RESUMO
BACKGROUND: The aim of this study was to evaluate postoperative analgesia provided by caudal S(+)-ketamine and S(+)-ketamine plus clonidine without local anesthetic. METHODS: Forty-four children aged 1-5 years consecutively scheduled for inguinal hernia repair, hydrocele repair or orchidopexy were randomly assigned to receive a caudal injection of either S(+)-ketamine 1 mg x kg(-1) (group K) or S(+)-ketamine 0.5 mg x kg(-1) plus clonidine 1 microg x kg(-1) (group KC). Postoperative analgesia and sedation were evaluated by CHEOPS and Ramsay scale from emergence from general anesthesia for 24 h. RESULTS: No statistical difference was observed between study groups with respect to pain and sedation assessment. A slight trend toward a reduced requirement for rescue analgesia in group KC was observed, although not statistically significant. CONCLUSIONS: Caudal S(+)-ketamine 1 mg x kg(-1) and S(+)-ketamine 0.5 mg x kg(-1) plus clonidine 1 microg x kg(-1) are safe and provide effective postoperative analgesia in children without adverse effects.