Consensus Guidelines for Therapeutic Drug Monitoring in Neuropsychopharmacology: Update 2017.

Therapeutic drug monitoring (TDM) is the quantification and interpretation of drug concentrations in blood to optimize pharmacotherapy. It considers the interindividual variability of pharmacokinetics and thus enables personalized pharmacotherapy. In psychiatry and neurology, patient populations that may particularly benefit from TDM are children and adolescents, pregnant women, elderly patients, individuals with intellectual disabilities, patients with substance abuse disorders, forensic psychiatric patients or patients with known or suspected pharmacokinetic abnormalities. Non-response at therapeutic doses, uncertain drug adherence, suboptimal tolerability, or pharmacokinetic drug-drug interactions are typical indications for TDM. However, the potential benefits of TDM to optimize pharmacotherapy can only be obtained if the method is adequately integrated in the clinical treatment process. To supply treating physicians and laboratories with valid information on TDM, the TDM task force of the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) issued their first guidelines for TDM in psychiatry in 2004. After an update in 2011, it was time for the next update. Following the new guidelines holds the potential to improve neuropsychopharmacotherapy, accelerate the recovery of many patients, and reduce health care costs.

[Neuroleptic malignant syndrome]. / Das maligne neuroleptische Syndrom.

BACKGROUND: Neuroleptic malignant syndrome (NMS) is a rare but severe undesired complication of psychopharmacological treatment. The mortality has shown a significant decrease since its first description. Knowledge of NMS is important for every clinician because of the need for rapid diagnosis and treatment. OBJECTIVE: This article presents a review and critical appraisal of the current study situation for NMS. Recommendations for diagnostics, differential diagnostics and treatment are presented particularly from a clinical perspective. MATERIAL AND METHODS: A literature review with the keywords "neuroleptic malignant syndrome", "Malignes neuroleptisches Syndrom" and various psychotropic drugs was performed in PubMed. The database of the Working Group for Pharmaceutical Treatment of Psychiatric Diseases (Arbeitsgemeinschaft für Arzneimitteltherapie bei psychiatrischen Erkrankungen, AGATE) was analyzed with respect to registered cases of the undesired side effect NMS. RESULTS: In contrast to the first description, which also led to the name, there are now case reports of clinical conditions similar to NMS, which were obviously triggered by several groups of psychotropic drugs not just antipsychotic agents (German: Neuroleptika). Treatment recommendations exist whereby the effectiveness cannot always be scientifically substantiated; however, it is still undisputed that a rapid initiation of treatment is of great importance. DISCUSSION: The psychiatrist must be familiar with the symptoms of NMS, its differential diagnosis and the therapeutic options for a rapid and effective treatment. Further studies are urgently needed for scientific substantiation of the pathophysiology of NMS and to develop evidence-based guidelines for treatment.

[All-rounder vitamin D?] / Alleskönner Vitamin D?

BACKGROUND: Many indications are discussed for vitamin D substitution, such as osteoporosis, autoimmune diseases, cancer and psychiatric diseases. Also discussed is the fact that the majority of the German population suffer from a vitamin D deficiency. OBJECTIVE: Review of the study results for these individual diseases and a critical analysis of the currently established therapeutic reference range, which defines a vitamin D deficiency. MATERIAL AND METHODS: A literature search was carried out in the statements of the German Society for Nutrition, in scientific publications and journals. RESULTS: The study results on prevention and therapy of various diseases with vitamin D show inconsistent results. Well-established indications are the prevention of rickets in babies and the supportive therapy for osteoporosis. The currently established reference range for the definition of a vitamin D deficiency came from studies where vitamin D deficiency was correlated to an increase in parathyroid hormone. Different laboratories use different methods for measurement of vitamin D levels. CONCLUSION: More studies are needed to clarify the role of vitamin D in the prevention and treatment of various diseases. Another problem is that different laboratories do not use the same measurement methods to determine vitamin D and the use of different methods leads to widely varying results which cannot be compared. Therefore, a standardization of the methods would be desirable.

Retrospective analysis of therapeutic drug monitoring data for treatment of bipolar disorder with lamotrigine.

