Effect on QTc interval by switching from methadone to equipotent R-methadone dose in methadone maintenance treatment patients.

Methadone (R,S-methadone) can prolong the QT interval. R-methadone inhibits cardiac potassium channel function less than S-methadone. We tested if switching from methadone to R-methadone would reduce corrected QT (QTc) intervals in methadone maintenance treatment (MMT) patients. Nine patients, with automatically read QTc intervals ≥450 ms, were required to detect a 20 ms (clinically relevant) reduction in QTc intervals with 15 ms standard deviation (SD) and 90% power. Nine stabilized MMT patients, using median (range) 70 (40-120) mg methadone, were included. Data (ECG recordings, serum samples, and withdrawal symptoms) were collected both before drug intake (Cmin ) and at 3 h after drug intake (Cmax ), and were collected on the day before the switch from methadone to equipotent R-methadone dose and at 14 and 28 days after the switch. A cardiologist calculated QTc intervals retrospectively. Serum electrolytes and methadone concentrations were measured. Mean QTc intervals at Cmin were 472 ms and 422 ms on methadone (automatically and manually read) and 414 ms on R-methadone (manually read). Mean (SD) change in QTc intervals was -8 (10) ms (p = 0.047) at Cmin but non-significant at Cmax . R-methadone showed a concentration-dependent relationship with QTc intervals. Switching to R-methadone reduced QTc intervals, but far less than the 20 ms considered clinically relevant.

Effects of Sleeve Gastrectomy and Roux-en-Y Gastric Bypass on Escitalopram Pharmacokinetics: A Cohort Study.

BACKGROUND: Changes in the gastrointestinal physiology after bariatric surgery may affect the pharmacokinetics of medications. Data on the impact of different surgical techniques on the pharmacokinetics of commonly prescribed antidepressants such as escitalopram are limited. METHODS: This case-only prospective study investigated escitalopram-treated patients who underwent bariatric surgery at hospitals in Central Norway. Escitalopram concentrations were assessed using serial blood samples obtained during a dose interval of 24 hours preoperatively and at 1, 6, and 12 months, postoperatively. The primary outcomes were changes in the area under the time-concentration curve (AUC 0-24 ) with secondary outcomes, including full pharmacokinetic profiling. We performed repeated-measures analysis of variance for the AUC 0-24 and secondary outcomes. RESULTS: Escitalopram-treated obese patients who underwent sleeve gastrectomy (n = 5) and Roux-en-Y gastric bypass (n = 4) were included. Compared with preoperative baseline, dose-adjusted AUC 0-24 values were within ±20% at all time points, postoperatively in the sleeve gastrectomy and oux-en-Y gastric bypass groups, with the largest changes occurring 1 month postoperatively (+14.5 and +17.2%, respectively). No statistically significant changes in any pharmacokinetic variables over time were reported; however, there was a trend toward increased maximum concentrations after surgery ( P = 0.069). CONCLUSIONS: Our findings suggest that bariatric surgery has no systematic effect on the pharmacokinetics of escitalopram. However, because of the substantial interindividual variation, therapeutic drug monitoring can be considered to guide postoperative dose adjustments.

Severe Neurological Sequelae after a Recreational Dose of LSD.

A young man with an unremarkable medical history suffered a seizure with subsequent cardiorespiratory arrest and severe neurological sequelae after ingesting a blotter. Analysis of a similar blotter and a serum sample obtained 3 h after the event detected lysergic acid diethylamide (LSD) at an amount of 300 µg in the blotter and at a concentration of 4.0 ng/mL (12.4 nmol/L) in the serum. No other drugs were present in concentrations which may confer significant effects. In addition, no individual traits which would make the patient particularly susceptible to adverse LSD effects have subsequently been identified. This suggests that LSD may confer toxic effects in previously healthy individuals.

Effect of Sleeve Gastrectomy on Buprenorphine Pharmacokinetics: A Planned Case Observation.

