERIMENTAL

Topical 2.5% acetaminophen gel will be applied to one 4x4 cm predefined skin area on the ventral forearm during 2 study visits. The gel will be applied to the test area and will be allowed 30 minutes to adsorb. Following this pre-treatment, residual gel will be removed and itch induction/sensory testing will commence, strictly within the pre-treated area.

Drug: Acetaminophen

Topical 1% acetaminophen gel

EXPERIMENTAL

Topical 1% acetaminophen gel will be applied to one 4x4 cm predefined skin area on the ventral forearm during 2 study visits. The gel will be applied to the test area and will be allowed 30 minutes to adsorb. Following this pre-treatment, residual gel will be removed and itch induction/sensory testing will commence, strictly within the pre-treated area.

Drug: Acetaminophen

Topical vehicle gel

PLACEBO COMPARATOR

Topical vehile gel will be applied to one 4x4 cm predefined skin area on the ventral forearm during 2 study visits. The gel will be applied to the test area and will be allowed 30 minutes to adsorb. Following this pre-treatment, residual gel will be removed and itch induction/sensory testing will commence, strictly within the pre-treated area.

Drug: Carbomer 980

Interventions

Acetaminophen DRUG

Topical acetaminophen gel

Also known as: Topical acetaminophen gel

Topical 1% acetaminophen gel; Topical 2.5% acetaminophen gel; Topical 5% acetaminophen gel

Carbomer 980 DRUG

Topical vehicle gel

Also known as: Topical vehicle gel

Topical vehicle gel

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy subjects must be between 18 and 50 years of age.
• Must be in general good health with no disease or physical conditions that would impair evaluation of itch and pain perception.
• No history of chronic itch or pain.
• Must abstain from the use of any systemic or topical anti-histamine, steroid, or pain relief medications from the week prior to the study till the completion of the study.
• Must abstain from the use of moisturizers on the arms 24 hours before study visits.

You may not qualify if:

• Individuals under 18 or over 50 years of age.
• Inability to complete the required measures.
• The presence of an itchy skin disease.
• Diagnosis of diseased that would affect itch or pain perception (e.g. neuropathies).
• Currently enrolled in any investigational study in which the subject is receiving any type of drug, biological, or non-drug therapy.
• Use of oral, topical analgesics, or other medications known to interfere with itch or pain perception in the week prior to the study and throughout the study (e.g. antihistamines, anesthetics, opioids, neuroleptics, etc.).
• Use of emollients on the arms a week prior to the study and throughout the study.
• Known allergies to acetaminophen and cowhage.
• Pregnant women. (Women of child bearing potential will undergo an hCG pregnancy test).
• Currently incarcerated.

Sponsors & Collaborators

• University of Miami: lead

Study Sites (1)

University of Miami

Miami, Florida, 33136, United States

Location

MeSH Terms

Conditions

Pruritus

Interventions

Acetaminophen; carbomer

Condition Hierarchy (Ancestors)

Skin Diseases; Skin and Connective Tissue Diseases; Skin Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Acetanilides; Anilides; Amides; Organic Chemicals; Aniline Compounds; Amines

Results Point of Contact

• Title: Leigh Nattkemper
• Organization: University of Miami

Lxn202@med.miami.edu

3055889734

Study Officials

• Gil Yosipovitch, MD

  University of Miami

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: The antipruritic effect of 3 topical treatments of varying doses and 1 vehicle treatment will be explored in each subject. One study visit will consist of testing all topical formulations on histaminergic induced itch, and second study visit will test all topical formulations on non-histaminergic induced itch.

Study Record Dates

• First Submitted: June 24, 2019
• First Posted: June 25, 2019
• Study Start: July 22, 2019
• Primary Completion: March 18, 2020
• Study Completion: March 18, 2020
• Last Updated: December 8, 2025
• Results First Posted: April 19, 2021

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)