An overview of psychotropic drug-drug interactions

Central Neuromodulators in Irritable Bowel Syndrome: Why, How, and When

Irritable bowel syndrome (IBS) is responsive to treatments using central neuromodulators. Central neuromodulators work by enhancing the synaptic transmission of 5-hydroxytryptamine, noradrenalin, and dopamine, achieving a slower regulation or desensitization of their postsynaptic receptors. Central neuromodulators act on receptors along the brain-gut axis, so they are useful in treating psychiatric comorbidities, modifying gut motility, improving central downregulation of visceral signals, and enhancing neurogenesis in patients with IBS. Choosing a central neuromodulator for treating IBS should be according to the pharmacological properties and predominant symptoms. The first-line treatment for pain management in IBS is using tricyclic antidepressants. An alternative for pain management is the serotonin and noradrenaline reuptake inhibitors. Selective serotonin reuptake inhibitors are useful when symptoms of anxiety and hypervigilance are dominant but are not helpful for treating abdominal pain. The predominant bowel habit is helpful when choosing a neuromodulator to treat IBS; selective serotonin reuptake inhibitors help constipation, not pain, but may cause diarrhea; tricyclic antidepressants help diarrhea but may cause constipation. A clinical response may occur in 6-8 weeks, but long-term treatment (usually 6-12 months) is required after the initial response to prevent relapse. Augmentation therapy may be beneficial when the therapeutic effect of the first agent is incomplete or associated with side effects. It is recommended to reduce the dose of the first agent and add a second complementary treatment. This may include an atypical antipsychotic or brain-gut behavioral treatment. When tapering central neuromodulators, the dose should be reduced slowly over 4 weeks but may take longer when discontinuation effects occur.

High prevalence of potential psychotropic drugs interactions among Brazilian dental patients

OBJECTIVE

To determine the prevalence of potential drug-drug interactions involving psychotropics prescribed by dentists, and dispensed by the public healthcare system, as well as to describe the severity and level of evidence of those interactions in the state of Minas Gerais, Brazil.

MATERIALS AND METHODS

We conducted data analysis from pharmaceutical claims in which dental patients received systemic psychotropics in 2017. Data from the Pharmaceutical Management System provided the drug dispensing history of the patients, allowing the identification of those on concomitant medication use. The outcome was the occurrence of potential drug-drug interactions, which were detected according to IBM Micromedex®. Independent variables were the patient's sex, age, and the number of drugs used. Descriptive statistics was performed using SPSS v. 26.

RESULTS

Overall, 1480 individuals were prescribed psychotropic drugs. The prevalence of potential drug-drug interactions was 24.8% (n = 366). The total of 648 interactions was observed and, most of which were of major severity (n = 438, 67.6%). Most interactions occurred in female individuals (n = 235; 64.2%), with 46.0 (±17.3) years-old, concurrently taking 3.7 (±1.9) drugs.

CONCLUSION

A substantial proportion of dental patients presented potential drug-drug interactions, mostly of major severity, which might be life-threatening.

Drug-drug interactions between COVID-19 drug therapies and antidepressants

INTRODUCTION

Antidepressants are widely used for the pharmacological treatment of anxiety and mood disorders. Since the eruption of the SARS-COV-2 pandemic and the later development of targeted treatments against COVID-19, inevitably many patients receive antidepressants as well as targeted treatments against COVID-19 against COVID-19. Co-administration of antidepressants with COVID-19 therapeutics has the potential of drug-drug interactions, of varying severity and clinical significance.

AREAS COVERED

This is a curated narrative review of the current state of the art regarding drug-drug interactions between COVID-19 therapeutics and medications licensed for the pharmacotherapy of depression. A systematic search of electronic databases, using as keywords the international nonproprietaty names of currently approved COVID-19 therapeutics and antidepressants was performed, and additionally online interaction checker tools were consulted. Derived data were synthesized for each COVID-19 therapeutic and presented with up-to-date guidance.

EXPERT OPINION

Several COVID-19 therapeutics have potential for drug-drug interactions with antidepressants. Remdesivir and Nirmatrelvir-Ritonavir have the higher risk, whereas several monoclonal antibodies appear safer. The most serious drug-drug interactions (serotonin syndrome and QTc prolongation) require close monitoring; however, DDI toward reducing the efficacy of antidepressants may be difficult to recognize. As COVID-19 treatment protocols take precedence, psychiatrists should exert flexibility in antidepressant use and proactively monitor treatment progress.

Potential drug-drug interactions in outpatients with depression of a psychiatry department

Objective

This study aims to explore the prevalence and associated risk factors for potential drug-drug interactions (pDDIs) in prescriptions among outpatients with depression, and report the widespread relevant drug interactions.

Methods

The cross-sectional retrospective study was conducted on outpatients in a psychiatric hospital. We included prescriptions of outpatients with a principal diagnosis of depression from April 1st to June 30th in 2021. The patients were ≥ 18 years old and treated with two or more drugs including at least one psychotropic drug. pDDIs were detected and identified mainly using Medscape's drug interactions checker. Gender, the number of concomitant drugs, age and diagnosis were analysed as potential risk factors for the occurrence of pDDIs by logistic regression.

Results

A total of 13,617 prescriptions were included in the present analysis, and 4222 prescriptions (31.0%) were at risk of 8557 pDDIs. The risk of pDDIs in patients who were prescribed 4-6 drugs (OR: 3.49, 95% CI: 3.11-3.91, p < 0.001) or 7 or more drugs simultaneously (OR: 7.86, 95% CI: 1.58-39.04, p < 0.05) increased compared with patients prescribed 2-3 drugs. Patients with recurrent depressive disorders (OR: 1.18, 95% CI: 1.02-1.36, p < 0.05) had an increased risk of pDDIs compared with patients with depressive episodes. In terms of severity of pDDIs identified by Medscape's drug interactions checker, 0.7%, 16.4%, 77.5% and 5.4% of pDDIs were classified as contraindicated, serious, monitor closely and minor, respectively. The most common pDDI was escitalopram + quetiapine (374 prescriptions), which was classified as serious and monitor closely due to different mechanisms of interaction. Increased central nervous system (CNS)-depressant effect was the most frequent potential clinical adverse outcome of the identified pDDIs.

Conclusions

pDDIs in outpatients with depression were prevalent in this retrospective study. The number of concomitant drugs and severity of the disease were important risk factors for pDDIs. The pDDIs of the category monitor closely were the most common, and the CNS-depressant effect was the most frequent potential clinical adverse outcome.

Enthalpy-Entropy Compensation in the Structure-Dependent Effect of Nonsteroidal Anti-inflammatory Drugs on the Aqueous Solubility of Diltiazem

Certain combinations of acidic and basic drugs can cause significant changes in physicochemical properties through the formation of ionic liquids, eutectic mixtures, or deep eutectic solvents. In particular, combining indomethacin and lidocaine is known to result in apparent increases in both the partition coefficients (hydrophobicity) and aqueous solubilities (hydrophilicity). The physicochemical interactions between drugs change the water solubility of the drugs and affect the bio-availability of active pharmaceutical ingredients. Therefore, we need to clarify the mechanism of changes of water solubility of drugs through the physicochemical interactions. In the present study, we identified a thermodynamic factor that regulates the dissolution of a basic drug, in the presence of various acidic nonsteroidal anti-inflammatory drugs. The results demonstrated that enthalpy-entropy compensation plays a key role in the dissolution of drug mixtures and that relevant thermodynamic conditions should be considered.

