Journal of Physical Chemistry & Biophysics
Open Access

Abstract

Transdermal Ketamine and S(+)-Ketamine as Adjuvants Following Orthopaedic Surgery under Bupivacaine Spinal Anaesthesia

Gabriela Rocha Lauretti, Marcia Amaral, Ramon Dangelo Dias, Vera Lucia Lanchote and Anita Leocádia de Mattos

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.