Antidepressant Drug-Drug Interaction Profile Update

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.

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.

Antidepressants and the risk of hyponatremia: a Danish register-based population study

OBJECTIVE

To examine the association between classes of antidepressants and hyponatremia, and between specific antidepressants and hyponatremia.

DESIGN

Retrospective register-based cohort study using nationwide registers from 1998 to 2012.

SETTING

The North Denmark Region.

PARTICIPANTS

In total, 638 352 individuals were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

Plasma sodium was obtained from the LABKA database. The primary outcome was hyponatremia defined as plasma sodium (p-sodium) below 135 mmol/L and secondary outcome was severe hyponatremia defined as p-sodium below 130 mmol/L. The association between use of specific antidepressants and hyponatremia was analysed using multivariable Poisson regression models.

RESULTS

An event of hyponatremia occurred in 72 509 individuals and 11.36% (n=6476) of these events happened during treatment with antidepressants. Incidence rate ratios and CIs for the association with hyponatremia in the first p-sodium measured after initiation of treatment were for citalopram 7.8 (CI 7.42 to 8.20); clomipramine 4.93 (CI 2.72 to 8.94); duloxetine 2.05 (CI 1.44 to 292); venlafaxine 2.90 (CI 2.43 to 3.46); mirtazapine 2.95 (CI 2.71 to 3.21); and mianserin 0.90 (CI 0.71 to 1.14).

CONCLUSIONS

All antidepressants except mianserin are associated with hyponatremia. The association is strongest with citalopram and lowest with duloxetine, venlafaxine and mirtazapine.

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.

Drug interactions in palliative care--it's more than cytochrome P450

OBJECTIVE

This study aims to identify the combination of substances with high potential for drug interactions in a palliative care setting and to provide concise recommendations for physicians.

METHODS

We used a retrospective systematic chart analysis of 200 consecutive inpatients. The recently developed and internationally advocated classification system OpeRational ClAssification of Drug Interactions was applied using the national database of the Federal Union of German Associations of Pharmacists. Charts of patients with potential for severe DDIs were examined manually for clinical relevance.

RESULTS

In 151 patients (75%) a total of 631 potential drug interactions were identified. Opioids (exception: methadone), non-opioids (exception: non-steroidal anti-inflammatory drugs), benzodiazepines, proton-pump inhibitors, laxatives, co-analgesics (exception: carbamazepine) and butylscopolamine were generally safe. High potential for drug interactions included combinations of scopolamine, neuroleptics, metoclopramide, antihistamines, non-steroidal anti-inflammatory drugs, (levo-) methadone, amitriptyline, carbamazepine and diuretics. The manual analyses of records from eight patients with risk for severe drug interactions provided no indicator for clinical relevance in these specific patients. Drug interactions attributed to the cytochrome pathway played a minor role (exception: carbamazepine).

CONCLUSION

Most relevant drug interactions can be expected with: (i) drugs (inter-) acting via histamine, acetylcholine or dopamine receptors; and (ii) Non-steroidal anti-inflammatory drugs. Even in last hours of life the combination of substances (e.g. anticholinergics) may produce relevant drug interactions (e.g. delirium).

PERSPECTIVE

Data on the potential for drug-drug interactions in palliative case is extremely scarce, but drug interactions can be limited if a few facts are considered. A synopsis of the findings of these studies is presented as concise recommendation to minimize drug interactions.

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.

Multimorbidity and depression treatment

OBJECTIVES

We compare treatment for depression among individuals with multiple chronic physical conditions to those with single chronic physical condition, after controlling for demographic, socioeconomic, access to care and the number of outpatient visits.

METHODS

Using a cross-sectional study design, we analyzed data on 1,376 adults age above 21 years, with depression and at least one chronic physical condition in the following clusters: cardiometabolic (diabetes or heart disease or hypertension), respiratory (chronic obstructive pulmonary disease or asthma) and musculoskeletal (arthritis or osteoporosis) from the 2007 Medical Expenditure Panel Survey for depression treatment.