INTRODUCTION: Lamotrigine is licensed for treatment of epilepsy and prevention or at least delay of depressive episodes in bipolar disorder. The accepted therapeutic reference range (TRR) of lamotrigine for anticonvulsant treatment is 3 000-14 000 ng/ml. This TRR is often used for the therapy of bipolar disorders as well. This work presents serious doubts about this approach. METHODS: KONBEST, a large TDM database containing patients' characteristics including diagnoses, doses, comedication and serum concentrations, was analyzed. Out of a total of 3 459 lamotrigine samples, 360 patients suffered from bipolar disorder. 82 of them benefitted from therapy with lamotrigine as judged by the clinical global impression of improvement (CGI-I) scale. Patients with a score of minimally (3), much (2) or very much improved (1) were considered as responders. RESULTS: The recommended lamotrigine maintenance dose for bipolar disorder is 200 mg/day; the doses prescribed in our samples ranged from 25 to 450 mg/day. Only 32 concentrations (39.0%) fitted into the TRR recommended for therapy of epilepsy; 50 (61.0%) did not reach it, none exceeded it. The lowest concentration was 177 ng/ml, the highest 11 871 ng/ml. A mean lamotrigine serum concentration of 3 341±2 563 ng/ml (̅x±SD) was detected in the patients who benefitted. DISCUSSION: The authors conclude that in bipolar disorder lower lamotrigine serum concentrations lead to therapeutic benefit.

Enhancing neurosteroid synthesis--relationship to the pharmacology of translocator protein (18 kDa) (TSPO) ligands and benzodiazepines.

INTRODUCTION: The treatment of anxiety disorders is still a challenge; novel pharmacological approaches that combine rapid anxiolytic efficacy with fewer side effects are needed. A promising target for such compounds is the mitochondrial translocator protein (18 kDa) (TSPO). TSPO plays an important role for the synthesis of neurosteroids, known to modulate GABAA receptors, thereby exerting anxiolytic effects. METHODS: We investigated the pharmacological profile of 2 well established TSPO ligands (XBD173 and etifoxine) compared to the benzodiazepine diazepam with regard to TSPO binding affinity, TSPO expression and neurosteroidogenesis. RESULTS: In BV-2 microglia and C6 glioma cells all compounds significantly enhanced TSPO protein expression. Radioligand binding assays revealed the highest binding affinity to TSPO for XBD173, followed by diazepam and etifoxine. Pregnenolone synthesis was most potently enhanced by etifoxine. DISCUSSION: Etifoxine turned out to be the most potent enhancer of neurosteroidogenesis, although its binding affinity to TSPO was lowest. These results indicate that the efficacy of TSPO ligands to stimulate neurosteroid synthesis, thereby leading to anxiolytic effects cannot be concluded from their binding affinity to TSPO.

Steady-state serum concentrations of venlafaxine in patients with late-life depression. Impact of age, sex and BMI.

Diagnosis of late-life depression is given when depressive symptoms emerge in persons older than 65 years. Great care is needed when elderly patients receive psychopharmacotherapy due to altered pharmacokinetic status. As a consequence, age is considered to have a significant effect on serum concentrations of antidepressant drugs. The magnitudes of age-dependent changes, however, are uncertain. By utilizing a large therapeutic drug monitoring (TDM) database, this cross-sectional study aimed to retrospectively assess pharmacotherapy in elderly patients in comparison with their younger counterparts, when treated with venlafaxine, which is widely used to treat late-life depression. In addition, the influence of sex and body mass index (BMI) was evaluated. Serum concentrations of venlafaxine and its active metabolite O-desmethylvenlafaxine requested during routine TDM in two University Medical Centers in Germany were analyzed. Patients with concomitant CYP2D6 inhibiting drugs as co-medication were excluded. In total, 1,417 samples were available for the analysis. Elderly patients had by average 42% higher dose-adjusted serum concentrations (ng/mL/mg) of the active moiety (venlafaxine plus O-desmethylvenlafaxine) than younger patients. In addition, our study demonstrated that the difference between age groups is independent of sex and BMI. However, age groups only explain 4.5% of the total dose-adjusted serum concentration variation of the venlafaxine active moiety. Dose adjustments for venlafaxine are recommended in patients aged 65 years or older, particularly in elderly female patients who are exceptionally vulnerable to high serum concentrations of venlafaxine. TDM is recommended during venlafaxine pharmacotherapy.