The relationship between dose and serotonin transporter occupancy of antidepressants-a systematic review

Brain imaging techniques enable the visualization of serotonin transporter (SERT) occupancy as a measure of the proportion of SERT blocked by an antidepressant at a given dose. We aimed to systematically review the evidence on the relationship between antidepressant dose and SERT occupancy. We searched PubMed and Embase (last search 20 May 2021) for human in vivo, within-subject PET, or SPECT studies measuring SERT occupancy at any dose of any antidepressant with highly selective radioligands ([¹¹C]-DASB, [¹²³I]-ADAM, and [¹¹C]-MADAM). We summarized and visualized the dose-occupancy relationship for antidepressants across studies, overlaying the plots with a curve based on predicted values of a standard 2-parameter Michaelis-Menten model fitted using the observed data. We included seventeen studies of 10 different SSRIs, SNRIs, and serotonin modulators comprising a total of 294 participants, involving 309 unique occupancy measures. Overall, following the Michaelis-Menten equation, SERT occupancy increased with a higher dose in a hyperbolic relationship, with occupancy increasing rapidly at lower doses and reaching a plateau at approximately 80% at the usual minimum recommended dose. All the studies were small, only a few investigated the same antidepressant, dose, and brain region, and few reported information on factors that may influence SERT occupancy. The hyperbolic dose-occupancy relationship may provide mechanistic insight of relevance to the limited clinical benefit of dose-escalation in antidepressant treatment and the potential emergence of withdrawal symptoms. The evidence is limited by non-transparent reporting, lack of standardized methods, small sample sizes, and short treatment duration. Future studies should standardize the imaging and reporting procedures, measure occupancy at lower antidepressant doses, and investigate the moderators of the dose-occupancy relationship.

Potential drug-drug interactions with psychotropic drugs in paediatric inpatients: A cross-sectional study

AIMS

Polypharmacy and drug-drug interactions (DDIs) are important problems that necessitate more attention in paediatric inpatients. This study aimed to determine and evaluate DDIs in paediatric inpatients using psychotropic drugs.

METHODS

It was conducted as a retrospective cross-sectional study. Inpatients consulted by child and adolescent psychiatrists (CAPs) and had at least one psychotropic drug-using between January 2016 and September 2017 were retrospectively included. To determine the clinical significance of DDIs by Micromedex^® and DDI Predictor online databases. DDIs between psychotropic and other drugs, the type, severity, and duration of potential DDIs were evaluated.

RESULTS

During the study period, 564 patients' records were reviewed and 200 patients were considered eligible and included in the study. The median (min-max) age was 13.70 (1.5-17.83) years. The mean (SD) number of psychotropics used during hospitalisation was 1.29 (0.55) and the total number of drugs was 7.39 (4.45). A total of 336 potential DDIs were detected (2.19 DDIs/patient) in all patients. The most common potential outcome of psychotropic DDIs was drug-induced QTc prolongation (67.56%). While 92.85% of the potential DDIs were "contraindicated" or "major," only 18.46% had a "good" or "excellent" strength of evidence. The risk of psychotropic polypharmacy (OR:0.73, 95% CI 0.59-0.92; p:0.006) and DDIs (OR:0.69, 95% CI 0.35-0.76; p:0.033) was significantly higher in patients without primary psychiatric disorders. When the total number of drugs and the total number of potential DDIs were compared amongst all inpatient units, significant differences were found between paediatric hematology-general paediatrics (mean difference: 2.002; P < .001) and paediatric hematology-paediatric ICU (mean difference: 1.650; P = .012), respectively.

CONCLUSION

Psychotropic drug-related DDI is a major problem in the paediatric population and the clinical significance of the potential DDIs' risk should be determined in patient-centred care and managed by the multidisciplinary team.

Clopidogrel drug interactions: a review of the evidence and clinical implications

INTRODUCTION

Patients with cardiovascular disease are commonly affected by a number of comorbidities leading to a high prevalence of polypharmacy. Polypharmacy increases the probability of drug-drug interactions (DDIs). Amongst these, DDIs involving clopidogrel, the most commonly utilized platelet P2Y₁₂ inhibitor, is a topic of potential clinical concern.

AREAS COVERED

This article reviews DDIs between clopidogrel and drugs which are widely used in clinical practice. In particular, drugs shown to interfere with the pharmacodynamic and pharmacokinetic effects of clopidogrel and the clinical implications of these findings are reviewed. These drugs include inhibitors of gastric acid secretion, statins, calcium channel blockers, antidiabetic agents, and antimicrobial agents. For the references, we searched PubMed, EMBASE, or the Cochrane Library.

EXPERT OPINION

Clopidogrel-drug interactions are common. Most of these DDIs are limited to laboratory findings showing an impact on clopidogrel-induced antiplatelet effects. While variability in clopidogrel-induced antiplatelet effects is known to affect clinical outcomes, with high platelet reactivity being associated with thrombotic complications among patients undergoing coronary stenting, most studies assessing the clinical implications of clopidogrel-drug interactions have not shown to significantly affect outcomes. However, awareness of these DDIs remains important for optimizing the selection of concomitant therapies.

Psychotropic polypharmacy and its association with health-related quality of life among cancer survivors in the USA: a population-level analysis

PURPOSE

Cancer survivors that use multiple psychotropic medications are at an increased risk of psychotropic polypharmacy. We examined the association between psychotropic polypharmacy and health-related quality of life (HRQoL) among cancer survivors living in the USA.

METHODS

We used the Medical Expenditure Panel Survey (MEPS) data for 2010, 2012, and 2014 to identify adult cancer survivors. Psychotropic polypharmacy was defined as use of at least two classes of psychotropic prescription medications. The physical component summary (PCS) and the mental component summary (MCS) were obtained from the 12-item Short Form Health Survey version 2 to measure HRQoL. Adjusted ordinary least square regressions were performed to evaluate the association between psychotropic polypharmacy and HRQoL.

RESULTS

Among 31 million US cancer survivors (weighted from a sample of 2609), 16.3% reported psychotropic polypharmacy. Lung cancer survivors had the highest prevalence of psychotropic polypharmacy (22.5%), followed by survivors of breast cancer (17.8%), colorectal, and other gastrointestinal cancers (16.0%). The unadjusted PCS and MCS scores for those with psychotropic polypharmacy were significantly lower than those without psychotropic polypharmacy, overall, and for each cancer type. In multivariable regressions, cancer survivors with psychotropic polypharmacy had significantly lower PCS scores (β =  - 3.63, p < 0.0001) and MCS scores (β =  - 2.28, p = 0.0138) compared to those without psychotropic polypharmacy.

CONCLUSION

Cancer survivors requiring multiple psychotropic medications have poorer quality of life.