RESULTS

Overall, 56.2% used antidepressants, 21.4% had psychotherapy and 22.5% reported no depression treatment. After adjusting for factors, there were no statistically significant differences in the likelihood of type of depression treatment.

CONCLUSION

Individuals with multiple conditions are as likely as those with single condition to report treatment for depression perhaps due to increased contact with the health care system. Our findings suggest that competing demands due to multiple chronic conditions may not affect depression treatment.

CYP1A2 genetic polymorphisms are associated with treatment response to the antidepressant paroxetine

AIM

Paroxetine is a drug of choice in the treatment of major depressive disorder (MDD). Its metabolism has recently been reported to be mediated through the CYP enzymes 1A2 and 2D6. In our current study, we tested whether genetic polymorphisms in CYP1A2 are associated with the treatment efficacy and side effects of paroxetine.

MATERIALS & METHODS

A total of 241 MDD patients who had taken paroxetine continually for 8 weeks were recruited, and their steady state paroxetine concentrations were measured at weeks 2, 4 and 8. The genotypes of these patients were then assessed for the presence of nine SNPs, which were selected from either the HapMap Chinese ethnic group, the literature report or through their functional role in the CYP1A2 gene.

RESULTS

The allele types for SNPs rs4646425 (permutation p = 0.03), rs2472304 (permutation p = 0.01) and rs2470890 (permutation p = 0.004) demonstrated significant associations with paroxetine treatment remission at week 8. Response rates in the Hamilton Rating Scale for Depression (HAM-D) and for The Hamilton Rating Scale for Anxiety (HAM-A) were significantly associated with the SNPs rs4646425 (p = 0.0126 and 0.0088 for HAM-D and HAM-A, respectively) and rs4646427 (p = 0.0067 and 0.0196 for HAM-D and HAM-A, respectively). The inducible SNP rs762551 had a significant association with paroxetine dose at week 4 (permutation p = 0.012). We did not find an association between these SNPs and the side effects or serum concentrations of paroxetine.

CONCLUSION

Genetic variants in the CYP1A2 region may be indicators of treatment response in MDD patients to paroxetine.

Clinical utility of desvenlafaxine 50 mg/d for treating MDD: a review of two randomized placebo-controlled trials for the practicing physician

BACKGROUND

Major depressive disorder (MDD) is a common, seriously impairing illness. Desvenlafaxine (administered as desvenlafaxine succinate) is the third serotonin-norepinephrine reuptake inhibitor (SNRI) approved in the United States for the treatment of MDD. Short-term clinical studies have demonstrated the efficacy and safety of 50 to 400 mg/d doses, with no evidence that doses greater than 50 mg/d confer additional benefit.

OBJECTIVE

This paper summarizes published data on the efficacy, safety, and tolerability of the desvenlafaxine 50-mg/d recommended therapeutic dose for MDD and discusses clinical practice considerations.

METHODS

A systematic review of MEDLINE, PsycINFO, and PubMed (all years through June 2009) was performed using the terms desvenlafaxine, DVS, and ODV. The criteria for inclusion in the review were a double-blind design, a placebo control or active comparator group, the 50-mg desvenlafaxine dose group, and enrollment of patients with a diagnosis of MDD. Posters were included if they reported on a study that was subsequently published in a manuscript.

