Acetaminophen analgesia in children: placebo effect and pain resolution after tonsillectomy

Abstract

High dose acetaminophen (100 mg/kg) was no more effective than 40 mg/kg and was associated with increased nausea and vomiting. A target effect compartment concentration of 10 mg/l is expected to produce a pain reduction of 2.6 units. The placebo model accounted for a maximum pain reduction of 5.6 units at 3 h. The combination of placebo effect and preoperative acetaminophen 40 mg/kg results in pain scores below 4 units for 5 h postoperatively.

Pharmacokinetics/Pharmacodynamics of Acetaminophen Analgesia in Japanese Patients with Chronic Pain

“…10,24) In those studies, the delayed onset of the effects is described by a one-compartment with an effect compartment model. The equilibration half-times as an index of the delayed onset of the effect are 1.3, 10) 0.88 24) h. The equilibration half-time in this study was 0.53 h. Pickering et al reported that the analgesic effect of APAP involves a central serotonergic mechanism, including an indirect interaction of APAP with serotonergic receptors. 25) The delayed onset of the effect and the counterclockwise hysteresis relationship might be due to this pharmacologic mechanism.…”

Pain Assessment and Management

“…Antipyretic plasma levels are 10-20 mg/l, levels required for analgesia are thought to be similar, and so most dosing regimens aim to maintain trough plasma concentrations of 10 mg/l [ 61 ]. A greater initial dose followed by maintenance doses not exceeding recommended maximum daily doses is generally recommended.…”

Safety of opioid patch initiation in Australian residential aged care

“…There is some evidence for analgesic efficacy at this concentration in children (Anderson et al, 2001 Level III-3) but a relationship between plasma concentration and analgesia…”