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1000 mg versus 650 mg Acetaminophen for Pain or Fever: A Review of the Clinical Efficacy

Last updated: June 17, 2016
Project Number: RC0786-000
Product Line: Rapid Response
Research Type: Drug
Report Type: Summary with Critical Appraisal
Result type: Report

Question

  1. What is the comparative clinical efficacy of 1000 mg acetaminophen compared with 600/650 mg acetaminophen for the treatment of pain?
  2. What is the comparative clinical efficacy of 1000 mg acetaminophen compared with 600/650 mg acetaminophen for managing fever?

Key Message

Acetaminophen 1000 mg single dose led to a higher percentage of people with at least 50% of pain relief over six hours, and a larger decrease in pain intensity, as compared to acetaminophen 650 mg in various acute post-operative pain conditions. Statistical significance of the differences in efficacy between the two doses was not reported in some studies. And in one study the number needed to treat to achieve benefit for one patient was not statistically different between doses. The risk of adverse events was similar between the two doses, and there were no serious adverse events reported with both doses. There was no evidence found on the comparative clinical efficacy of 1000 mg acetaminophen compared with 650 mg acetaminophen for the management of fever. Comparative studies on the recommended maximum daily dose and long term use of acetaminophen are needed.