PURPOSE: Bariatric surgery may affect the absorption and metabolism of drugs by various mechanisms. We present a planned case observation of a patient treated with sublingual buprenorphine in an opioid maintenance treatment program, and the observed changes in buprenorphine pharmacokinetics following gastric sleeve surgery. METHODS: Serial blood samples during a dose interval of 24 hours were obtained approximately 1 year preoperatively as well as 1 week, 1 month and 12 months postoperatively and key pharmacokinetic variables were calculated. FINDINGS: The systemic exposure of buprenorphine (AUC) was relatively stable from the preoperative sampling to 1 week postoperatively (-6.3%), but declined markedly at 1 month (-43%) and 12 months (-42%) postoperatively. The maximum concentration of buprenorphine almost doubled at 1 week postoperatively before returning to baseline values 1 month and 12 months postoperatively. IMPLICATIONS: This case observation indicates that after sleeve gastrectomy, the systemic exposure of sublingual buprenorphine can decrease. Clinicians should be aware of the possibility of loss of effect and emerging abstinence symptoms following sleeve gastrectomy. We recommend monitoring the patient closely for abstinence symptoms postoperatively and considering measuring serum concentrations of buprenorphine pre- and postoperatively.

Pharmacology Portal: An Open Database for Clinical Pharmacologic Laboratory Services.

PURPOSE: More than 50 Norwegian public and private laboratories provide one or more analyses for therapeutic drug monitoring or testing for drugs of abuse. Practices differ among laboratories, and analytical repertoires can change rapidly as new substances become available for analysis. METHODS: The Pharmacology Portal was developed to provide an overview of these activities and to standardize the practices and terminology among laboratories. The Pharmacology Portal is a modern dynamic web database comprising all available analyses within therapeutic drug monitoring and testing for drugs of abuse in Norway. Content can be retrieved by using the search engine or by scrolling through substance lists. The core content is a substance registry updated by a national editorial board of experts within the field of clinical pharmacology. This ensures quality and consistency regarding substance terminologies and classification. FINDINGS: All laboratories publish their own repertoires in a user-friendly workflow, adding laboratory-specific details to the core information in the substance registry. The user management system ensures that laboratories are restricted from editing content in the database core or in repertoires within other laboratory subpages. The portal is for nonprofit use, and has been fully funded by the Norwegian Medical Association, the Norwegian Society of Clinical Pharmacology, and the 8 largest pharmacologic institutions in Norway. IMPLICATIONS: The database server runs an open-source content management system that ensures flexibility with respect to further development projects, including the potential expansion of the Pharmacology Portal to other countries.

Detection time for THC in oral fluid after frequent cannabis smoking.

BACKGROUND: The use of oral fluid for detecting drugs of abuse has become increasingly more frequent. Few studies have, however, investigated the detection times for drugs of abuse in oral fluid, compared with that of in urine or in blood. Cannabis is the world's most widely used drug of abuse, and the detection times for cannabis, in different types of matrixes, are therefore important information to the laboratories or institutions performing and evaluating drugs of abuse analyses. It is well known that frequent use of high dosages of cannabis, for longer periods of time, might lead to prolonged detection times for THC-COOH in urine. Cannabis intake is detected in oral fluid as THC, and a positive finding is considered to be a result of recent smoking, although some studies have already reported longer detection times. The aim of this study was to investigate the detection time for THC in oral fluid, collected from drug addicts admitted for detoxification. Findings in oral fluid were compared with findings in urine, among 26 patients admitted to a closed detoxification unit. METHODS: The study, being the first in doing so, describes the concentration-time profiles for THC in oral fluid among chronic cannabis users, during monitored abstinence, using the Intercept collection kit. The study also includes the concentration-time profiles for creatinine-corrected THC-COOH ratios in urine samples, included to monitor for the possibility of new intakes. RESULTS: THC was detected in oral fluid collected from 11 of the 26 patients in the study. The elimination curves for THC in oral fluid revealed that negative samples could be interspersed among positive samples several days after cessation, whereas the THC-COOH concentrations in urine were decreasing. THC was, in this study, detected in oral fluid for up to 8 days after admission. CONCLUSIONS: The study shows that frequent use of high dosages of cannabis may lead to prolonged detection times, and that positive samples can be interspersed among negative samples. These results are of great importance when THC results from oral fluid analyses are to be interpreted.