Effects of Binary Mixtures and Transpiration on Accumulation of Pharmaceuticals by Spinach

Many pharmaceuticals are present in reclaimed wastewater and effluent-dominated water bodies used to irrigate edible crops. Previous research has shown that plants irrigated with reclaimed wastewater can accumulate pharmaceuticals. However, plant-driven processes that contribute to differences in accumulation among compounds are not well understood. Here, we tested the effects of exposure to mixtures on spinach accumulation and metabolism of four psychoactive pharmaceuticals found in reclaimed wastewater: carbamazepine, fluoxetine, amitriptyline, and lamotrigine. Coexposure of plants to carbamazepine and fluoxetine or amitriptyline decreased accumulation of the toxic carbamazepine metabolite 10,11-epoxycarbamazepine. Furthermore, we tested a simple transpiration-based accumulation model and found that transpiration is a strong predictor for accumulation of the studied compounds. Amitriptyline accumulated to a larger extent than predicted from transpiration alone, and we suggest the possibility that a transporter protein may be involved in its uptake. Our findings highlight the need to consider plant physiology and mixture effects in studying accumulation of polar and ionizable organic contaminants and their metabolites.

Real-World Direct Health Care Costs Associated with Psychotropic Polypharmacy Among Adults with Common Cancer Types in the United States

BACKGROUND

Psychotropic polypharmacy is not uncommon among cancer patients and may contribute to the increased direct health care cost burden in this population.

OBJECTIVE

To estimate average direct health care costs in the year following cancer diagnosis among cancer patients receiving psychotropic polypharmacy compared with those without psychotropic polypharmacy, using a multivariable analysis framework.

METHODS

A retrospective cross-sectional study was conducted among patients aged 18 years and older diagnosed with the most commonly occurring cancers (breast, prostate, lung, and colorectal) in the United States during 2011-2012 using the deidentified Optum Clinformatics Data Mart commercial claims database. Psychotropic polypharmacy was defined as concurrent use of 2 or more psychotropic medications for at least 90 days. Direct health care costs in the year following cancer diagnosis were estimated as total medical payments made by the health plans and were derived from claims files. A generalized linear regression model with log-link function and gamma distribution was used to model average direct health care costs, controlling for baseline patient demographic and clinical covariates.

RESULTS

Average annual direct health care costs for cancer patients with psychotropic polypharmacy ($53,497; SD $72,590) were higher than those without psychotropic polypharmacy ($38,255; SD $59,844), with an unadjusted average cost difference of $15,242 (P < 0.0001). In the adjusted regression model, the average difference in costs shrunk to $5,888 but remained notable. When examined by type of cancer, average direct health care costs for all cancer patients with psychotropic polypharmacy were significantly higher than those for patients without psychotropic polypharmacy, except for colorectal cancer patients.

CONCLUSIONS

Overall health care costs were higher among cancer patients with psychotropic polypharmacy compared with those without psychotropic polypharmacy. Our findings support the need for future research to better understand the benefits and risks of psychotropic polypharmacy, given its potential to cause adverse health outcomes and avoidable health care utilization and costs for this vulnerable patient population.

DISCLOSURES

This study was funded by the American Association of Colleges of Pharmacy (AACP) New Investigator Award mechanism, which was received by Vyas. Aroke was partially supported by the AACP grant for conducting data analysis of the study. Kogut is partially supported by Institutional Development Award Number U54GM115677 from the National Institute of General Medical Sciences of the National Institutes of Health, which funds Advance Clinical and Translational Research (Advance-CTR). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health and the AACP. The authors report no conflicts of interest. An abstract of this study was presented as a poster at the American Association of Colleges of Pharmacy Annual Meeting on July 22, 2018, in Boston, MA.

Prevalence of Psychotropic Polypharmacy and Associated Healthcare Resource Utilization during Initial Phase of Care among Adults with Cancer in USA

BACKGROUND

The use of psychotropic medications is not uncommon among patients with newly diagnosed cancer. However, the impact of psychotropic polypharmacy on healthcare utilization during the initial phase of cancer care is largely unknown.

METHODS

We used a claims database to identify adults with incident breast, prostate, lung, and colorectal cancers diagnosed during 2011-12. Psychotropic polypharmacy was defined as concurrent use of two or more psychotropic medication classes for at least 90 days. A multivariable logistic regression was performed to identify significant predictors of psychotropic polypharmacy. Multivariable Poisson and negative binomial regressions were used to assess the associations between psychotropic polypharmacy and healthcare utilization.

RESULTS

Among 5604 patients included in the study, 52.6% had breast cancer, 30.6% had prostate cancer, 11.4% had colorectal cancer, and 5.5% had lung cancer. During the year following incident cancer diagnosis, psychotropic polypharmacy was reported in 7.4% of patients, with the highest prevalence among patients with lung cancer (14.4%). Compared with patients without psychotropic polypharmacy during the initial phase of care, patients with newly diagnosed cancer with psychotropic polypharmacy had a 30% higher rate of physician office visits, an 18% higher rate of hospitalization, and a 30% higher rate of outpatient visits. The rate of emergency room visits was similar between the two groups.

CONCLUSION

Psychotropic polypharmacy during the initial phase of cancer care was associated with significantly increased healthcare resource utilization, and the proportion of patients receiving psychotropic polypharmacy differed by type of cancer.

IMPACT

Findings emphasize the importance of evidence-based psychotropic prescribing and close surveillance of events causing increased healthcare utilization among patients with cancer receiving psychotropic polypharmacy.

Analysis of smoking behavior on the pharmacokinetics of antidepressants and antipsychotics: evidence for the role of alternative pathways apart from CYP1A2

Smoking is common among psychiatric patients and has been shown to accelerate the metabolism of different drugs. We aimed to determine the effect of smoking on the serum concentrations of psychopharmacological drugs in a naturalistic clinical setting. Dose-corrected, steady-state serum concentrations of individual patients were analyzed retrospectively by linear regression including age, sex, and smoking for amitriptyline (n=503), doxepin (n=198), mirtazapine (n=572), venlafaxine (n=534), clozapine (n=106), quetiapine (n=182), and risperidone (n=136). Serum levels of amitriptyline (P=0.038), clozapine (P=0.02), and mirtazapine (P=0.002) were significantly lower in smokers compared with nonsmokers after correction for age and sex. In addition, the ratios of nortriptyline/amitriptyline (P=0.001) and nordoxepin/doxepin (P=0.014) were significantly higher in smokers compared with nonsmokers. Smoking may not only induce CYP1A2, but may possibly also affect CYP2C19. Furthermore, CYP3A4, UGT1A3, and UGT1A4 might be induced by tobacco smoke. Hence, a different dosing strategy is required among smoking and nonsmoking patients. Nevertheless, the clinical relevance of the results remained unclear.

Establishing a Multidisciplinary Approach to the Management of Neurologic Disease Affecting the Urinary Tract

Neurologic diseases often affect the urinary tract and may be congential or acquired. The progressive nature of many neurologic diseases necessitates routine surveillance and treatment with a multidisciplinary approach. Urologic treatments may interact with pharmacologic or procedural interventions planned by other specialists, mandating close coordination of care and communication among providers. Primary care and nursing often can serve as the quarterbacks of the multidisciplinary team by identifying when a slowly progressive condition warrants further investigation and management by specialists.

