Serum therapeutic concentration of tramadol during intravenous analgesia for postoperative pain relief
- VernacularTitle:曲马多用于术后静脉镇痛时的血清治疗浓度
- Author:
Huifang XU
;
Yongman ZHU
;
Wei JIANG
;
- Publication Type:Journal Article
- From:
Chinese Journal of Anesthesiology
2001;21(4):207-209
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the serum therapeutic concentration of tramadol during intravenous analgesia for postoperative pain relief. Methods Twenty adult patients ASA Ⅰ-Ⅱ (10 male, 10 female) undergoing elective radical operation for cancer of stomach were treated with intravenous tramadol for postoperative pain relief. Patients addicted to any drug or tolerant to opioid and patients with epilepsy or liver and/or renal dysfunction were excluded. All patients were premedicated with intramuscular phenobarbital 0.1g and atropine 0.5mg. Anesthesia was induced with midazolam 0. 1mg/kg and fentanyl 5 μg/kg and intubation was facilitated with vecuronium 0.16mg/kg. Anesthesia was maintained with continuous intravenous infusion of propofol 4-6 mg@ kg 1 @ h 1, fentanyl 2-3 μg@ kg-1 @ h-1 and vecuronium 0.1mg@ kg-1@ h-1 combined with inhalation of 1% isoflurane. After surgery in ICU when patients felt slight pain (VAS 1-2), intravenous tramadol 1.5mg/kg was given as initial dose. Whenever patients felt slight pain (VAS 1-2) again, a bolus of tramadol 20 mg was given intravenously every 10 min until VAS was 0. The onset time (from the end of iv injection of initial dose of tramadol to VAS 0), the duration of action (from VAS 0 to VAS 1-2) and the time when accumulated dose of tramadol amounted to twice the initial dose were recorded. HR, MAP, respiratory rate (RR) and SpO2 were monitored and recorded before and 10, 20, 30 min after administration of tramadol. Venous blood samples were taken before each additional tramadol administration on demand for determination of serum tramadol concentration by high performance liquid chromatography. Results The mean serum therapeutic level of tramadol during period of analgesia was (370±148)ng/ml(248.6-615.7ng/ml). The mean onset time of the initial dose was (9.2± 2.1 )min. The mean duration of action was (2.3 ± 1.0)h. The time when accumulated dose of tramadol amounted to twice the initial dose was (6.4 ± 2.7)h on average. There were no significant changes in HR,MAP, RR and SpO2 after tramadol. Conclusions It is safe and effective to give intravenous tramadol for postoperative pain relief. Serum therapeutic concentration of tramadol varies greatly from patient to patient,so the dose of tramadol should be individulized.[Key Words] Pain, postoperative; Tramadol; Plasma concentration; Injections, intravenous
