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Trial registered on ANZCTR


Registration number
ACTRN12622001123730
Ethics application status
Approved
Date submitted
6/08/2022
Date registered
16/08/2022
Date last updated
8/06/2023
Date data sharing statement initially provided
16/08/2022
Date results information initially provided
8/06/2023
Type of registration
Prospectively registered

Titles & IDs
Public title
Finding a better nasal anaesthetic: the efficacy of tetracaine and oxymetazoline as a topical nasal anaesthetic and decongestant
Scientific title
The efficacy of tetracaine and oxymetazoline as a topical nasal anaesthetic and decongestant in healthy participants
Secondary ID [1] 307720 0
Nil known
Universal Trial Number (UTN)
U1111-1281-3247
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Nasal endoscopy 327285 0
Condition category
Condition code
Anaesthesiology 324418 324418 0 0
Anaesthetics

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Tetracaine 0.5% + oxymetazoline 0.05% spray (1 mg tetracaine, 0.1 mg oxymetazoline)
Tetracaine 1% + oxymetazoline 0.05% spray (2 mg tetracaine, 0.1 mg oxymetazoline)
Tetracaine 2% + oxymetazoline 0.05% spray (4 mg tetracaine, 0.1 mg oxymetazoline)

0.2 mL of each preparation will be given intranasally as a spray, as a single exposure. The absolute doses of each drug for this volume of each preparation are given above.

Participants will be randomised to receive one of these sprays or cophenylcaine (control) in each nasal cavity. This will be given by an investigator (either a specialist or advanced trainee in Otolaryngology Head and Neck Surgery) in two sittings at least one day apart so that each participant will receive all four sprays in a random order in a consistent, reproducible manner.
Intervention code [1] 324195 0
Treatment: Drugs
Comparator / control treatment
Cophenylcaine (5% lignocaine + 0.5% phenylephrine) nasal spray

0.2 mL of this preparation will be given intranasally as a spray, as a single exposure. The absolute doses of the drugs given are therefore 10 mg lignocaine and 1 mg phenylephrine.
Control group
Active

Outcomes
Primary outcome [1] 332229 0
Time to onset of anaesthesia. This will be measured using a series of Semmes-Weinstein monofilaments. An initial measurement will be made prior to application of the anaesthetic spray by measuring sensory threshold at the head of the inferior turbinate. Measurements will then be taken every 30 s for 2 min, then every minute until 20 min, until sensory threshold increases. The time point at which this occurs will be recorded.
Timepoint [1] 332229 0
30 s to 20 min following application of the sprays
Primary outcome [2] 332281 0
Time to peak anaesthesia. This will be measured using a series of Semmes-Weinstein monofilaments. Measurements will be taken at the head of the inferior turbinate every 30 s for 2 min, then every minute until 20 min after the spray is applied, until sensory threshold stops increasing. The time point at which this occurs will be recorded.
Timepoint [2] 332281 0
30 s to 20 min following application of the sprays
Primary outcome [3] 332282 0
Degree of anaesthesia. This will be measured using a series of Semmes-Weinstein monofilaments. Measurements will be taken at the head of the inferior turbinate every 30 s for 2 min, then every minute until 20 min after the spray is applied, until sensory threshold stops increasing. This sensory threshold will be recorded.
Timepoint [3] 332282 0
30 s to 20 min following application of the sprays
Secondary outcome [1] 412634 0
Time to offset of anaesthesia (this is a primary outcome). This will be measured using a series of Semmes-Weinstein monofilaments. Measurements will be taken at the head of the inferior turbinate every 30 s for 2 min, then every minute until 20 min, then every 10 min until 1 hour after the spray is applied, until sensory threshold returns to normal. The time point at which this occurs will be noted.
Timepoint [1] 412634 0
30 s to 1 hour following application of the sprays

Eligibility
Key inclusion criteria
Able and willing to provide informed consent to participate
Minimum age
18 Years
Maximum age
75 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Unable to provide informed consent, or non-consenting
Known hypersensitivity to constituents of the test solutions
Pregnancy
Acute unwellness
Smoking
Sinonasal or systemic disease affecting the sinonasal mucosa
- Granulomatous disease
- Vasculitis
- Cystic Fibrosis
- Ciliary dysmotility
- Immune deficiency
- Rhinosinusitis

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The nasal sprays will be randomised to left or right nasal cavities by an investigator not involved in recruitment or treatment and the bottles will be marked as "left" or "right" with all other markings on the bottles obscured.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a random number generator
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
Intervention assignment
Crossover
Other design features
Ten healthy volunteers will be recruited. 0.2mL of each spray will be given intranasally (one preparation randomised to each nasal cavity over two sittings at least one day apart, with participants serving as their own controls). The time to onset of anaesthesia, time to peak anaesthesia, degree of anaesthesia and time to offset will be recorded.
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Power analyses were conducted using R v4.1.1 “Kick Things” (R Core Team, Vienna, Austria).