Central Neuromodulators for Treating Functional GI Disorders: A Primer

Patients with functional GI disorders (FGIDs) are commonplace in the gastroenterologist's practice. A number of these patients may be refractory to peripherally acting agents, yet respond to central neuromodulators. There are benefits and potential adverse effects to using TCAs, SSRIs, SNRIs, atypical antipsychotics, and miscellaneous central neuromodulators in these patients. These agents can benefit mood, pain, diarrhea, constipation, nausea, sleep, and depression. The mechanisms by which they work, the differences between classes and individual agents, and the various adverse effects are outlined. Dosing, augmentation strategies, and treatment scenarios specifically for painful FGIDs, FD with PDS, and chronic nausea and vomiting syndrome are outlined.

To what extent are psychiatrists aware of the comorbid somatic illnesses of their patients with serious mental illnesses? - a cross-sectional secondary data analysis

Background

Somatic comorbidities are a serious problem in patients with severe mental illnesses. These comorbidities often remain undiagnosed for a long time. In Germany, physicians are not allowed to access patients’ health insurance data and do not have routine access to documentation from other providers of health care. Against this background, the objective of this article was to investigate psychiatrists’ knowledge of relevant somatic comorbidities in their patients with severe mental illnesses.

Methods

Cross-sectional secondary data analysis was performed using primary data from a prospective study evaluating a model of integrated care of patients with serious mental illnesses. The primary data were linked with claims data from health insurers. Patients’ diagnoses were derived on the basis of the ICD-10 and the Anatomical Therapeutic Chemical (ATC) classification system. Diabetes, hypertension, coronary artery disease (CAD), hyperlipidaemia, glaucoma, osteoporosis, polyarthritis and chronic obstructive pulmonary disease (COPD) were selected for evaluation. We compared the number of diagnoses reported in the psychiatrists’ clinical report forms with those in the health insurance data.

Results

The study evaluated records from 1,195 patients with severe mental illnesses. The frequency of documentation of hypertension ranged from 21% in claims data to 4% in psychiatrists’ documentation, for COPD from 12 to 0%, respectively, and for diabetes from 7 to 2%, respectively. The percentage of diagnoses deduced from claims data but not documented by psychiatrists ranged from 68% for diabetes and 83% for hypertension, to 90% for CAD to 98% for COPD.

Conclusions

The majority of psychiatrists participating in the integrated care programme were insufficiently aware of the somatic comorbidities of their patients. We support allowing physicians to access patients’ entire medical records to increase their knowledge of patients’ medical histories and, consequently, to increase the safety and quality of care.

Retrospective use of PBPK modelling to understand a clinical drug-drug interaction between dextromethorphan and GSK1034702

1. In a clinical trial, a strong drug-drug interaction (DDI) was observed between dextromethorphan (DM, the object or victim drug) and GSK1034702 (the precipitant or perpetrator drug), following single and repeat doses. This study determined the inhibition parameters of GSK1034702 in vitro and applied PBPK modelling approaches to simulate the clinical observations and provide mechanistic hypotheses to understand the DDI. 2. In vitro assays were conducted to determine the inhibition parameters of human CYP2D6 by GSK1034702. PBPK models were populated with the in vitro parameters and DDI simulations conducted and compared to the observed data from a clinical study with DM and GSK1034702. 3. GSK1034702 was a potent direct and metabolism-dependent inhibitor of human CYP2D6, with inhibition parameters of: IC₅₀=1.6 μM, K_inact = 3.7 h^-1 and K_I = 0.8 μM. Incorporating these data into PBPK models predicted a DDI after repeat, but not single, 5 mg doses of GSK1034702. 4. The DDI observed with repeat administration of GSK1034702 (5 mg) can be attributed to metabolism-dependent inhibition of CYP2D6. Further, in vitro data were generated and several potential mechanisms proposed to explain the interaction observed following a single dose of GSK1034702.

Frequency and clinical relevance of potential cytochrome P450 drug interactions in a psychiatric patient population - an analysis based on German insurance claims data

BACKGROUND

Numerous drugs used in the treatment of psychiatric disorders are substrates of cytochrome P450 enzymes and are potential candidates for drug-drug interactions (DDIs).

METHODS

Claims data of a German statutory health insurance company from severely mentally ill patients who registered in an integrated care contract from August 2004 to December 2009 were analysed. We measured time periods of concomitant prescription of drugs that have been reported to interact via cytochrome P450, with a focus on drugs acting as strong inhibitors. Such drug-drug exposure (DDE) is an incontrovertible precursor of DDIs. We assessed whether potential DDIs were considered clinically relevant based on the prescribing information of the respective drugs.

RESULTS

Among all 1221 patients, 186 patients (15.2 %; Clopper-Pearson 95 % confidence interval (CI): 13.3-17.4 %) had at least one DDE prescription, and 58 patients (4.8 %; 95 % CI 3.6-6.1) had at least one DDE prescription involving a strong cytochrome P450 inhibitor. In 59 patients, (4.8 %; 95 % CI: 3.7-6.2 %) five or more DDEs were identified, and five or more DDEs with a strong inhibitor were identified in 18 patients (1.5 %; 95 % CI: 0.9-2.3). The rates of DDEs were 0.27 (Garwood 95%CI: 0.25-0.28) per person-year and 0.07 (95 % CI: 0.07-0.08) for strong-inhibitor DDEs. Four of the ten most frequent DDEs were identified as clinically relevant, and seven of the eight most frequent DDEs involving a strong inhibitor were clinically relevant.

CONCLUSIONS

The number of patients with DDEs was not alarmingly high in our sample. Nevertheless, prescription information showed that some prescribed drug combinations could result in serious adverse consequences that are known to weaken or strengthen the effect of the drugs and should therefore be avoided.

Antipsychotic-induced sensitization and tolerance: Behavioral characteristics, developmental impacts, and neurobiological mechanisms

Antipsychotic sensitization and tolerance refer to the increased and decreased drug effects due to past drug use, respectively. Both effects reflect the long-term impacts of antipsychotic treatment on the brain and result from the brain's adaptive response to the foreign property of the drug. In this review, clinical evidence of the behavioral aspect of antipsychotic sensitization and tolerance is selectively reviewed, followed by an overview of preclinical literature that examines these behavioral characteristics and the related pharmacological and nonpharmacological factors. Next, recent work on the developmental impacts of adolescent antipsychotic sensitization and tolerance is presented and recent research that delineates the neurobiological mechanisms of antipsychotic sensitization and tolerance is summarized. A theoretical framework based on "drug learning and memory" principles is proposed to account for the phenomena of antipsychotic sensitization and tolerance. It is maintained that antipsychotic sensitization and tolerance follow basic principles of learning or acquisition ("induction") and memory ("expression"). The induction and expression of both effects reflect the consequences of associative and nonassociative processing and are strongly influenced by various pharmacological, environmental, and behavioral factors. Drug-induced neuroplasticity, such as functional changes of striatal dopamine D2 and prefrontal serotonin (5-HT)2A receptors and their mediated signaling pathways, in principle, is responsible for antipsychotic sensitization and tolerance. Understanding the behavioral characteristics and neurobiological underpinnings of antipsychotic sensitization and tolerance has greatly enhanced our understanding of mechanisms of antipsychotic action, and may have important implications for future drug discovery and clinical practice.

