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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
The effects of minocycline on breathing during sleep in patients prescribed opioid drugs for chronic pain.
Scientific title
A Phase IIa trial of patients on opioids for chronic pain, testing the efficacy of minocycline as a glial attenuator versus placebo on respiratory depression and analgesia.
Secondary ID [1] 282069 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Central sleep apnoea 288558 0
chronic pain 288559 0
Condition category
Condition code
Respiratory 288888 288888 0 0
Sleep apnoea
Anaesthesiology 288889 288889 0 0
Pain management

Study type
Description of intervention(s) / exposure
Minocycline hydrochloride, 100 mg will be administered orally, twice daily for 3 days.

A washout period of at least 1 week will follow.

The study is randomised so the washout is between placebo then minocycline, or minocycline then placebo. the study is double-blinded, so only the statistician in this study will know.
Intervention code [1] 286668 0
Treatment: Drugs
Comparator / control treatment
Placebo will be taken in the same frequency and duration as the intervention treatment.

Minocycline will be "over-encapsulated" with a slightly larger capsule also used for placebos so they'll look identical and should taste (swallowed whole and probably minimal) the same
Control group

Primary outcome [1] 289018 0
% of patients with central apnoea index <5 /hr
Timepoint [1] 289018 0
3 days after starting administration of minocycline
Secondary outcome [1] 301574 0
analgesia effectiveness scored by Brief Pain Inventory (BPI)
Timepoint [1] 301574 0
3 days after starting administration of minocycline
Secondary outcome [2] 301575 0
CO2 respiratory control sensitivity during wake, using pseudorandom binary stimulation test
Timepoint [2] 301575 0
3 days after starting administration of minocycline

Key inclusion criteria
- Age 18-65 years.
- On prescribed oral long acting opioids within pre-specified dose ranges (morphine 40 – 500 mg /day, oxycodone 30 – 350mg/day or methadone 20 – 100 mg/day) .
- Central sleep apnoea index greater or equal to 5 /hr.
Chronic pain patients will only be included if they are prescribed and taking the opioid medication mentioned above, so chronic pain by itself will not be an inclusion.
Minimum age
18 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
- Clinically significant respiratory (e.g. COPD), cardiovascular (e.g. congestive cardiac failure, previous cerebro-vascular accident) or metabolic disorders.
- Major psychiatric illness.
- History of substance abuse.
- Contra-indications to minocycline use, ie. Known allergies to tetracycline, severe renal insufficiency, systemic lupus erythematosus, pregnancy or breastfeeding, concurrent prescription and non-prescription medications, vitamins, nutritional supplements, or herbal products with known interactions with tetracylines (e.g. Vitamin A/retinoids).
- Marked daytime sleepiness Epworth Sleepiness Scale (ESS) equal to or greater than 15.
- Morbid obesity BMI equal to or greater than 35 kg/m2.
- Concurrent central sleep apnoea treatment and unwilling or unable to come off treatment for in-laboratory study nights.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
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
The people analysing the results/data
Intervention assignment
Other design features
Phase 2
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 6975 0
5041 - Daw Park

Funding & Sponsors
Funding source category [1] 286844 0
Name [1] 286844 0
The Repat Foundation
Address [1] 286844 0
Daws Road, Daw Park, SA, 5041, Australia
Country [1] 286844 0
Primary sponsor type
Repatriation General Hospital
Daws Road, Daw Park, SA, 5041, Australia
Secondary sponsor category [1] 285636 0
Other Collaborative groups
Name [1] 285636 0
Australian Institute for Sleep Health
Address [1] 285636 0
Daws Road, Daw Park, SA, 5041, Australia
Country [1] 285636 0

Ethics approval
Ethics application status
Ethics committee name [1] 288909 0
Southern Adelaide Clinical Human Research Ethics Committee
Ethics committee address [1] 288909 0
Flinders Dr Bedford Park SA 5042
Ethics committee country [1] 288909 0
Date submitted for ethics approval [1] 288909 0
Approval date [1] 288909 0
Ethics approval number [1] 288909 0

Brief summary
The purpose of this study is to find a new way of treating central sleep apnoea and drug tolerance caused by opioid medication prescribed for chronic pain. The medication tested in this study is Minocycline, a commonly used antibiotic with effects on the central nervous system's immune system.

Minocycline will reduce the severity of central sleep apnoea in patients prescribed opioids for chronic pain.

Minocycline will increase the analgesic efficacy of opioids prescribed to chronic pain patients.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 38302 0
A/Prof Peter Catcheside
Address 38302 0
Adelaide Institute for Sleep Health
Daws Rd, Daw Park, 5041
South Australia
Country 38302 0
Phone 38302 0
+64 (08) 8275 1309
Fax 38302 0
Email 38302 0
Contact person for public queries
Name 38303 0
Mr Michael Mogford
Address 38303 0
Adelaide Institute for Sleep Health
Daws Rd, Daw Park, 5041
South Australia
Country 38303 0
Phone 38303 0
+64 468 962 749
Fax 38303 0
Email 38303 0
Contact person for scientific queries
Name 38304 0
Mr Michael Mogford
Address 38304 0
Adelaide Institute for Sleep Health
Daws Rd, Daw Park, 5041
South Australia
Country 38304 0
Phone 38304 0
+64 468 962 749
Fax 38304 0
Email 38304 0

No information has been provided regarding IPD availability
Summary results
No Results