Following a conservative estimate of 10 mm difference in mean peak sensory thresholds between the two anaesthetics based on a previous study comparing tetracaine with lignocaine and a standard deviation of the difference of 5 mm, 6 participants would be required to identify a significant difference between groups using a paired t-test (alpha = 0.05, 1 - beta = 0.95). However, this study used 2% lignocaine, a lower concentration than that in cophenylcaine, which may have increased the difference they detected between tetracaine and lignocaine. To our knowledge, no previous studies exist comparing different concentrations of tetracaine in this setting on which power calculations could be based. For this reason, we will recruit 10 patients to allow for detection of a potential smaller difference between cophenylcaine and tetracaine than that in the previous study, as well as potential smaller differences between the three tetracaine preparations.

Statistical analyses will be performed with the assistance of a statistician using a standard statistical software package. Demographics will be summarised using descriptive measures. Interventions will be compared using appropriate statistical tests following analysis for normality of distribution of the data.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
5/09/2022
Actual
14/03/2023
Date of last participant enrolment
Anticipated
31/03/2023
Actual
30/03/2023
Date of last data collection
Anticipated
31/03/2023
Actual
31/03/2023
Sample size
Target
10
Accrual to date
Final
10
Recruitment outside Australia
Country [1] 24933 0
New Zealand
State/province [1] 24933 0
Auckland

Funding & Sponsors
Funding source category [1] 311993 0
Charities/Societies/Foundations
Name [1] 311993 0
The Garnett Passe and Rodney Williams Memorial Foundation
Country [1] 311993 0
Australia
Primary sponsor type
University
Name
University of Auckland
Address
Private Bag 92019
Auckland 1142
New Zealand
Country
New Zealand
Secondary sponsor category [1] 313486 0
None
Name [1] 313486 0
Address [1] 313486 0
Country [1] 313486 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 311414 0
Northern A Health and Disability Ethics Committee
Ethics committee address [1] 311414 0
Ministry of Health
133 Molesworth Street
PO Box 5013
Wellington 6011
New Zealand
Ethics committee country [1] 311414 0
New Zealand
Date submitted for ethics approval [1] 311414 0
02/03/2022
Approval date [1] 311414 0
13/07/2022
Ethics approval number [1] 311414 0
2022 FULL 11767

Summary
Brief summary
Cophenylcaine (a combination of lignocaine and phenylephrine, a local anaesthetic and decongestant respectively) is commonly used as a spray to make the inside of the nose numb in Otolaryngology (ear, nose and throat surgery) clinics. However, other local anaesthetics like tetracaine are more potent than lignocaine, and phenylephrine tastes very bitter whereas other decongestants like oxymetazoline are essentially tasteless.

Our hypothesis is that a tetracaine/oxymetazoline spray will act more quickly and give better anaesthesia to the inside of the nose than cophenylcaine.

We will test cophenylcaine and three different concentrations of tetracaine/oxymetazoline in ten healthy participants. We will give them two sprays of one anaesthetic/decongestant in one nostril, and two sprays of another anaesthetic/decongestant in the other nostril, and measure the sensation of the lining of the nose at regular intervals using fine hair-like filaments designed for this purpose. Then, we will do the same thing with the other two anaesthetic/decongestants at least one day later, so that all participants will receive all four anaesthetic/decongestants. This will show clearly whether tetracaine/oxymetazoline gives better nasal anaesthesia than cophenylcaine, and if so, which concentration of tetracaine is best for this purpose.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 121014 0
Prof Richard Douglas
Address 121014 0
University of Auckland
Faculty of Medical and Health Sciences
Building 507
20-33 Park Avenue
Grafton, 1023
Auckland
Country 121014 0
New Zealand
Phone 121014 0
+64 9 923 9820
Fax 121014 0
Email 121014 0
richard.douglas@auckland.ac.nz
Contact person for public queries
Name 121015 0
Dr Sam Hale
Address 121015 0
University of Auckland
Faculty of Medical and Health Sciences
Building 507
20-33 Park Avenue
Grafton, 1023
Auckland
Country 121015 0
New Zealand
Phone 121015 0
+64 9 9239820
Fax 121015 0
Email 121015 0
sam.hale@auckland.ac.nz
Contact person for scientific queries
Name 121016 0
Dr Sam Hale
Address 121016 0
University of Auckland
Faculty of Medical and Health Sciences
Building 507
20-33 Park Avenue
Grafton, 1023
Auckland
Country 121016 0
New Zealand
Phone 121016 0
+64 9 9239820
Fax 121016 0
Email 121016 0
sam.hale@auckland.ac.nz

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.