Intensity of Withdrawal Symptoms During Opioid Taper in Patients with Chronic Pain-Individualized or Fixed Starting Dosage?

OBJECTIVE: Controlled opioid withdrawal is recommended for patients with chronic noncancer pain (CNCP) with insufficient pain reduction or intolerable side effects while on opioid treatment. Few studies have investigated the management of opioid withdrawal (OW). Most common are protocols with an individualized starting dosage (ISD), calculated from the last opioid intake. After two cases of overdose, we introduced a novel withdrawal protocol using a low fixed starting dosage (FSD) for safety reasons. The present study compares the intensity of withdrawal symptoms using the Subjective Opioid Withdrawal Scale (SOWS) and incidences of serious adverse events (SAE) and dropouts in each taper schedule in 195 CNCP patients with OW in an inpatient facility. METHODS: Two protocols were compared: FSD (2014-2016): N = 68, starting dose: 90 mg morphine/d; and ISD (2010-2014): N = 127, starting dose: 70% of the patient's daily morphine equivalent dose (MED). Outcome criteria: primary: mean daily SOWS score during the first 10 days (16 questions, daily score 0-64); secondary: change in pain intensity on a numeric rating scale (0-10), rate of dropouts and SAEs. Statistics: Student test, Mann-Whitney U test, chi-square test, analysis of variance, P < 0.05. RESULTS: The mean daily SOWS score was lower in the FSD group (14.9 ± 9.4 vs 16.1 ± 10, P < 0.05) due to a lower rate of high-intensity withdrawal symptoms (12.4% vs 17.6%, P < 0.01), particularly in patients on >180 mg MED (9.7% vs 18.4%, P < 0.01). Pain intensity decreased after withdrawal, and the incidence of SAEs and dropouts was low in both groups. CONCLUSIONS: The FSD protocol provides a lesser burden of withdrawal symptoms and equal patient safety. It can be recommended for OW in CNCP patients.

Short-Term Glucocorticoid Treatment Normalizes the Microcirculatory Response to Remote Ischemic Conditioning in Early Complex Regional Pain Syndrome.

BACKGROUND: The early phase of complex regional pain syndrome (CRPS) is characterized by an inflammatory state and therefore often treated with anti-inflammatory acting glucocorticoids. Recently, we demonstrated that remote ischemic conditioning (RIC), a cyclic application of nondamaging ischemia on a remote extremity, reduces blood flow and increases oxygen extraction in the CRPS-affected extremity. AIM: The aim of the presented study was to analyze the effect of short-term pain treatment including glucocorticoid pulse treatment on the RIC-induced perfusion parameters. METHOD: Independently from the study, pain treatment was started with an oral glucocorticoid pulse (180 to 360 mg prednisolone) in 12 patients with CRPS (disease duration < 1 year). RIC was conducted before and after pulse treatment. Three cycles of 5 minutes ischemia and 10 minutes reperfusion were applied to the contralateral limb. Blood flow, tissue oxygenation, and oxygen extraction fraction were assessed ipsilateral before and during RIC. Current pain was assessed on the numeric rating scale (0 to 10), and finger-palm distance was measured. RESULTS: Pain level (5.8 ± 1.5 vs. 3.1 ± 1.1) and finger-palm distance (5 ± 1.9 cm vs. 3.7 ± 1.9 cm) were decreased significantly by the treatment. RIC decreased blood flow by 32.8% ± 42.8% (P < 0.05) and increased oxygen extraction fraction by 8.5% ± 10.3% (P < 0.05) solely before the treatment. After treatment, all parameters remained unchanged after RIC (P < 0.05 vs. before), comparable to healthy subjects. CONCLUSION: Confirming previous results, RIC presumably unmasks luxury perfusion in untreated CRPS patients. In accordance with the clinical improvement, the short-term pain treatment with glucocorticoids as major component normalizes impaired perfusion. These results might underline the rationale for anti-inflammatory treatment in early-phase CRPS.