Influence of concomitant medications on the total clearance and the risk for supra-therapeutic plasma concentrations of Citalopram. A population-based cohort study.

INTRODUCTION: The main objective of this study was to investigate the influence of the use of multiple medications and other risk factors on citalopram plasma concentrations. METHODS: A retrospective cohort study with a naturalistic population of 957 patients for whom routine therapeutic drug monitoring (TDM) of citalopram had been requested between 2006 and 2013 was conducted. RESULTS: Concomitant drugs inhibiting at least 2 different CYP subtypes involved in the metabolism of citalopram decreased statistically significantly the total clearance (Clt). Compared to younger patients over 64-year-old patients had on average a 4.5 times higher risk rate of supra-therapeutic plasma concentrations. However, binary logistic regression showed that age, sex and co-medication accounted only for 26% of the inter-individual variability of citalopram plasma concentrations. DISCUSSION: Due to pharmacokinetic interactions, citalopram plasma concentrations are often higher than expected with a given dose. Especially in geriatric and often multimorbid patients who are usually prescribed high numbers of concomitant drugs and are at higher risk for adverse drug reactions (ADR), restriction of the maximal dose of citalopram is not sufficient to prevent supra-therapeutic plasma concentrations.

[Drug-drug interactions: interactions between xenobiotics]. / Arzneimittelinteraktionen : Interaktionen zwischen körperfremden Substanzen.

Drug-drug interactions (DDI) are a major topic in programs for continuous medical education (CME). Many physicians are afraid of being trapped into charges of malpractice; however, DDI cannot be avoided in many cases. They belong to routine medical practice and it is often impossible to avoid them. Moreover, they do not just occur between drugs but between any kind of foreign substance (xenobiotica), such as food (e.g. grapefruit juice, broccoli, barbecue) as well as legal (e.g. tobacco smoke, caffeine and alcohol) and illegal drugs. Therefore, the medical challenge is not just to avoid any interaction. Instead the physician faces the question of how to proceed with drug treatment in the presence of such interactions. Based on the medical education a physician has to judge first of all whether there is a risk for interactions in the prescription being planned for an individual patient. The classification of interactions proposed in this article (PD1-PD4, PK1-PK3) might help as a sort of check list. For more detailed information the physician can then consult one of the many databases available on the internet, such as PSIAConline (http://www.psiac.de) and MediQ (http://www.mediq.ch). Pharmacokinetic interactions can be easily assessed, monitored and controlled by therapeutic drug monitoring (TDM). Besides these tools it is important to keep in mind that nobody knows everything; even physicians do not know everything. So take pride in asking someone who might help and for this purpose AGATE offers a drug information service AID (http://www.amuep-agate.de). Just good for nothing, without being based on any kind of medical approach are computer programs that judge prescriptions without taking into account a patient's individual peculiarities. In case these types of programs produce red exclamation marks or traffic lights to underline their judgment, they might even work in a contrapuntal way by just eliciting insecurity and fear.

The effect of age, sex, smoking and co-medication on serum levels of venlafaxine and O-desmethylvenlafaxine under naturalistic conditions.

INTRODUCTION: Venlafaxine (VEN) is a modern antidepressant which exerts both serotonin and norepinephrine reuptake inhibition. In this study we examined the influence of age, sex, smoking, and co-medication on serum levels of VEN and its metabolite O-desmethylvenlafaxine (ODVEN) in patients treated with VEN under naturalistic conditions. METHODS: We retrospectively evaluated 478 TDM analyses of VEN requested in the Pychiatric University Hospitals of Mainz, Regensburg, and Würzburg. The determination of serum levels was performed by virtually identical chromatographic methods in the TDM laboratories of the participating hospitals. RESULTS: Serum levels varied widely on each dose level. Women had about 30% higher dose-corrected serum levels of VEN and ODVEN than men (p<0.01), and patients older than 60 years showed about 46% higher levels of both compounds than younger ones (p<0.01). In smokers, mean serum levels of ODVEN were 21% lower than in non-smokers. Combining these variables a considerable increase of the differences between the subgroups was found indicating an additive effect. ANOVA over the 8 different groups was significant for ODVEN (p<0.01) and sum (p<0.01), but not for VEN (n.s.). Co-medication with other psychotropic drugs was associated with a decreasing ODVEN/VEN ratio indicating a reduced metabolism in patients receiving polypharmacy. DISCUSSION: These findings show that TDM is useful to identify factors affecting the pharmacokinetic properties of VEN. It is concluded that sex, age and smoking should be considered for optimal dosing of patients with VEN.

