Cross-Reactivity of Tapentadol Specimens with DRI Methadone Enzyme Immunoassay.

Filed under: Methadone Side Effects

J Anal Toxicol. 2012 Aug 9;
Collins AA, Merritt AP, Bourland JA

A substantial incidence of positive methadone screens for pain management urine specimens using a commercial enzyme immunoassay (EIA) was observed in the absence of a methadone prescription, with negative methadone confirmation by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS-MS). Tapentadol was the only common prescription among the investigated specimens. Tapentadol or one of its three major metabolites was tested at various concentrations (100-200,000 ng/mL) against the DRI EIAs for methadone and methadone metabolite, to evaluate cross-reactivity. Ninety-seven authentic tapentadol urine specimens that produced false-positive methadone EIA results (cutoff = 130 ng/mL) were analyzed for methadone and tapentadol in compound-specific UPLC-MS-MS confirmation tests. Tapentadol, tapentadol glucuronide, tapentadol sulfate and N-desmethyltapentadol exhibited cross-reactivity with the methadone EIA at 6,500 (2.2%), 25,000 (0.6%), 3,000 (4.4%) and 20,000 ng/mL (0.9%), respectively. No cross-reactivity was observed with the methadone metabolite 2-ethylidine-1,5-dimethyl-3,3-diphenylpyrrolidine EIA. All authentic urine specimens were confirmed to be negative for methadone, but positive for tapentadol and all monitored metabolites. Individual concentrations indicated that separate or combined urinary concentrations of tapentadol and its conjugates may produce false-positive methadone screens through cross-reactivity with the methadone immunoassay. The potential for false-positive results for methadone EIA screening of urine specimens associated with tapentadol prescriptions should be considered when interpreting results.
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Prevalence of common chronic respiratory diseases in drug misusers: a cohort study.

Filed under: Methadone Side Effects

Prim Care Respir J. 2012 Aug 8;
Palmer F, Jaffray M, Moffat MA, Matheson C, McLernon DJ, Coutts A, Haughney J

BACKGROUND: A randomised controlled trial of substance misuse indicated that many patients who use methadone have respiratory symptoms and/or are prescribed respiratory medications. There is little research in this area. AIMS: To determine the prevalence of respiratory disease and prescriptions among drug misusers. METHODS: This historical cohort study of drug misusers and matched controls analysed routinely collected primary care data. The prevalence of common chronic respiratory diseases, class and number of respiratory medications were examined. RESULTS: The cohort of 18,570 patients (9,285 per group) was mostly male (64%, n=11,890) and aged 31-59 years (76%, n=14,060). After adjusting for age, gender, deprivation and smoking status, the results showed that more drug misusers than controls had a diagnosis of asthma or chronic obstructive pulmonary disease (17.1% vs. 10.9%; adjusted odds ratio (OR) 1.61, 95% confidence interval (CI) 1.46 to 1.77, and 2.4% vs. 0.8%; OR 1.86, 95% CI 1.42 to 2.44, respectively) and were prescribed more chronic respiratory medications: short-acting ?2-agonists (16.4% vs. 7.9%; OR 2.00, 95% CI 1.80 to 2.22), long-acting ?2-agonists (1% vs. 0.4%; OR 1.93, 95% CI 1.29 to 2.89), and inhaled corticosteroids (10.6% vs. 7.6%; OR 1.49, 95% CI 1.33 to 1.67). All differences were statistically significant (p<0.001). CONCLUSIONS: Drug misusers have a significantly higher prevalence of respiratory diseases and respiratory prescriptions than matched controls. Further work is needed to determine the reasons for this. Source

[Psychiatric Disorders Associated with High-dose Methadone (>100 mg/d): A Retrospective Analysis of Treated Patients].

Filed under: Methadone Side Effects

Therapie. 2012 May-Jun; 67(3): 223-30
Eiden C, Leglise Y, Clarivet B, Blayac JP, Peyrière H

Background. Recent studies show that high-dose methadone (>100 mg/d) allow a better control of the consumptions of illicit opiates by treated patients. Objective. The aim of this retrospective study was to analyze data of patients requiring high-dose methadone (>100 mg/d) as well as associated factors. Methods. We retrospectively reviewed charts of treated patients with high-dose methadone followed in the maintenance methadone treatment center between 01/01/07 and 01/07/10. The following variables (medical history, psychiatric comorbidities, associated drugs, and polyaddictions), were assessed with high-dose methadone, using an univariate and then a multavariate analysis. The threshold value of 130 mg/day (median of maximal daily dose) was used to perform analysis. Results. During the study period, 78 patients, mainly men (75.6%), with a median age of 34 years [22-57] were included. The both groups with posology of methadone ? 130 mg/d (n=44) versus posology of methadone  >130 mg/d (n=34) were close in term of demographic characteristics, consumption of drugs and associated treatments. Plasma methadone concentrations were higher in patients with the daily doses of methadone superior than 130 mg/d (NS), as well as the methadone metabolite (EDDP, p=0.048). Among studied factors, the presence of psychiatric comorbidities was significantly associated with high-dose methadone (threshold 130 mg/d) [OR 4,6 IC 95% (1.412;14.925)]. Seven patients presented with complications related to methadone: cardiac disorder (3), libido troubles (3) and hypofertility (1). Conclusion. Patients requiring high-dose methadone are polydrug addicts. In our study, patients with psychiatric comorbidities needed daily dose of methadone significantly more raised.
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