Diphenhydramine and Sweating

Phase 4

Completed

• Conditions: Sweating; Diphenhydramine Causing Adverse Effects in Therapeutic Use; Allergic Rhinitis; Hyperthermia
• Interventions: Drug: Placebo; Drug: Diphenhydramine

• Registration Number: NCT05586477
• Lead Sponsor: Lakehead University

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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2022-10-14
• Study First Submitted QC: 2022-10-17
• Study First Posted: 2022-10-19
• Study Start: 2022-11-21
• Primary Completion: 2023-06-23
• Study Completion: 2023-06-23
• Status Verified: 2023-09
• Last Update Submitted: 2023-09-11
• Last Update Posted: 2023-09-13

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• 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

Exclusion Criteria

• 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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Intervention Order (Diphenhydramine -Placebo)	Placebo	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
Intervention Order (Placebo - Diphenhydramine)	Placebo	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
Intervention Order (Placebo - Diphenhydramine)	Diphenhydramine	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
Intervention Order (Diphenhydramine -Placebo)	Diphenhydramine	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

Primary Outcome Measures

Name	Time	Method
Whole body sweat loss	Measured during both placebo and diphenhydramine intervention trials trials, separated by no more than 28 days	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.

Secondary Outcome Measures

Name	Time	Method
Change in rectal temperature	Measured during both placebo and diphenhydramine intervention trials trials, separated by no more than 28 days	Change in rectal temperature from pre- to post- exercise using a pediatric grade thermistor

Trial Locations

Locations (1)

Lakehead Unviersity; 🇨🇦 Thunder Bay, Ontario, Canada