AGNP consensus guidelines for therapeutic drug monitoring in psychiatry: update 2011.

Therapeutic drug monitoring (TDM), i. e., the quantification of serum or plasma concentrations of medications for dose optimization, has proven a valuable tool for the patient-matched psychopharmacotherapy. Uncertain drug adherence, suboptimal tolerability, non-response at therapeutic doses, or pharmacokinetic drug-drug interactions are typical situations when measurement of medication concentrations is helpful. Patient populations that may predominantly benefit from TDM in psychiatry are children, pregnant women, elderly patients, individuals with intelligence disabilities, forensic patients, patients with known or suspected genetically determined pharmacokinetic abnormalities or individuals with pharmacokinetically relevant comorbidities. However, the potential benefits of TDM for optimization of pharmacotherapy can only be obtained if the method is adequately integrated into the clinical treatment process. To promote an appropriate use of TDM, the TDM expert group of the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) issued guidelines for TDM in psychiatry in 2004. Since then, knowledge has advanced significantly, and new psychopharmacologic agents have been introduced that are also candidates for TDM. Therefore the TDM consensus guidelines were updated and extended to 128 neuropsychiatric drugs. 4 levels of recommendation for using TDM were defined ranging from "strongly recommended" to "potentially useful". Evidence-based "therapeutic reference ranges" and "dose related reference ranges" were elaborated after an extensive literature search and a structured internal review process. A "laboratory alert level" was introduced, i. e., a plasma level at or above which the laboratory should immediately inform the treating physician. Supportive information such as cytochrome P450 substrate and inhibitor properties of medications, normal ranges of ratios of concentrations of drug metabolite to parent drug and recommendations for the interpretative services are given. Recommendations when to combine TDM with pharmacogenetic tests are also provided. Following the guidelines will help to improve the outcomes of psychopharmacotherapy of many patients especially in case of pharmacokinetic problems. Thereby, one should never forget that TDM is an interdisciplinary task that sometimes requires the respectful discussion of apparently discrepant data so that, ultimately, the patient can profit from such a joint eff ort.

AGNP Consensus Guidelines for Therapeutic Drug Monitoring in Psychiatry: Update 2011.

Therapeutic drug monitoring (TDM), i. e., the quantification of serum or plasma concentrations of medications for dose optimization, has proven a valuable tool for the patient-matched psychopharmacotherapy. Uncertain drug adherence, suboptimal tolerability, non-response at therapeutic doses, or pharmacokinetic drug-drug interactions are typical situations when measurement of medication concentrations is helpful. Patient populations that may predominantly benefit from TDM in psychiatry are children, pregnant women, elderly patients, individuals with intelligence disabilities, forensic patients, patients with known or suspected genetically determined pharmacokinetic abnormalities or individuals with pharmacokinetically relevant comorbidities. However, the potential benefits of TDM for optimization of pharmacotherapy can only be obtained if the method is adequately integrated into the clinical treatment process. To promote an appropriate use of TDM, the TDM expert group of the Arbeitsgemeinschaft für Neuropsychopharmakologie und Pharmakopsychiatrie (AGNP) issued guidelines for TDM in psychiatry in 2004. Since then, knowledge has advanced significantly, and new psychopharmacologic agents have been introduced that are also candidates for TDM. Therefore the TDM consensus guidelines were updated and extended to 128 neuropsychiatric drugs. 4 levels of recommendation for using TDM were defined ranging from "strongly recommended" to "potentially useful". Evidence-based "therapeutic reference ranges" and "dose related reference ranges" were elaborated after an extensive literature search and a structured internal review process. A "laboratory alert level" was introduced, i. e., a plasma level at or above which the laboratory should immediately inform the treating physician. Supportive information such as cytochrome P450 substrate- and inhibitor properties of medications, normal ranges of ratios of concentrations of drug metabolite to parent drug and recommendations for the interpretative services are given. Recommendations when to combine TDM with pharmacogenetic tests are also provided. Following the guidelines will help to improve the outcomes of psychopharmacotherapy of many patients especially in case of pharmacokinetic problems. Thereby, one should never forget that TDM is an interdisciplinary task that sometimes requires the respectful discussion of apparently discrepant data so that, ultimately, the patient can profit from such a joint effort.

