◊ BACKGROUND:
We have evaluated whether co-administration of intravenous (i.v.) paracetamol could enhance the analgesic efficacy of ketoprofen (a non-steroidal anti-inflammatory drug or NSAID) in patients undergoing a tonsillectomy.
◊ METHODS:
This prospective, randomized, double-blinded and placebo-controlled add-on study with three parallel groups included 114 patients, aged 16-50 years, and scheduled for elective tonsillectomy. All patients were given ketoprofen 1mg/kg i.v. after surgery, followed 5min later by paracetamol 1 or 2g i.v., or normal saline as a placebo. The primary outcome measure was the proportion of patients requiring oxycodone for rescue analgesia over the first 6h (pain score >30/100mm at rest or >50/100mm during swallowing) after surgery.
◊ RESULTS:
No difference was detected in the proportion of patients receiving oxycodone (31/37 in the paracetamol 1g group, 29/39 in the paracetamol 2g group and 30/38 in the ketoprofen-alone group) between the three groups. However, significantly less doses of rescue analgesia were provided in the paracetamol groups than in the ketoprofen-alone group (P=0.005); among those who required rescue analgesia, 27% less oxycodone was required in the paracetamol 1g group (80 doses, P=0.023) and 38% less in the paracetamol 2g group (64 doses, P=0.002) than in the ketoprofen-alone group (106 doses).
◊ CONCLUSIONS:
Combining paracetamol i.v. with ketoprofen at the end of tonsillectomy did not reduce the proportion of the patients requiring rescue analgesia, but the number of opioid doses was less in the add-on groups.
◊ Reviewed by F. Bonnet
Service d'Anesthésie-Réanimation,
Hôpital Tenon, Paris, France
Paracetamol is a non-opioid analgesic used to treat mild to moderate pain. The dose of paracetamol administered in adult postoperative patients is commonly 1 g every 6 hours. This dose achieves a decrease in morphine demand of less than 10 mg per 24 hours, which is not sufficient to significantly diminish opioid side effects. Paracetamol is commonly combined with non-steroidal anti-inflammatory drugs (NSAID) but the combination has inconsistently been reported of being superior to the administration of NSAIDs alone. Since the analgesic effect of paracetamol is dose-related, a few studies have used 2 g as initial dose in adults to improve analgesia.
Salonen et al. designed a study to assess the efficacy of the combination of ketoprofen and paracetamol in a dose-related manner. After tonsillectomy, patients were allocated to one of three groups. All groups received one dose of ketoprofen immediately after surgery and simultaneously either placebo or paracetamol at doses of 1 or 2 g. Endpoints were pain intensity and use of opioid rescue medication (oxycodone). Pain relief assessed on VAS was comparable in the three groups. A comparable number of patients also required oxycodone as rescue medication within the first 6 hours. However, 27% and 38% less oxycodone was required in the 1 g and 2 g paracetamol groups, respectively. This opioid sparing effect did not result in diminished side effects in the groups of patients who received paracetamol.
Thus, a weak effect of paracetamol has been documented but even the 2 g dose failed to attenuate side effects and consequently to improve patients’ discomfort postoperatively. The use of NSAIDs after tonsillectomy has been reported to achieve good pain control but increased the incidence of postoperative bleeding leading to rehospitalization, transfusion and/or reoperation (NNH = 30). In the current study, paracetamol decreased the opioid demand at comparable pain control in the three groups. As there was no decrease in opioid side effects, the combination of paracetamol and ketoprofen appears to have no real value in the setting of tonsillectomy. It remains to assess the effect of paracetamol alone or in combination with other non-opioid analgesics.
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