RESULTS

Overall results of two randomized, placebo-controlled, 8-week clinical trials demonstrated the efficacy of desvenlafaxine 50 mg/d for MDD. Statistically significant improvements compared with placebo were observed on the primary efficacy measure (17-item Hamilton Rating Scale for Depression [HAM-D(17)] total score; P < 0.05). Significant differences were observed on several secondary measures (Montgomery Asberg Depression Rating Scale scores in both trials [P < 0.05]; Clinical Global Impressions-Improvement scores [P < or = 0.01], Clinical Global Impressions-Severity scores [P < or = 0.01], HAM-D(17) response [P < or = 0.01] and remission [P < 0.05] in one trial each). Functional outcomes measures (Sheehan Disability Scale total and World Health Organization 5-Item Well-Being Index scores) were significant in both trials (P < 0.05). Safety results indicate desvenlafaxine treatment was safe and well tolerated; findings were consistent with the SNRI class. The generalizability of these findings is limited by the study protocols, which excluded patients with unstable comorbid medical conditions and also those with other Axis 1 and 2 psychiatric illnesses. Additionally, comparisons with other SNRIs are challenging given differences in study design. Desvenlafaxine can be initiated with the 50-mg/d therapeutic dose without titration and provides efficacy with rates of discontinuation due to treatment-emergent adverse events similar to placebo. In vitro data indicate desvenlafaxine has minimal inhibitory effects on cytochrome P450 (CYP) 2D6 and clinical studies show desvenlafaxine does not have a clinically relevant effect on CYP2D6 metabolism. In vitro data also indicate desvenlafaxine is not a substrate or inhibitor of the p-glycoprotein transporter. Plasma protein binding of desvenlafaxine is low (30%) and independent of drug concentration. Bioavailability is high at 80% after oral administration and is not affected by food.

CONCLUSIONS

Desvenlafaxine 50 mg/d has demonstrated efficacy, safety, and tolerability for the treatment of MDD in two placebo-controlled trials. The metabolic profile of desvenlafaxine suggests a low risk of drug-drug interactions owing to minimal inhibitory effects on CYP2D6, lack of interaction with p-glycoprotein, and low protein binding.

Factors impacting the selection of antidepressant treatment in patients with major depressive disorder at risk for nonadherence

Treatment with the newer generation antidepressants is considered generally effective for most patients with major depressive disorder when taken in accordance with treatment guidelines. However, multiple clinical studies have demonstrated that rates of patient adherence to antidepressants are inadequate, specifically with regard to long-term maintenance treatment. Tolerability issues associated with antidepressants can increase the risk for patient nonadherence and result in subsequent relapse of depressive symptoms. Comorbid symptoms of anxiety also influence psychiatrists' choice of antidepressants for patients with depression. Physicians can improve long-term patient outcomes for patients with major depressive disorder by considering the possibility of drug-drug interactions before prescribing a specific antidepressant.

Canadian Network for Mood and Anxiety Treatments (CANMAT) clinical guidelines for the management of major depressive disorder in adults. III. Pharmacotherapy

BACKGROUND

In 2001, the Canadian Psychiatric Association and the Canadian Network for Mood and Anxiety Treatments (CANMAT) partnered to produce evidence-based clinical guidelines for the treatment of depressive disorders. A revision of these guidelines was undertaken by CANMAT in 2008-2009 to reflect advances in the field.

METHODS

The CANMAT guidelines are based on a question-answer format to enhance accessibility to clinicians. An evidence-based format was used with updated systematic reviews of the literature and recommendations were graded according to Level of Evidence using pre-defined criteria. Lines of Treatment were identified based on criteria that included Levels of Evidence and expert clinical support. This section on "Pharmacotherapy" is one of 5 guideline articles.

RESULTS

Despite emerging data on efficacy and tolerability differences amongst newer antidepressants, variability in patient response precludes identification of specific first choice medications for all patients. All second-generation antidepressants have Level 1 evidence to support efficacy and tolerability and most are considered first-line treatments for MDD. First-generation tricyclic and monoamine oxidase inhibitor antidepressants are not the focus of these guidelines but generally are considered second- or third-line treatments. For inadequate or incomplete response, there is Level 1 evidence for switching strategies and for add-on strategies including lithium and atypical antipsychotics.

LIMITATIONS

Most of the evidence is based on trials for registration and may not reflect real-world effectiveness.

CONCLUSIONS

Second-generation antidepressants are safe, effective and well tolerated treatments for MDD in adults. Evidence-based switching and add-on strategies can be used to optimize response in MDD that is inadequately responsive to monotherapy.