Therapeutic drug monitoring in pharmacovigilance and pharmacotherapy safety.

Quantification of serum or plasma concentrations of medications is essential to find out if an adverse drug effect (ADE) is associated with an elevated drug concentration. In former years TDM was therefore often used in pharmacovigilance just to confirm that an ADE that had already occurred was due to an elevated drug plasma concentration without identifying the underlying cause for the surprising high concentration. This old approach of Therapeutic Drug Monitoring (TDM) in pharmacovigilance needs to be revised due to new developments in information technology, new analytical procedures and due to the inclusion of clinical pharmacological expert opinions in the presentation of laboratory medicine results. Today, TDM may be used to prevent ADE, rather than just confirming a suggested cause of an ADE that has happened in the past. This approach means that blood should be drawn for TDM analysis after the pharmacokinetic steady state has been reached (5 times of the elimination half life of the drug) with low to moderate dosages under the intended (poly)medication if the patient is clinically regarded as not belonging to the "normal" patient population. With the availability of reliable automated analytical methods this can be performed at a reasonable price. Funds may be saved to the health care system, because hospitalization will be thereby shortened and expensive diagnoses and treatment of ADE will be avoided. However, this has still to be proven in cross-system studies: Budget will be saved in 2 areas of the health system (hospital stay and drug costs), whereas a much smaller amount of money has to be invested for laboratory analyses in another area. TDM may thus change pharmacovigilance as a tool for monitoring and documentation of ADE to a safety tool in drug therapy for prevention of ADE.

Completed suicides in 47 psychiatric hospitals in Germany--results from the AGATE-study.

INTRODUCTION: There is an ongoing debate about a possibly enhanced risk of suicidal behaviour in some psychiatric patients due to psychopharmacotherapy. Our retrospective study aimed at analyzing the psychopharmacotherapy of 133 inpatient suicides and 133 controls by a matched pair design. METHODS: We analyzed all suicides (n = 133) reported in the AGATE study from 1991 to 2008. Besides evaluation of sociodemographic variables and suicide methods, we compared psychopharmacotherapy of suicides with schizophrenia (n = 59) and affective disorders (n = 59) to that of a matched control group. RESULTS: Most suicides (n = 102, 76.7%) were judged not to be related to psychopharmacotherapy. In general, more psychopharmacological drugs were prescribed for suicides than for controls. Schizophrenic suicides received more low potency FGAs than their controls. More suicides with affective disorders than controls were treated with NASSAs, SNRIs, and high or low potency FGAs. In contrast to their controls, none of the suicides with affective disorders received lithium. NASSAs, SNRIs, and high or low potency FGAs predicted suicide in regression analysis for inpatients with affective disorders. DISCUSSION: Differences in psychopharmacotherapy might mainly result from a recognized risk of suicide or a more severe degree of illness. However, the underrepresentation of lithium in the suicide groups is noticeable.

[Expanding therapeutic reference ranges using dose-related reference ranges]. / Wirkstoffkonzentrationsbestimmungen zur Therapieleitung. Ergänzung therapeutischer Referenzbereiche durch dosisbezogene Referenzbereiche.

Evidence-based therapeutic drug monitoring (TDM), which may be successfully employed to guide drug therapy in clinical routine, supplies all the information from laboratory determination of a drug concentration in a patient's blood specimen. This value is interpreted first of all in relation to a therapeutic reference range that must be established according to the same rules that are generally accepted for clinical studies aimed to license a new drug. The drug concentration may be furthermore interpreted in reference to a dose-related reference range. Thereby a signal is created to alert for individual abnormalities such as drug/drug interactions, gene polymorphisms that give rise to slow/rapid metabolizers, altered function of the excretion organs liver and kidneys by age and/or disease, compliance problems, a missing pharmacokinetic steady state, and even signal overlay in the laboratory analysis. We return all information available and clinical pharmacological comments to physicians who send specimens to our laboratory.