Diphenhydramine and Sweating

NCT05586477 | Completed Phase 4

• 2 other identifiers: 2022509265937
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

In 2012, it was estimated that nearly 1 in 4 Canadians suffer from allergic rhinitis. To add, 78% of individuals working in predisposing environments are predicted to develop occupational rhinitis. Currently, the most popular treatment for rhinitis is antihistamine medication such as diphenhydramine, a first-generation antihistamine sold commercially as Benadryl®. Due it its anticholinergic effects, diphenhydramine has been suggested to impair the whole body sweating response during heat stress, potentially leaving consumers at an increased risk of heat-related illness. This randomized control trial approved by Health Canada will investigate whether ingesting extra strength diphenhydramine (50mg) will alter whole-body sweat losses during 60 minutes of exercise.

Conditions

Diphenhydramine Causing Adverse Effects in Therapeutic Use; Hyperthermia; Allergic Rhinitis; Sweating

Keywords

thermoregulation; diphenhydramine; anticholinergic; sweating

Outcome Measures

Primary Outcomes (1)

• Whole body sweat loss

  Change in body mass from pre- to post-exercise corrected for respiratory and metabolic water losses using a digital platform scale accurate to +/- 2 grams.

  Measured during both placebo and diphenhydramine intervention trials trials, separated by no more than 28 days

Secondary Outcomes (1)

• Change in rectal temperature

  Measured during both placebo and diphenhydramine intervention trials trials, separated by no more than 28 days

Study Arms (2)

Intervention Order (Placebo - Diphenhydramine)

OTHER

On separate days, participants will march on a treadmill for 60 minutes at a fixed rate of oxygen consumption (\~1.75 liters of oxygen consumption per minute) in \~28°C and 30% relative humidity

Drug: Placebo; Drug: Diphenhydramine

Intervention Order (Diphenhydramine -Placebo)

OTHER

On separate days, participants will march on a treadmill for 60 minutes at a fixed rate of oxygen consumption (\~1.75 liters of oxygen consumption per minute) in \~28°C and 30% relative humidity

Drug: Placebo; Drug: Diphenhydramine

Interventions

Placebo DRUG

A placebo pill (i.e., sugar) will be consumed 2 h before intervention.

Intervention Order (Diphenhydramine -Placebo); Intervention Order (Placebo - Diphenhydramine)

Diphenhydramine DRUG

Extra strength Benadryl (DIN 02470144) will be consumed 2 h before intervention

Intervention Order (Diphenhydramine -Placebo); Intervention Order (Placebo - Diphenhydramine)

Eligibility Criteria

• Age: 18 Years - 49 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Able to safely perform \~60 minutes of moderate intensity exercise
• No known hypersensitivity to diphenhydramine
• Not on any prescribed medication
• Body-mass index (BMI) less than 30

You may not qualify if:

• Outside 18 - 49 years of age
• Diagnosed with any cardiovascular, respiratory, neurological or metabolic disease
• History of any cardiovascular, respiratory, neurological or metabolic disease
• Unable to exercise for 60 minutes at moderate intensity, or have a musculoskeletal injury
• BMI \> or = 30

Sponsors & Collaborators

• Lakehead University: lead

Study Sites (1)

Lakehead Unviersity

Thunder Bay, Ontario, P7B 5E1, Canada

Location

Related Publications (1)

• Newhouse D, Mihalcin E, Lefebvre K, Nucci M, Ravanelli N. Thermal and Cardiovascular Responses during Exertional Heat Stress after Diphenhydramine Use: A Randomized Crossover Trial. Med Sci Sports Exerc. 2024 Dec 1;56(12):2328-2337. doi: 10.1249/MSS.0000000000003527. Epub 2024 Jul 31.

  PMID: 39140777 DERIVED

MeSH Terms

Conditions

Hyperthermia; Rhinitis, Allergic

Interventions

Diphenhydramine

Condition Hierarchy (Ancestors)

Body Temperature Changes; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Heat Stress Disorders; Wounds and Injuries; Rhinitis; Nose Diseases; Respiratory Tract Diseases; Respiratory Hypersensitivity; Otorhinolaryngologic Diseases; Hypersensitivity, Immediate; Hypersensitivity; Immune System Diseases

Intervention Hierarchy (Ancestors)

Ethylamines; Amines; Organic Chemicals; Benzhydryl Compounds; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Hydrocarbons

Study Officials

• Nicholas Ravanelli, PhD

  Lakehead University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: Double-blind
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: October 14, 2022
• First Posted: October 19, 2022
• Study Start: November 21, 2022
• Primary Completion: June 23, 2023
• Study Completion: June 23, 2023
• Last Updated: September 13, 2023

Record last verified: 2023-09

Locations

CA (1)