Table 1.

Paracetamol rescue medication in randomised controlled osteoarthritis trials in selected recent publications.

Trial	Doses allowed (mg)	Primary or secondary endpoint	Results	Remarks
Frestedt et al. [20]	325 mg per tablet with 1-2 tablets to be taken every 4–6 hours as needed for pain	No	No significant differences between the two groups for rescue medication consumption at any single time point or over time	No figures given
Karlsson et al. [21]	≤4000 mg/day could be taken as for unacceptable pain for more than 24 hours	No	Rescue medication usage was significantly better than under placebo	No figures given
Jacquet et al. [22]	Tablets equivalent to 500 mg paracetamol alone or combined with weak opiates (e.g., coproxamol or coparein)	Main outcome measure 500 mg paracetamol equivalent tablets per week (PET/week) measured each month	Single-component Paracetamol (number of users, tablets/week ± SD) Phytalgic 12 (21 ± 14.7) Placebo 15 (15.4 ± 10.4)	Add-on study to the usual symptomatic medication (analgesics and/or NSAIDs)
Krüger et al. [23]	500 mg tablets; intake was permitted if necessary due to pain but not 48 hours before visits	Secondary endpoint, recorded daily by the patient in the diary and checked by the physician at each visit (pill counting)	Low acetaminophen consumption; differences between the groups not significant	No figures given
Puopolo et al. [24]	For breakthrough pain, if needed; no dose reported	Secondary endpoint; use was determined by tablet counts	Patients treated with etoricoxib or ibuprofen used significantly less paracetamol than those receiving placebo for breakthrough pain Paracetamol use in the etoricoxib and ibuprofen groups was similar	Figures not listed in the table of the key secondary results
Reginster et al. [25]	325 mg tablets; use was restricted (it was not permitted during the initial 2 weeks of treatment) and recorded	No	No data shown
Sawitzke et al. [26]	Up to 4 g daily could be taken, but patients were instructed not to take this drug within 24 h of a follow-up visit to allow for accurate measurement of their current pain levels	No	The use of paracetamol averaged 570 mg daily. The lowest use was in the celecoxib (465 mg) group and the highest use in the placebo group (645 mg)	Rank order of rescue drug use (least to greatest) exactly paralleled to that of the primary efficacy outcome
Schnitzer et al. [27]	500 mg tablets for use in case of increased OA pain, with a maximum accepted dose of 2000 mg/day	Additional efficacy measures	Average daily tablets use in the placebo group 1.77 versus 1.33 to 1.43 in the naproxcinod groups and 1.34 in the naproxen group
Yang et al. [28]	Maximum of 4 g/day	No	No data shown	Asked to stop analgesics at least 1 week before completing the questionnaires and visiting their treating orthopaedic surgeon
Thorne et al. [29]	325 mg to 650 mg every 4 h to 6 h as required	Secondary end point; compared for each treatment, based on the average daily consumption, and was summarized each week	Significantly greater use during the placebo phase (3.4 ± 3.6 tablets/day) than during the CR tramadol phase (2.4 ± 3.1 tablets/day)