Monitoring of adverse drug reactions in psychiatry outpatient department of a Secondary Care Hospital of Ras Al Khaimah, UAE

BACKGROUND

Adverse drug reactions (ADRs) are a significant cause of morbidity and mortality, resulting in increased healthcare cost. Association of psychotropic medications with ADRs is common. Pharmacovigilance can play a vital role in alerting the healthcare providers from the possible ADRs and thus protecting the patients receiving psychotropic medications.

AIM

To monitor and report the incidence and nature of ADRs in psychiatry outpatient department (OPD).

MATERIALS AND METHODS

A prospective observational study was carried out in the psychiatry OPD. All the patients attending psychiatry outpatient and satisfying the inclusion criteria were monitored for ADRs. The causality, severity and preventability assessment of documented ADRs was done. Chi-square test was done to identify the association between ADRs and sociodemographic, disease and treatment-related variables. Paired Student's t-test was carried out to compare the significance difference in the weight of the patients who reported weight gain to psychotropic medications.

RESULTS

The incidence rate of ADR was found to be 10.2%. A total of 112 ADRs were documented. Weight gain 18 (16.07%) followed by somnolence 8 (7.14%) was the most commonly reported ADR. Atypical antipsychotics 37 (33.0%) were the most common class of psychotropic drugs implicated in ADRs. Escitalopram 16 (14.28%) followed by quetiapine 14 (12.5%) were associated with a maximum number of ADRs. No significant association (P > 0.05) documented between demographic and treatment-related variables with number of ADRs.

CONCLUSION

Study revealed a moderate incidence of ADRs in patients attending the psychiatry OPD. Majority of the ADRs reported during the study were mild in nature and not preventable type.

Common use of dietary supplements for bipolar disorder: a naturalistic, self-reported study

Background

Dietary supplements are taken by about half of Americans. Knowledge of dietary supplement use is important because they may interact with prescription drugs or other supplements, cause adverse reactions including psychiatric symptoms, or contain inherently toxic ingredients or contaminants. This study explores the use of dietary supplements by patients with bipolar disorder in the US.

Methods

Data were obtained from an ongoing, naturalistic study of patients with bipolar disorder who received pharmacological treatment as usual. The patients self-reported their daily mood, sleep, and medications taken, including all drugs prescribed for bipolar disorder or that the patient felt impacted their mood. These included other prescribed drugs, over-the-counter drugs and dietary supplements. Drugs that received premarketing approval from the FDA were not included as dietary supplements. Patient demographics and daily medication use were characterized.

Results

Data were available from 348 patients in the US who returned a mean 249.5 days of data. In addition to prescribed psychiatric drugs, 101 of the 348 patients (29 %) used a dietary supplement for at least 7 days and 69 (20 %) used a supplement long term (for at least 50 % of days). Of the 101 supplement users, 72 (71.3 %) took one supplement daily. The 101 patients tried over 40 different supplements, and the long-term users took 19 different supplements. The most commonly taken supplements for both groups were fish oil, B vitamins, melatonin, and multivitamins. Patients using supplements were more likely to be white (p < 0.001), older (p = 0.009), and ill for more years (p = 0.025).

Conclusions

Many patients with bipolar disorder use dietary supplements in addition to prescribed drugs. Physicians should obtain detailed information about all dietary supplements taken by patients with bipolar disorder.

[Evidence-based choice and antidepressants treatment in psychiatry]

Depression is a severe and usually recurrent mental disorder which leads to a prominent impairment of physical and social functioning, a reduced quality of life of the patients, implies as well an increased morbidity and mortality. Reducing the social-economic depression burden is possible in the optimization of decision-making process of antidepressant choice (including SSRIs and SNRIs) based on the evidence-based risk/benefit ratio and resource saving potential treatment involving target psychosocial interventions and monitoring of long-term treatment adherence.

How the Probability and Potential Clinical Significance of Pharmacokinetically Mediated Drug-Drug Interactions Are Assessed in Drug Development: Desvenlafaxine as an Example

OBJECTIVE

The avoidance of adverse drug-drug interactions (DDIs) is a high priority in terms of both the US Food and Drug Administration (FDA) and the individual prescriber. With this perspective in mind, this article illustrates the process for assessing the risk of a drug (example here being desvenlafaxine) causing or being the victim of DDIs, in accordance with FDA guidance.

DATA SOURCES/STUDY SELECTION

DDI studies for the serotonin-norepinephrine reuptake inhibitor desvenlafaxine conducted by the sponsor and published since 2009 are used as examples of the systematic way that the FDA requires drug developers to assess whether their new drug is either capable of causing clinically meaningful DDIs or being the victim of such DDIs. In total, 8 open-label studies tested the effects of steady-state treatment with desvenlafaxine (50-400 mg/d) on the pharmacokinetics of cytochrome (CYP) 2D6 and/or CYP 3A4 substrate drugs, or the effect of CYP 3A4 inhibition on desvenlafaxine pharmacokinetics. The potential for DDIs mediated by the P-glycoprotein (P-gp) transporter was assessed in in vitro studies using Caco-2 monolayers.

DATA EXTRACTION

Changes in area under the plasma concentration-time curve (AUC; CYP studies) and efflux (P-gp studies) were reviewed for potential DDIs in accordance with FDA criteria.

RESULTS

Desvenlafaxine coadministration had minimal effect on CYP 2D6 and/or 3A4 substrates per FDA criteria. Changes in AUC indicated either no interaction (90% confidence intervals for the ratio of AUC geometric least-squares means [GM] within 80%-125%) or weak inhibition (AUC GM ratio 125% to < 200%). Coadministration with ketoconazole resulted in a weak interaction with desvenlafaxine (AUC GM ratio of 143%). Desvenlafaxine was not a substrate (efflux ratio < 2) or inhibitor (50% inhibitory drug concentration values > 250 μM) of P-gp.

CONCLUSIONS

A 2-step process based on FDA guidance can be used first to determine whether a pharmacokinetically mediated interaction occurs and then to assess the potential clinical significance of the DDI. In the case of the drug tested in this series of studies, the potential for clinically meaningful DDIs mediated by CYP 2D6, CYP 3A4, or P-gp was found to be low.

Subchronic lithium treatment increases the anxiolytic-like effect of mirtazapine on the expression of contextual conditioned fear

Lithium not only has a mood-stabilizing effect but also the augmentation effect of an antidepressant, the mechanism of which remains unclear. Although lithium may augment the effect of mirtazapine, this augmentation has not been confirmed. Using a contextual fear conditioning test in rats, an animal model of anxiety or fear, we examined the effect of subchronic lithium carbonate (in diet) in combination with systemic mirtazapine on the expression of contextual conditioned fear. Mirtazapine (10mg/kg) reduced freezing one day after fear conditioning dose-dependently, whereas the anxiolytic-like effect of mirtazapine (10mg/kg) diminished seven days after fear conditioning. When the interval between fear conditioning and testing was seven days, only the combination of subchronic 0.2% Li2CO3 but not 0.05% Li2CO3 with acute mirtazapine (10mg/kg) reduced freezing significantly. These results indicate that subchronic 0.2% Li2CO3 treatment enhanced the anxiolytic-like effect of systemic mirtazapine. This augmentation therapy might be useful for the treatment of anxiety disorders.

