KETOROLAC FOR POSTOPERATIVE PAIN MANAGEMENT IN CHILDREN

Ketorolac is a nonsteroidal anti-inflammatory drug (NSAID) with potent analgesic effects and a relatively low incidence of adverse effects. Numerous clinical trials of postoperative pain treatment in children h ave shown that ketorolac is as effective as the major opioid analgesic s, such as morphine, and more effective than codeine. The pharmacokine tics of ketorolac differ in children compared with adult patients afte r surgery. In children, the volume of distribution (Vd) of ketorolac i s increased by as much as 2-fold relative to that in adults. The plasm a clearance (CL) of ketorolac is also higher in children, probably bec ause of lower binding to plasma proteins. However, the elimination hal f-life (t 1/2 beta) of ketorolac is similar in children and adults bec ause t 1/2 beta is directly proportional to Vd but inversely proportio nal to CL. These pharmacokinetic differences indicate that a higher re lative dosage is required in children, but the dosage interval is simi lar in children and adults. Ketorolac can be administered intravenousl y, intramuscularly or orally. The intravenous route is preferred durin g the immediate postoperative period, until the patient can tolerate o ral medication. Intramuscular injections are not recommended in childr en, unless the intravenous route is unavailable. The recommended intra venous dosage of ketorolac in children is 0.5 mg/kg, followed either b y bolus injections of 1.0 mg/kg every 6 hours or an intravenous infusi on of 0.17 mg/kg/h. The maximum daily dosage is 90mg, and the maximum duration of treatment is 48 hours. The recommended oral dosage is 0.15 mg/kg a to a maximum of 1.0 mg/kg/day, with a maximum duration of 7 d ays. Older children may require somewhat lower dosages, while infants and young children may require slightly higher dosages to achieve the same level of pain relief. Ketorolac is not recommended for use in inf ants aged <1 year. Unlike opioid analgesics, ketorolac does not depres s ventilation, and is not associated with nausea and vomiting, urinary retention or sedation. When combined with an opioid, ketorolac exhibi ts marked opioid-sparing effects, allowing a lower dosage of opioid to be used. Clinical studies in children and adults show that the synerg istic action of ketorolac and opioids improves the degree and quality of pain relief, and reduces the incidence of opioid-related adverse ef fects such as respiratory depression, nausea/vomiting and ileus. Recov ery of bowel function after abdominal surgery uf curs sooner in ketoro lac- compared with opioid-treated patients. Ketorolac reversibly inhib its cyclo-oxygenase, and decreases the hypersensitisation of tissue no ciceptors that occurs with surgery. It also has reversible antiplatele t effects, which are attributable to the inhibition of thromboxane syn thesis. Bleeding time is usually slightly increased, but in most patie nts it remains within normal values. There is conflicting evidence of the potential for increased surgical-site bleeding after tonsillectomy but, for other types of paediatric surgery, numerous clinical studies have confirmed that ketorolac is not associated with increased bleedi ng. Thus, ketorolac is well suited for the treatment of postoperative pain in children,, either alone or in combination with opioids or loca l anaesthetics, because of its analgesic potency and relatively low in cidence of adverse effects.