Therapeutic Drug Monitoring of Naltrexone and 6ß-Naltrexol During Anti-craving Treatment in Alcohol Dependence: Reference Ranges.

AIMS: Aim of this study was to associate concentration of naltrexone and its major active metabolite 6ß-naltrexol in blood with therapeutic outcome during treatment with naltrexone in subjects with alcohol dependence. Treatment with the µ-opiate receptor antagonist naltrexone has been shown to reduce craving for alcohol and alcohol intake in patients suffering from alcohol dependence. SHORT SUMMARY: This article shows the use of therapeutic drug monitoring in alcohol dependent patients, who are treated with naltrexone. The plasma concentrations of naltrexone and 6ß-naltrexol showed high inter-individual variability. They were predictive for treatment response, as they correlated significantly with the reduction of alcohol craving. METHODS: Naltrexone and 6ß-naltrexol were analysed by high performance liquid chromatography with column switching and spectrophotometric detection. Alcohol craving was assessed with the Obsessive-Compulsive Drinking Scale (OCDS). RESULTS AND CONCLUSIONS: The study included 43 patients who were treated with naltrexone with a dose of 50 mg/day. Blood was taken for drug analysis 8 h after the last dose of the day at Week 4, 8 and 12. The plasma concentrations of naltrexone and 6ß-naltrexol showed high inter-individual variability. They were predictive for treatment response, as they correlated significantly with the reduction of alcohol craving. Defining patients with OCDS reduction of 70% or higher as responders, the mean±SD concentration of naltrexone plus naltrexol was 22 ± 13 ng/ml compared to 15 ± 8 ng/ml in patients with score reductions of 1-69%. Further analyses indicated that concentrations of 17-50 ng/ml at 8 h and 7-20 ng/ml at 24 h after drug intake were required for treatment response. CONCLUSIONS: Since plasma concentration of naltrexone plus 6ß-naltrexol was found to be predictive for reduction of alcohol craving, it is concluded that therapeutic drug monitoring has the potential to enhance naltrexone's moderate therapeutic efficiency in patients with alcohol dependence.

Serum concentrations of hydroxybupropion for dose optimization of depressed patients treated with bupropion.

BACKGROUND: Bupropion is a dopamine and norepinephrine reuptake inhibitor approved for the treatment of depression and smoking cessation. According to the recently published reviews, it is a candidate for therapeutic drug monitoring (TDM) to improve therapeutic outcomes and reduce risks of intolerability or intoxication. In practice, however, the use of TDM is limited due to the chemical instability of bupropion. This investigation sought to determine if the major, active, and chemically stable metabolite 4-hydroxybupropion is a suitable measure to guide antidepressant drug therapy with bupropion. METHODS: 4-Hydroxybupropion serum levels were measured using a newly developed and validated high-performance liquid chromatography assay with ultraviolet detection. They correlated with therapeutic effects measured by the clinical global impression scale for improvement. RESULTS: The study included 52 patients (50% women). Patients who were markedly improved according to the clinical global impression scale score had significantly (P = 0.042) higher 4-hydroxybupropion serum levels than those with moderate or minimal improvement (mean ± SD, 1113 ± 576, 825 ± 398, and 475 ± 331 ng/mL, respectively). Analysis of receiver operating characteristics revealed significant predictive properties of 4-hydroxybupropion serum levels (P = 0.002) for marked improvement with a lower threshold level of 858 ng/mL. Under similar mean doses (265 ± 107 versus 239 ± 100 mg, respectively), women attained significantly higher serum levels than men (1050 ± 524 versus 589 ± 352 ng/mL, respectively) and exhibited a better therapeutic effect (P = 0.018). CONCLUSIONS: Despite multiple limitations of this naturalistic study, evidence could be given that the measurement of 4-hydroxybupropion in serum is suitable to perform TDM for bupropion. Blood levels should be above 860 ng/mL to attain therapeutic improvement. Potential sex differences in bupropion pharmacokinetics, probably due to differential activities of CYP2B6, should be taken into account when the drug is prescribed.

Evaluation of naltrexone for dissociative symptoms in borderline personality disorder.