Psychiatric Services

Deinstitutionalization in the 1960s shifted the care of the mentally ill from state-funded institutions to community settings. Unfortunately, funding to support the treatment needs of this population has continued to be minimized, and countless individuals have not received much needed care. This has resulted in a large increase in mentally ill patients surfacing in jails, homeless shelters, and emergency departments. Subsequently, the federal government has begun to prioritize funding to address the mental health needs of our communities. Pharmacists are in a unique position to influence treatment outcomes for patients with mental illnesses, and the current state of health reform provides avenues for the pharmacist to become an essential part of the health care delivery team in numerous ambulatory care clinical settings. The challenges with adherence, medical and psychiatric comorbidities, polypharmacy with psychotropics, potential for life-threatening adverse effects, and the ever-present need for patient education are but a few reasons why pharmacists can be utilized to provide Medication Therapy Management services for these patients.

Reversible dimers of the atypical antipsychotic quetiapine inhibit p-glycoprotein-mediated efflux in vitro with increased binding affinity and in situ at the blood-brain barrier

The multidrug resistance transporter P-glycoprotein (P-gp) is highly expressed in the capillary endothelial cells of the blood-brain barrier (BBB) where it functions to limit the brain penetration of many drugs, including antipsychotic agents used to treat schizophrenia. Therefore, in an effort to inhibit the transporter, we designed dimers of the antipsychotic drug and P-gp substrate quetiapine (QT), linked by variable length tethers. In P-gp overexpressing cells and in human brain capillary endothelial hCMEC/D3 cells, the dimer with the shortest tether length (QT2C2) (1) was the most potent inhibitor showing >80-fold better inhibition of P-gp-mediated transport than monomeric QT. The dimers, which are linked via ester moieties, are designed to revert to the therapeutic monomer once inside the target cells. We demonstrated that the addition of two sterically blocking methyl groups to the linker (QT2C2Me2, 8) increased the half-life of the molecule in plasma 10-fold as compared to the dimer lacking methyl groups (QT2C2, 1), while retaining inhibitory potency for P-gp transport and sensitivity to cellular esterases. Experiments with purified P-gp demonstrated that QT2C2 (1) and QT2C2Me2 (8) interacted with both the H- and R-binding sites of the transporter with binding affinities 20- to 30-fold higher than that of monomeric QT. Using isolated rat brain capillaries, QT2C2Me2 (8) was a more potent inhibitor of P-gp transport than QT. Lastly, we showed that QT2C2Me2 (8) increased the accumulation of the P-gp substrate verapamil in rat brain in situ three times more than QT. Together, these results indicate that the QT dimer QT2C2Me2 (8) strongly inhibited P-gp transport activity in human brain capillary endothelial cells, in rat brain capillaries, and at the BBB in an animal model.

Psychomotor and subjective effects of bilastine, hydroxyzine, and cetirizine, in combination with alcohol: a randomized, double-blind, crossover, and positive-controlled and placebo-controlled Phase I clinical trials

OBJECTIVE

The aim of this study was to compare the effects of concomitant administration of alcohol and bilastine versus alcohol alone on the central nervous system.

METHODS

Twenty-four healthy young volunteers of both sexes participated in a randomized, double-blind, double-dummy, crossover, and positive-controlled and placebo-controlled clinical trials. At 1-week intervals, subjects received six different treatments: (i) placebo; (ii) alcohol 0.8 g/kg alone (ALC); (iii) ALC in combination with: bilastine 20 mg (B20 + A); (iv) bilastine 80 mg (B80 + A); (v) cetirizine 10 mg (CET + A); and (vi) hydroxyzine 25 mg (HYD + A). Psychomotor performance tests (fine motor, finger tapping, nystagmus, critical flicker-fusion frequency, temporal estimation, 'd2' cancellation, and simple reaction time) and subjective self-reports (drunkenness, drowsiness, mental slowness, clumsiness, anger, attentiveness, competence, happiness, hostility, interest, and extroversion) were carried out at baseline and multiple points thereafter.

RESULTS

All active treatments induced a significant psychomotor impairment. The greatest and most lasting impairment was observed with HYD + A followed by B80 + A and CET + A. In contrast, objective measures showed less impairment with B20 + A and ALC, both with a similar magnitude. Self-reports showed a subjective perception of performance impairment in all active treatments.

CONCLUSION

Concomitant administration of bilastine (at therapeutic dose) and alcohol does not produce greater central nervous system depressant effects than ACL alone.

Interactions between valproic acid and quetiapine/olanzapine in the treatment of bipolar disorder and the role of therapeutic drug monitoring

OBJECTIVES

The anticonvulsant valproic acid and the atypical antipsychotics olanzapine and quetiapine provide synergistic mood-stabilising, antidepressant and antipsychotic activities in the treatment of bipolar and schizoaffective disorders. Existing literature shows that pharmacokinetic and pharmacodynamics drug-drug interactions (DDIs) possibly occur with the use of such a combination. Clinical reports of a possible interaction between the drugs leading to an increased risk of adverse drug reactions have also emerged. The main objective of this paper is to review the incidence of DDIs between the anticonvulsant and the antipsychotics, to postulate the possible mechanisms of the interaction and to establish whether certain target populations are at an increased susceptibility to such interactions. The usefulness of therapeutic drug monitoring (TDM) of the antipsychotics to monitor for an interaction was also assessed. A systematic database search was carried out using the search engine provided by PubMed using the following key words: olanzapine, quetiapine, valproic acid, pharmacokinetic drug-drug interaction, bipolar disorder, therapeutic drug monitoring.

KEY FINDINGS

Evidence of a possible clinically relevant DDI between valproic acid and both antipsychotics has been uncovered. A possible mechanism for the interactions has been postulated, and the importance of TDM has been discussed.

SUMMARY

Further research is required to determine whether DDIs occur with the concurrent use of valproic acid and olanzapine or quetiapine, and to investigate the potential of TDM as a clinical tool in improving pharmacotherapy and preventing toxicity.

Characterization of schizophrenia adverse drug interactions through a network approach and drug classification

Antipsychotic drugs are medications commonly for schizophrenia (SCZ) treatment, which include two groups: typical and atypical. SCZ patients have multiple comorbidities, and the coadministration of drugs is quite common. This may result in adverse drug-drug interactions, which are events that occur when the effect of a drug is altered by the coadministration of another drug. Therefore, it is important to provide a comprehensive view of these interactions for further coadministration improvement. Here, we extracted SCZ drugs and their adverse drug interactions from the DrugBank and compiled a SCZ-specific adverse drug interaction network. This network included 28 SCZ drugs, 241 non-SCZs, and 991 interactions. By integrating the Anatomical Therapeutic Chemical (ATC) classification with the network analysis, we characterized those interactions. Our results indicated that SCZ drugs tended to have more adverse drug interactions than other drugs. Furthermore, SCZ typical drugs had significant interactions with drugs of the "alimentary tract and metabolism" category while SCZ atypical drugs had significant interactions with drugs of the categories "nervous system" and "antiinfectives for systemic uses." This study is the first to characterize the adverse drug interactions in the course of SCZ treatment and might provide useful information for the future SCZ treatment.