Verification of propofol sulfate as a further human propofol metabolite using LC-ESI-QQQ-MS and LC-ESI-QTOF-MS analysis.

BACKGROUND: Propofol (2,6-diisopropylphenol) is a water-insoluble, intravenous anesthetic that is widely used for the induction and maintenance of anesthesia as well as for endoscopic and pediatric sedation. After admission, propofol undergoes extensive hepatic and extrahepatic metabolism, including direct conjugation to propofol glucuronide and hydroxylation to 2,6-diisopropyl-1,4-quinol. The latter substance subsequently undergoes phase II metabolism, resulting in the formation of further metabolites (1quinolglucuronide, 4quinolglucuronide and 4quinol-sulfate). Further minor phase I propofol metabolites (2-(ω-propanol)-6-isopropylphenol and 2-(ω-propanol)-6-isopropyl-1,4-quinol)) are also described. Due to its chemical structure with the phenolic hydroxyl group, propofol is also an appropriate substrate for sulfation by sulfotransferases. METHODS: The existence of propofol sulfate was investigated by liquid chromatography electrospray ionization triple quadrupole mass spectrometry (LCESIQQQ-MS) and liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LCESI-QTOF-MS). A propofol sulfate reference standard was used for identification and method development, yielding a precursor at m/z 257 (deprotonated propofol sulfate) and product ions at m/z 177 (deprotonated propofol) and m/z 80 ([SO3]-). RESULTS: Propofol sulfate - a further phase II metabolite of propofol - was verified in urine samples by LC-ESI-QQQ-MS and LC-ESI-QTOF-MS. Analyses of urine samples from five volunteers collected before and after propofol-induced sedation verified the presence of propofol sulfate in urine following propofol administration, whereas ascertained concentrations of this metabolite were significantly lower compared with detected propofol glucuronide concentrations. CONCLUSIONS: The existence of propofol sulfate as a further phase II propofol metabolite in humans could be verified by two different detection techniques (LCESIQQQ-MS and LC-ESI-QTOFMS) on the basis of a propofol sulfate reference standard. Evaluation of the quantitative analyses of propofol sulfate imply that propofol sulfate represents a minor metabolite of propofol and is only slightly involved in human propofol clearance.

1,2-Dimethylimidazole-4-sulfonyl chloride (DMISC), a novel derivatization strategy for the analysis of propofol by LC-ESI-MS/MS.

Analysis of the anesthetic agent propofol in biological samples by LC-MS/MS is a great challenge due to weak fragmentation and poor ionization efficacy of propofol resulting in weak signal intensities. Improvements of the ionization and fragmentation efficacy can be achieved by conversion of propofol to its dimethylimidazolesulfonyl (DMIS) derivative by a derivatization reaction using 1,2-dimethylimidazole-4-sulfonyl chloride (DMISC). This DMIS derivative produced intense [M + H]+ ions in positive-ion LC-ESI-MS/MS with the dimethylimidazole moieties representing the most abundant product ions. Derivatization of serum samples is achieved by direct conversion of the acetonitrile supernatant of a protein precipitation with DMISC followed by a double liquid-liquid extraction using n-hexane. Reliability of the method was confirmed under consideration of the validation parameters selectivity, linearity, accuracy and precision, analytical limits, and processed sample stability. Linearity was demonstrated over the whole calibration range from 5 to 1000 ng/ml with the use of a 1/x 2 weighting. Stability of the processed samples was verified for a time period of up to 25 h. Due to its high sensitivity, appropriate quantification and detection limits (LLoQ = 5 ng/ml, LoD = 0.95 ng/ml) for toxicological propofol analyses could be achieved. Applicability of the method to biological samples could be verified by analysis of a human serum sample collected after propofol-induced sedation. Graphical abstract A novel derivatization strategy using 1,2-dimethylimidazole-4-sulfonyl chloride (DMISC) was developed to improve the ionization and fragmentation efficacy of propofol for LC-ESI-MS/MS analysis.