Morphine (MS Contin) [BSA]

Background: An increasing number of patients come to the operating room in use of opioid analgesics. They have different levels of tolerance to opioid effects which challenge the anesthesiologists in search of safe and effective opioid dosing perioperatively. The tested hypothesis is that simple measures introduced will allow us to measure tolerance qualitatively. Opioid effects on pain (analgesia) and dyspnea sensations (relieving effect) are tested. Patients were allocated to three groups according to pre-operative analgesics: (1) control, without any opioid analgesics, (2) weak opioid, and (3) strong opioid. Pressure pain threshold (PPT) and no-respiratory sensation period (NRSP) were measured at two points: before and 3 min after intravenous fentanyl administration. Results: A total of 58 (43 controls, 9 weak opioids, and 6 strong opioids) patients were enrolled. PPT and NRSP, after iv 2 mu g/kg ideal body weight (IBW) fentanyl, were significantly elevated in the control patients (PPT: 6.2 +/- 2.1 N to 9.2 +/- 3.9 N, p < 0.0001, NRSP: 17.8 +/- 10.8 s to 22.8 +/- 18.7 s,p< 0.005, pairedttest). However, preoperative opioid use, though with tendency, did not show a significant decrease of the opioid effect. Due to an insufficient number of participants, no conclusion could be drawn. Further analysis of the data from control patients showed a significant difference between the two sexes in sensitivity to PPT and NRSP, as well as fentanyl effect on PPT. Conclusions: Current data showed a simple method of measuring the opioid effect on two dimensions: pain and respiration. Though not able to show a qualitative measurement of tolerance formation in opioid-users, data from control patients showed females to be more sensitive to pain and dyspnea but is less sensitive to the opioid effect. Further studies are necessary to show whether these gender differences serve as clinical relevance.

A rapid and sensitive method utilizing flash evaporation-gas chromatography/mass spectrometry (FE-GC/MS) has been developed. The method is applicable to determine ketamine (KET), methamphetamine (MAMP) and 3,4-methylenedioxymethamphetamine (MDMA) in human hair. Cut and weighted hair (0.30 mg) was heated at the flash evaporation temperature of 350 degrees C. KET, MAMP and MDMA were released into a capillary column for GC/MS analysis and produced fragment ions in SIM mode. Validation of the method included evaluation of linearity, sensitivity, accuracy, precision and repeatability. Linearity ranged from 2 to 300 ng/mg for KET in hair and 2 to 200 ng/mg for MAMP and MDMA in hair with the correlation coefficients all greater than 0.998. Limits of detection were 0.7 ng/mg and limits of quantification were 2.0 ng/mg of hair for KET, MAMP and MDMA. The precision ranged from 1.57% to 7.75% for KET, 1.49% to 7.10% for MAMP and 1.84% to 8.31% for MDMA. The recovery ranged from 102.1% to 110.9% for KET, 99.3% to 108.0% for MAMP and 89.5% to 112.6% for MDMA. Six authentic hair samples from known drug abusers and three drug-free hair samples from volunteers who had never used drugs were successfully analyzed. Compared with traditional time-consuming and hair-comsuming pretreatment method, FE-GC/MS was a faster, simpler and low sample consumption method for the determination of KET, MAMP and MDMA in human hair.