Drug treatment patterns in bipolar disorder: analysis of long-term self-reported data

Background

The objective of this study is to investigate drug treatment patterns in bipolar disorder using daily data from patients who received treatment as usual.

Methods

Patients self-reported the drugs taken daily for about 6 months. Daily drug use and drug combinations were determined for each patient, both by the specific drugs and by medication class. The drug load was calculated for all drugs taken within a medication class.

Results and discussion

Four hundred fifty patients returned a total of 99,895 days of data (mean 222.0 days). The most frequently taken drugs were mood stabilizers. Of the 450 patients, 353 (78.4%) took a stable drug combination for ≥50% of days. The majority of patients were taking polypharmacy, including 75% of those with a stable combination. Only a small number of drugs were commonly taken within each medication class, but there were a large number of unique drug combinations: 52 by medication class and 231 by specific drugs. Eighty percent of patients with a stable combination were taking three or less drugs daily. Patients without a stable combination took drugs but made frequent changes. Taking more than one drug within a medication class greatly increased the drug load.

To summarize, (1) patients were more likely to take a mood stabilizer than any other drug; (2) although most patients were taking polypharmacy, there were no predominant drug regimens even among those taking a stable combination; and (3) most patients with a stable combination take a relatively small number of drugs daily. The wide variation in drug regimens and numerous possible drug combinations suggest that more evidence is needed to optimize treatment of bipolar disorder.

Selegiline Transdermal System: An Examination of the Potential for CYP450-Dependent Pharmacokinetic Interactions With 3 Psychotropic Medications

Selegiline transdermal system (STS) is a recently approved monoamine oxidase inhibitor antidepressant. This article reports results from 3 studies examining the potential for cytochrome P450-dependent pharmacokinetic interactions between STS and 3 psychotropic medications that might be coadministered. Three open-label, randomized, Latin square, 3-sequence crossover design studies were conducted with healthy volunteers to determine the pharmacokinetic parameters of STS 6 mg/24 h and test drug (alprazolam, olanzapine, or risperidone) when administered alone and concomitantly. All pharmacokinetic parameters of interest were unaltered following selegiline or test drug monotherapy when compared to concomitant therapy. This was confirmed by least squares mean ratios and their 90% confidence intervals of log(e)-transformed C(max) and AUC(tau) values, using either standard bioequivalence criteria of 80% to 125% or study-defined 70% to 143% boundary criteria. These results demonstrate that STS 6 mg/24 h may provide an antidepressant option that is unlikely to result in CYP450-mediated pharmacokinetic drug-drug interactions.

Investigation of drug-drug interactions between clopidogrel and fluoxetine

Drug-drug interactions may contribute to the variability of the response of clopidogrel. Several hypotheses have been proposed concerning the potential modification of clopidogrel pharmacokinetics and pharmacodynamics by fluoxetine. This open-label crossover study assessed the effect of fluoxetine on the pharmacological activity of clopidogrel in healthy volunteers. Eight healthy male volunteers received a single 600-mg loading dose of clopidogrel followed by 20 mg of fluoxetine on 4 days and then 20 mg of fluoxetine plus 600 mg of clopidogrel on the fifth day. Eleven blood samples were withdrawn after clopidogrel administration to determine plasma concentrations of clopidogrel active metabolite (CAM) and platelet function. Platelet aggregation was measured by light transmittance aggregometry (LTA) and platelet reactivity index by flow cytometric vasodilator-stimulated phosphoprotein (VASP) analysis. The areas under the curve and maximum plasma concentrations of CAM were, respectively, 20.6 and 25.3% lower after co-administration of fluoxetine compared with administration of clopidogrel alone. The percentage maximum platelet aggregation values in the presence of 5 μM and 10 μM adenosine diphosphate, measured by LTA, were, respectively, 13.9 and 22.4% lower after fluoxetine co-administration. The platelet reactivity index measured by the flow cytometric VASP method was 36.8% lower when clopidogrel was administered in conjunction with fluoxetine.

Drug-drug conditioning between citalopram and haloperidol or olanzapine in a conditioned avoidance response model: implications for polypharmacy in schizophrenia

Patients with schizophrenia often have anxiety and depression, and thus are treated with multiple psychotherapeutic medications. This practice of polypharmacy increases the possibility for drug-drug interactions. However, the pharmacological and behavioral mechanisms underlying drug-drug interactions in schizophrenia remain poorly understood. In the present study, we adopted a preclinical approach and examined a less known behavioral mechanism, drug-drug conditioning (DDC) between haloperidol (a typical antipsychotic) or olanzapine (atypical antipsychotic) and citalopram (a selective serotonin reuptake inhibitor). A rat two-way conditioned avoidance response paradigm was used to measure antipsychotic activity and determine how DDC may alter the antipsychotic efficacy in this model. Following acquisition of the avoidance response, rats were then randomly assigned to receive vehicle, citalopram (10.0 mg/kg, intraperitoneally), haloperidol (0.05 mg/kg, subcutaneously), olanzapine (1.0 mg/kg, subcutaneously), combined haloperidol with citalopram, or combined olanzapine with citalopram treatment for seven avoidance test sessions. In comparison with antipsychotic treatment alone, combined treatment with citalopram potentiated the antiavoidance effect of olanzapine or haloperidol (to a lesser extent) during the seven drug-test sessions. In addition, repeated pairing of citalopram with haloperidol or olanzapine caused citalopram to show a newly acquired avoidance-disruptive effect. This effect was context specific because citalopram paired with haloperidol or olanzapine outside the avoidance testing context (i.e. home cages) did not show such an effect. These findings indicate that concurrent antidepressant and antipsychotic treatments may engender a DDC process that follows the general Pavlovian associative conditioning principles. They also indicate that adjunctive citalopram treatment may enhance the antipsychotic efficacy of haloperidol and olanzapine in the treatment of schizophrenia.

Psychotropic drug-drug interactions involving P-glycoprotein

Multidrug resistance P-glycoprotein (P-gp; also known as MDR1 and ABCB1) is expressed in the luminal membrane of the small intestine and blood-brain barrier, and the apical membranes of excretory cells such as hepatocytes and kidney proximal tubule epithelia. P-gp regulates the absorption and elimination of a wide range of compounds, such as digoxin, paclitaxel, HIV protease inhibitors and psychotropic drugs. Its substrate specificity is as broad as that of cytochrome P450 (CYP) 3A4, which encompasses up to 50 % of the currently marketed drugs. There has been considerable interest in variations in the ABCB1 gene as predictors of the pharmacokinetics and/or treatment outcomes of several drug classes, including antidepressants and antipsychotics. Moreover, P-gp-mediated transport activity is saturable, and is subject to modulation by inhibition and induction, which can affect the pharmacokinetics, efficacy or safety of P-gp substrates. In addition, many of the P-gp substrates overlap with CYP3A4 substrates, and several psychotropic drugs that are P-gp substrates are also CYP3A4 substrates. Therefore, psychotropic drugs that are P-gp substrates may cause a drug interaction when P-gp inhibitors and inducers are coadministered, or when psychotropic drugs or other medicines that are P-gp substrates are added to a prescription. Hence, it is clinically important to accumulate data about drug interactions through studies on P-gp, in addition to CYP3A4, to assist in the selection of appropriate psychotropic medications and in avoiding inappropriate combinations of therapeutic agents. There is currently insufficient information available on the psychotropic drug interactions related to P-gp, and therefore we summarize the recent clinical data in this review.

