Caudal tramadol (2 mg.kg-1) provided reliable postoperative analgesia similar to caudal morphine (0.03 mg.kg-1) in quality and duration of pain relief in our study children who were undergoing herniorrhaphy. We also concluded that presurgical caudal morphine or tramadol reduced perioperative sevoflurane requirements and either presurgical or postsurgical caudal morphine did not make any difference to postoperative analgesia.

Remifentanil, alfentanil, remifentanil-midazolam, and alfentanil-midazolam combinations are effective in children and can be used safely in bone marrow aspiration which is a brief but painful procedure performed in the pediatric patient group.

Tramadol used caudally is as effective as bupivacaine in the management of postoperative pain in children and the addition of tramadol to bupivacaine, when both drugs were administered caudally, did not prolong the duration of action of bupivacaine and is a safe agent in children.

Caudal administration of ketamine 0.5 mg.kg-1 with or without alfentanil in children produced satisfactory postoperative analgesia without respiratory depression or other side-effects.

The antinociceptive effect of dipyrone, a nonsteroidal anti-inflammatory drug, was studied in a series of experiments employing tail-flick and hot-plate models and the abdominal constrictor test. The drug was given via intracerebroventricular (ICV), intrathecal (IT) or subcutaneous (SC) routes. Dipyrone exhibited no analgesic activity in the tail-flick and hotplate tests while it inhibited the number of stretches in a dose-dependent manner. The antinociceptive effect of dipyrone administered by the ICV and IT routes was almost completely reversed by naloxone treatment. The same procedure attenuated but not completely inhibited the dipyrone action induced by SC administration. Histopathological examination revealed that IT dipyrone application produces no significant lesion in the spinal cord. The results suggest that dipyrone may exert a central antinociceptive action reversed by naloxone.