PACE--the first placebo controlled trial of paracetamol for acute low back pain: design of a randomised controlled trial.
BACKGROUND
Clinical practice guidelines recommend that the initial treatment of acute low back pain (LBP) should consist of advice to stay active and regular simple analgesics such as paracetamol 4 g daily. Despite this recommendation in all international LBP guidelines there are no placebo controlled trials assessing the efficacy of paracetamol for LBP at any dose or dose regimen. This study aims to determine whether 4 g of paracetamol daily (in divided doses) results in a more rapid recovery from acute LBP than placebo. A secondary aim is to determine if ingesting paracetamol in a time-contingent manner is more effective than paracetamol taken when required (PRN) for recovery from acute LBP.


METHODS
The study is a randomised double dummy placebo controlled trial. 1650 care seeking people with significant acute LBP will be recruited. All participants will receive advice to stay active and will be randomised to 1 of 3 treatment groups: time-contingent paracetamol dose regimen (plus placebo PRN paracetamol), PRN paracetamol (plus placebo time-contingent paracetamol) or a double placebo study arm. The primary outcome will be time (days) to recovery from pain recorded in a daily pain diary. Other outcomes will be pain intensity, disability, function, global perceived effect and sleep quality, captured at baseline and at weeks 1, 2, 4 and 12 by an assessor blind to treatment allocation. An economic analysis will be conducted to determine the cost-effectiveness of treatment from the health sector and societal perspectives.


CONCLUSIONS
The successful completion of the trial will provide the first high quality evidence on the effectiveness of the use of paracetamol, a guideline endorsed treatment for acute LBP.
Williams
Christopher M
CM
The George Institute for International Health, University of Sydney, PO Box M201 Missenden Rd, Camperdown, NSW 2040, Australia. cwilliams@george.org.au
Latimer
Jane
J
Maher
Christopher G
CG
McLachlan
Andrew J
AJ
Cooper
Chris W
CW
Hancock
Mark J
MJ
Day
Richard O
RO
McAuley
James H
JH
Lin
Chung-Wei Christine
CW
D000082:Acetaminophen / Q000008:administration & dosage* / Q000009:adverse effects / Q000191:economics; D000203:Activities of Daily Living / Q000523:psychology; D000208:Acute Disease; D000698:Analgesia / Q000191:economics / Q000379:methods*; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage* / Q000009:adverse effects / Q000191:economics; D002985:Clinical Protocols / Q000592:standards; D003362:Cost-Benefit Analysis; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D006801:Humans; D017116:Low Back Pain / Q000188:drug therapy* / Q000191:economics / Q000523:psychology; D017063:Outcome Assessment, Health Care / Q000191:economics / Q000379:methods; D010147:Pain Measurement / Q000191:economics / Q000379:methods; D015990:Placebo Effect; D010919:Placebos
D018712:Analgesics, Non-Narcotic; D010919:Placebos; D000082:Acetaminophen