TCTR20180608001.

Study name	Comparing efficacy of loading and non‐loading colchicine in acute crystal induced arthritis
Methods	Randomised controlled trial
Participants	Inclusion criteria Participants aged 18 years or older Acute CPPD or gout arthritis within 48 hours, confirmed with synovial fluid examination or diagnosed by ACR/EULAR classification criteria for gout 2015 Never exposed to uric lowering agent, or use uric lowering agent in stable dose for at lease 30 days Prescribed colchicine 0.6 mg per day or less Prescribed prednisolone 5 mg per day or less Exclusion criteria Co‐exiting other causes of arthritis Participants who have contraindication to colchicine Participants who received analgesic or NSAIDs before included eGFR less than 30 by Cockcroft‐Gault equation Participants who cannot estimate pain score Participants who have significantly severe comorbidities
Interventions	Study arm 1: 2 tablets of colchicine (0.6 mg) taken orally at 0 hour and 1 tablet of colchicine (0.6 mg) taken orally at 1 hour Study arm 2: 1 tablet of colchicine (0.6 mg) taken orally at 0 hour
Outcomes	Primary outcome Pain score reduction measured on visual analogue scale (VAS) after 24 hours Secondary outcome Pain score reduction after 24 hours in participants with eGFR more than 60 and less than 60 Pain score reduction on VAS at 6, 12, and 48 hours Participants satisfaction at 48 hours on VAS Proportion of participants who have at least 50% pain score reduction (timeframe 24 and 48 hours) Adverse events (timeframe 24, 48 hours record) Sign of inflammation (timeframe 24 hours scaling score)
Starting date	Date of registration: 7 June 2018
Contact information	Ployrung Vechpanich 110 Intawarorod rd T.Sriphume A.Muang Chiang Mai 50200 Thailand Email: gemmyrainbow@hotmail.com
Notes	Estimated trial completion date: 31 January 2019 No source of funding reported

ACR/EULAR: American College of Rheumatology/European Alliance of Associations for Rheumatology
CPPD: calcium pyrophosphate dihydrate
eGFR: estimated glomerular filtration rate
VAS: visual analogue scale