A Randomised, Placebo-Controlled, Crossover Trial of Acetaminophen in Cancer Patients on Strong Opioids
To assess whether regular oral acetaminophen can reduce pain in cancer patients already on a
strong opioid regimen.
It is estimated that 75% of people with advanced cancer suffer significant pain. Many of
these people continue to have pain despite being on strong opioids. The rationale behind
adding an additional analgesic with a different mechanism of action is to attempt to improve
analgesia without increasing side effects.
This is a double blind, randomised placebo-controlled, crossover trial to evaluate whether
the addition of regular acetaminophen can reduce pain in cancer patients already on a strong
opioid regimen. The study will be performed in ambulatory cancer patients who have pain
that is believed to be caused by their cancer, and who have already been stabilised on an
opioid regimen of > 60mg/day of morphine equivalents. Each patient will be randomly
allocated to receive either acetaminophen 1g qid or an identical appearing placebo qid for a
seven-day period, and then crossed over to the other arm for a further seven-day period.
Patients will complete daily pain diaries and weekly questionnaires (Brief Pain Inventory)
and comparison will be made between the pain scores for the two treatment periods. Patient
preference for the two treatment periods will also be evaluated.
A randomised, double-blind, placebo controlled crossover trial to determine if the addition
of regular acetaminophen (1g PO qid) leads to improved analgesic control in adult cancer
patients at Princess Margaret Hospital, who are already on strong opioids (> 60mg morphine
equivalents/day) as evaluated by daily pain scores measured by Numerical Rating Scales (NRS)
and the Brief Pain Inventory (BPI).
Regular acetaminophen improves pain control in cancer patients who are already on strong
Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Treatment
Patient preference for the acetaminophen or the placebo arm as assessed by asking the patient whether he/she preferred treatment period 1 or treatment period 2
Post completion of period 2
Janette Vardy, MD
University Health Network, University of Toronto
Canada: Health Canada