Data from a pilot study suggest that naltrexone might reduce dissociative symptoms in patients with borderline personality disorder. However, the interpretation of these data is limited by the lack of a control group and by the nonblind nature of this study. Hence, we examined the effects of naltrexone using a more rigorous design that controlled for major confounders such as spontaneous reduction of dissociation over time and placebo effects. Unmedicated patients with BPD [according to Diagnostic and Statistical Manual of Mental Disorders-IVth edition (DSM-IV)] were included in two small double-blind placebo-controlled randomized trials (total n=29). Patients received both 3 weeks of naltrexone (50 or 200 mg/day) and 3 weeks of placebo in a randomized order. Twenty-five patients completed the study according to protocol. Dissociation under naltrexone and placebo, respectively, was compared by repeated-measures analyses of variance. In either trial, both the intensity and duration of dissociative symptoms were numerically lower under naltrexone than under placebo. However, the effects were too small to reach statistical significance. Our data provide the first estimate of the pure pharmacological antidissociative efficacy of naltrexone from a rigorously designed trial.

Therapeutic drug monitoring for drugs used in the treatment of substance-related disorders: literature review using a therapeutic drug monitoring appropriateness rating scale.

BACKGROUND: The efficacy of drugs for the treatment of substance-related disorders is moderate at best. Therapeutic drug monitoring (TDM) could be an instrument to improve outcomes. Because TDM for most of those drugs is not established, the authors reviewed the literature and built a rating scale to detect the potential added value of TDM for these pharmacologic agents. METHODS: A literature search was performed for acamprosate, bupropion, buprenorphine, clomethiazole, disulfiram, methadone, naltrexone, and varenicline. The rating scale included 22 items and was divided in five categories: efficacy, toxicity, pharmacokinetics, patient characteristics, and cost-effectiveness. Three reference substances with established TDM were similarly assessed for comparison: clozapine, lithium, and nortriptyline. The three reference substances achieved scores of 15, 12, and 14 points, respectively. RESULTS: Drugs for treatment of substance-related disorders achieved 3 to 17 points, 17 for methadone, 11 for buprenorphine, 10 for disulfiram, also 10 for naltrexone for the indication opioid-dependence and 9 for the indication alcohol dependence as well as bupropion, 7 points for acamprosate, 6 points for clomethiazole, and 3 for varenicline. CONCLUSIONS: It is concluded that systematic evaluation of drug- and patient-related variables with the new rating scale can estimate the appropriateness of TDM. Because their rating revealed similar scores as the three reference drugs, it is proposed that TDM should be established for bupropion, buprenorphine, disulfiram or a metabolite, methadone, and naltrexone. An objective rating of drug- and patient-related characteristics could help laboratories focus their method development on the most likely drugs to require TDM along with a thorough drug use evaluation.

Determination of naltrexone and 6beta-naltrexol in human blood: comparison of high-performance liquid chromatography with spectrophotometric and tandem-mass-spectrometric detection.

We present data for a comparison of a liquid-chromatographic method coupled with tandem mass spectrometry (LC-MS/MS) and a high-performance liquid-chromatographic method with column switching and UV spectrophotometric detection. The two methods were developed for determination of naltrexone and 6beta-naltrexol in blood serum or plasma aiming to be used for therapeutic drug monitoring to guide the treatment of patients with naltrexone. For the high-performance liquid chromatography (HPLC)/UV detection, online sample cleanup was conducted on Perfect Bond C(18) material with 2% (vol/vol) acetonitrile in deionized water. Drugs were separated on a C(18) column using 11.5% (vol/vol) acetonitrile and 0.4% (vol/vol) N,N,N,N-tetramethylethylenediamine within 20 min. LC-MS/MS used naltrexone-d (3) and 6beta-naltrexol-d (4) as internal standards. After protein precipitation, the chromatographic separation was performed on a C(18) column by applying a methanol gradient (5-100%, vol/vol) with 0.1% formic acid over 9.5 min. The HPLC/UV method was found to be linear for concentrations ranging from 2 to 100 ng/ml, with a regression correlation coefficient of r (2) > 0.998 for naltrexone and 6beta-naltrexol. The limit of quantification was 2 ng/ml for naltrexone and 6beta-naltrexol. For the LC-MS/MS method the calibration curves were linear (r(2) > 0.999) from 0.5 to 200 ng/ml for both substances, and the limit of quantification was 0.5 ng/ml. The concentrations measured by the two methods correlated significantly for both substances (r(2) > 0.967; p < 0.001). Both methods could be used for therapeutic drug monitoring. The HPLC/UV method was advantageous regarding automatization and costs, whereas LC-MS/MS was superior with regard to sensitivity.