[Conventional techniques for analgesia: opioids and non-opioids. Indications, adverse effects and monitoring].
Morphine dosage must be carefully adapted in patients with renal failure or severe liver failure. The i.v. route is used for morphine titration in the post anaesthesia care unit (PACU), or for analgesia in children. Systematic (not on demand) intramuscular or subcutaneous morphine must be administered at intervals not longer than 4 hours. Dosage is best determined after i.v. titration in the PACU. Codeine, administered orally, is metabolised into morphine. Codeine has almost no effect in 7% of Caucasians and at least 15% of Asians. Nalbuphine, which has a sedative effect and a short half-life, is mainly used in children. Paracetamol (acetaminophen) is used orally or rectally, most often in combination with codeine. Paracetamol dosage is 60-90 mg.kg-1.d-1, including a 20 mg (orally), or 40 mg (rectally) loading dose. Its therapeutic ratio is low, with a potential hepatic toxicity. Dosage must be lowered in alcoholics or in patients under isoniazide therapy. Non-steroidal anti-inflammatory drugs are powerful antinociceptive agents. Their use must be restricted to the first 5 postoperative days. Their major contraindications are kidney failure, risk of gastrointestinal bleeding, coagulation disorders, allergy. They also have a marked morphine sparing effect and reduce therefore the respiratory depression induced by morphine.
Mazoit
J X
JX
Service d'anesthésie, hôpital Bicêtre, France.
D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000627:therapeutic use*; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D008991:Monitoring, Physiologic; D010149:Postoperative Pain / Q000188:drug therapy* / Q000503:physiopathology
D018712:Analgesics, Non-Narcotic; D000701:Analgesics, Opioid