Clinically significant psychotropic drug-drug interactions in the primary care setting

In recent years, the growing numbers of patients seeking care for a wide range of psychiatric illnesses in the primary care setting has resulted in an increase in the number of psychotropic medications prescribed. Along with the increased utilization of psychotropic medications, considerable variability is noted in the prescribing patterns of primary care providers and psychiatrists. Because psychiatric patients also suffer from a number of additional medical comorbidities, the increased utilization of psychotropic medications presents an elevated risk of clinically significant drug interactions in these patients. While life-threatening drug interactions are rare, clinically significant drug interactions impacting drug response or appearance of serious adverse drug reactions have been documented and can impact long-term outcomes. Additionally, the impact of genetic variability on the psychotropic drug's pharmacodynamics and/or pharmacokinetics may further complicate drug therapy. Increased awareness of clinically relevant psychotropic drug interactions can aid clinicians to achieve optimal therapeutic outcomes in patients in the primary care setting.

Evidence-Based Treatment of Depression in Patients With Cancer

Purpose

Depression is a common condition in patients with cancer, although there has been a relative paucity of research on the effectiveness of treatment in this population. This review summarizes the psychosocial and pharmacologic treatment of depression in patients with cancer based on a consideration of evidence regarding etiologic factors and treatment outcomes.

Methods

A review of the evidence base for psychosocial and pharmacologic interventions for depression in patients with cancer was performed, including original studies, systematic reviews, and meta-analytic studies in the literature.

Results

Recent evidence from randomized controlled trials has demonstrated the efficacy of psychosocial and pharmacologic treatments to alleviate depression in patients with cancer. Further research is needed to establish their relative and combined efficacy and their role in the treatment of depression that is less severe and occurs in association with more advanced disease. First-line recommendations for the treatment of depression in patients with cancer are difficult to derive based on current evidence, because comparative studies have not been conducted to support the superiority of one treatment modality over another in this population.

Conclusion

Both psychosocial and pharmacologic interventions have been shown to be efficacious in treating depression in cancer, but further research is needed to establish their relative and combined benefit. Future research directions include the development and evaluation of novel interventions targeted to specific biologic and psychosocial risk factors.

Age-related changes in antidepressant pharmacokinetics and potential drug-drug interactions: a comparison of evidence-based literature and package insert information

BACKGROUND

Antidepressants are among the most commonly prescribed psychotropic agents for older patients. Little is known about the best source of pharmacotherapy information to consult about key factors necessary to safely prescribe these medications to older patients.

OBJECTIVE

The objective of this study was to synthesize and contrast information in the package insert (PI) with information found in the scientific literature about age-related changes of antidepressants in systemic clearance and potential pharmacokinetic drug-drug interactions (DDIs).

METHODS

A comprehensive search of two databases (MEDLINE and EMBASE from January 1, 1975 to September 30, 2011) with the use of a combination of search terms (antidepressants, pharmacokinetics, and drug interactions) was conducted to identify relevant English language articles. This information was independently reviewed by two researchers and synthesized into tables. These same two researchers examined the most up-to-date PIs for the 26 agents available at the time of the study to abstract quantitative information about age-related decline in systemic clearance and potential DDIs. The agreement between the two information sources was tested with κ statistics.

RESULTS

The literature reported age-related clearance changes for 13 antidepressants, whereas the PIs only had evidence about 4 antidepressants (κ < 0.4). Similarly, the literature identified 45 medications that could potentially interact with a specific antidepressant, whereas the PIs only provided evidence about 12 potential medication-antidepressant DDIs (κ < 0.4).

CONCLUSION

The evidence-based literature compared with PIs is the most complete pharmacotherapy information source about both age-related clearance changes and pharmacokinetic DDIs with antidepressants. Future rigorously designed observational studies are needed to examine the combined risk of antidepressants with age-related decline in clearance and potential DDIs on important health outcomes such as falls and fractures in older patients.

Electronic database to detect drug-drug interactions between antidepressants and oral anticancer drugs from a cancer center in Singapore: implications to clinicians

BACKGROUND

Electronic drug interaction databases are often utilized in clinical practice to detect for possible drug-drug interactions between drug pairs. It is uncertain, however, whether most of these detections interactions are clinically important in practice. To demonstrate these issues, this study utilized a comprehensive drug-drug interaction (DDI) electronic database to elucidate the prevalence of DDIs at a cancer centre between antidepressants and oral anticancer drugs (ACDs).

METHODS

Drug utilization reports were retrieved to determine the patients who were prescribed with antidepressants oral ACDs between 2006 and 2009 at a cancer center. Medication records of these patients were retrospectively examined using OncoRx, an internet-based oncology-specific database that allows the identification of DDIs.

RESULTS

Out of 910 users of antidepressants, about one-third (281 patients, 30.9%) used an oral ACD and an antidepressant concomitantly. From these patients, about one-fifth (21.0%) had potential DDIs. These patients were users of 17 potentially interacting drug pairs. Ten out of the 17 drug pairs could potentially cause pharmacokinetic interactions, and the rest were pharmacodynamic interactions, with only three out of the 17 drug pairs were clinically documented to cause interacting events.

CONCLUSION

The lack of screening conditions may have led to an over detection of DDI combinations by electronic DDI databases. Many of the detected interactions may not deem high significance in clinical practice. This study exposed a major weakness of current electronic DDI databases for detecting oral ACDs and antidepressants DDIs.

Selective serotonin reuptake inhibitor antidepressants potentiate methylphenidate (Ritalin)-induced gene regulation in the adolescent striatum

The psychostimulant methylphenidate (Ritalin) is used in conjunction with selective serotonin reuptake inhibitors (SSRIs) in the treatment of medical conditions such as attention-deficit hyperactivity disorder with anxiety/depression comorbidity and major depression. Co-exposure also occurs in patients on SSRIs who use psychostimulant 'cognitive enhancers'. Methylphenidate is a dopamine/norepinephrine reuptake inhibitor that produces altered gene expression in the forebrain; these effects partly mimic gene regulation by cocaine (dopamine/norepinephrine/serotonin reuptake inhibitor). We investigated whether the addition of SSRIs (fluoxetine or citalopram; 5 mg/kg) modified gene regulation by methylphenidate (2-5 mg/kg) in the striatum and cortex of adolescent rats. Our results show that SSRIs potentiate methylphenidate-induced expression of the transcription factor genes zif268 and c-fos in the striatum, rendering these molecular changes more cocaine-like. Present throughout most of the striatum, this potentiation was most robust in its sensorimotor parts. The methylphenidate + SSRI combination also enhanced behavioral stereotypies, consistent with dysfunction in sensorimotor striatal circuits. In so far as such gene regulation is implicated in psychostimulant addiction, our findings suggest that SSRIs may enhance the addiction potential of methylphenidate.