HONOLULU, HI — Acetaminophen1,000mg does provide an incremental benefit vs. acetaminophen 650mg, reportedDaniel Qi, from McNeil Consumer Healthcare, Fort Washington, PA, at theAmerican Pain Society’s 31st Annual Scientific Meeting.
Dr.Qi and his colleagues utilized the Dental Impaction Pain Model to evaluate thedose-response relationship of acetaminophen 1,000mg vs. 650mg over 6 hours. Thisrandomized, double-blind, parallel-group, placebo-controlled study enrolled 540patients (52% female, aged 16–50 years, 95% Caucasian) who required surgicalremoval of impacted third molars. Patients were given a single dose ofacetaminophen 1,000mg, acetaminophen 650mg, or placebo when moderate or greaterpain and a Visual Analog Scale (VAS) score >50 out of 100mm wasreported within four hours following surgery. Patients were encouraged to waitat least 90 minutes prior to rescuing.
Painintensity and pain relief were measured over six hours at 15, 30, 45, 60, 75, and 90 minutes, and at2, 3, 4, 5, and 6 hours (VAS 0–100mm) to assess the primary efficacy endpointof the weighted Sum of Pain Intensity Difference (SPID) and Total Pain Relief(TOTPAR) scores over six hours (SPID6). Acetaminophen 1,000mg showed a 24%improvement in VAS score compared to 650mg (529.4 vs. 427.3; P=0.001). Acetaminophen 1,000mg was alsosignificantly superior to 650mg in the following categories: SPID6 (P=0.001), TOTPAR6 (P=0.002),Time to Rescue Analgesic (P<0.001), rescue rates through four hours (20% vs. 32%; P=0.002)) and six hours (29% vs. 46%; P<0.001). The Subject GlobalEvaluation also showed more “very good” or “excellent” ratings for theacetaminophen 1,000mg than the 650mg (49% vs. 35%; P=0.001).
Comparedto placebo, both dosages of acetaminophen were significantly superior (P<0.001) in achieving the efficacyendpoints. Both active treatment groups demonstrated similar stopwatch Times toConfirmed First Perceptible and Meaningful Relief. Adverse events were reportedby 18.5% of subjects, with no clinically important difference among the threetreatment groups. No serious adverse events were reported and no subjectsdiscontinued due to an adverse event.
In response to therecent FDA Advisory Committee Meeting questioning the benefit of the two strengthsof acetaminophen, Dr. Qi stated, “This study provides definitive evidence of apositive and clinically relevant dose-response between acetaminophen 650mg andacetaminophen 1,000mg.”