How and why study designs affect the nature and validity of study results: appearance versus true knowledge. Part I

Patients often do not respond optimally to the first medication tried so that switching among classes of medications--and even within a class--for a given indication is a common clinical practice. In the absence of data, such switches are often based on clinical judgment or experience, but when data are available, that is generally considered preferable. However, such data may be derived from sub-optimally designed trials that produce only the appearance of knowledge. In this first of a two-part series, findings from sequential treatment trials of selective serotonin reuptake inhibitors (SSRIs) are used to illustrate how such research is done and factors that can affect outcomes. Results of early trials suggested that 50%-60% of patients who did not benefit from one SSRI could benefit when switched to a second SSRI, a finding not supported by pharmacologic data nor recent research. Differences between treatment in clinical trials and routine practice that may account for discrepancies between those early results and pharmacologic data are discussed. Part II of this series will describe study designs, from the least to the most rigorous, to help clinicians recognize when studies are providing the appearance rather than the substance of knowledge.

Clinically important drug interactions potentially involving mechanism-based inhibition of cytochrome P450 3A4 and the role of therapeutic drug monitoring

Cytochrome P450 (CYP) 3A4 is the most abundant enzyme of CYPs in the liver and gut that metabolizes approximately 50% currently available drugs. A number of important drugs have been identified as substrates, inducers, and/or inhibitors of CYP3A4. The substrates of CYP3A4 considerably overlap with those of P-glycoprotein. Both CYP3A4 and P-glycoprotein are subject to inhibition and induction by a number of factors. Mechanism-based inhibition of CYP3A4 is characterized by NADPH-, time-, and concentration-dependent enzyme inactivation occurring when some xenobiotics or drugs are converted by CYPs to reactive metabolites. Such an inhibition of CYP3A4 is caused by chemical modification of the heme, the protein, or both as a result of covalent binding of modified heme to the protein. To date, the identified clinically important mechanism-based CYP3A4 inhibitors mainly include macrolide antibiotics (eg, clarithromycin and erythromycin), anti-HIV agents (eg, ritonavir and delavirdine), antidepressants (eg, fluoxetine and fluvoxamine), calcium channel blockers (eg, verapamil and diltiazem), steroids and their modulators (eg, gestodene and mifepristone), and several herbal and dietary components. The inactivation of CYP3A4 by drugs often causes unfavorable and long-lasting drug-drug interactions and probably fatal toxicity, depending on many factors associated with the enzyme, drugs, and the patients. Clinicians are encouraged to have a sound knowledge of drug-induced, mechanism-based CYP3A4 inhibition; take proper cautions, and perform close monitoring for possible drug interactions when using drugs that are mechanism-based CYP3A4 inhibitors. To minimize drug-drug interactions involving mechanism-based CYP3A4 inhibition, it is necessary to choose safe drug combination regimens, adjust drug dosages appropriately, and conduct therapeutic drug monitoring for drugs with narrow therapeutic indices.

Antidepressants for the treatment of chronic pain

Chronic pain represents one of the most important public health problems and, in addition to classical analgesics, antidepressants are an essential part of the therapeutic strategy. This article reviews available evidence on the efficacy and safety of antidepressants in major chronic pain conditions; namely, neuropathic pain, headaches, low back pain, fibromyalgia, irritable bowel syndrome (IBS) and cancer pain. Studies, reviews and meta-analyses published from 1991 to March 2008 were retrieved through MEDLINE, PsycINFO and the Cochrane database using numerous key words for pain and antidepressants. In summary, evidence supports the use of tricyclic antidepressants in neuropathic pain, headaches, low back pain, fibromyalgia and IBS. The efficacy of the newer serotonin and norepinephrine reuptake inhibitors is less supported by evidence, but can be recommended in neuropathic pain, migraines and fibromyalgia. To date, evidence does not support an analgesic effect of serotonin reuptake inhibitors, but beneficial effects on well-being were reported in several chronic pain conditions. These results are discussed in the light of current insights in the neurobiology of pain, the reciprocal relationship between pain and depression, and future developments in this field of research.