Research Article
Gabriela Rocha Lauretti, Ma
Abstract
The aim of the study was to examine the perioperative analgesic effect of topical deliver of either ketamine or S(+)- ketamine in orthopaedic postoperative pain through clinical and laboratorial evaluation. 45 patients following minor orthopaedic surgery were randomized to one of three groups (n=15). Spinal anaesthesia was performed with 15 mg hyperbaric bupivacaine. Twenty min after the spinal puncture, a controlled delivery topical cream containing either 25 mg ketamine (KG), 25 mg S(+)-ketamine (+KG) or placebo (PG) was applied. Pain and adverse effects were assessed postoperatively for 24 h. Intravenous ketoprofen was available at patient request. The plasmatic concentration of ketamine and S(+)-ketamine was measured prior the spinal puncture, 30 min, 4-hour, 8-hour, 16-hour and 24-hour after topical application by High Performance Liquid Chromatography (HPLC). Time to first rescue analgesic was longer to both KG and +KG (10 hours) compared to the PG (5 hours); (p<0.05). Ketoprofen consumption (mg) in 24 hour was higher in the PG compared to the others (p<0.0005). Thirty-min after the transdermal application, ketamine and S(+)-ketamine were detectable in plasma in both KG and +KG by HPLC, and showed a dose-ranging curve during the 24-hour evaluation (p<0.02). Adverse effects were similar among groups. As conclusions, transdermal 25 mg ketamine or 25 mg S(+)- ketamine similarly prolonged the duration of analgesia following orthopaedic procedures under bupivacaine spinal blockade, demonstrated by clinical and laboratorial data.