Pharmacological and clinical profile of newer antidepressants: implications for the treatment of elderly patients

A Proposed Algorithm for the Pharmacological Treatment of Generalized Anxiety Disorder in the Older Patient

BACKGROUND

This is a new algorithm from the Psychopharmacology Algorithm Project at the Harvard South Shore Program, focused on generalized anxiety disorder (GAD) in older adults. Pertinent articles were identified and reviewed.

RESULTS

Selective serotonin reuptake inhibitors (SSRIs) are considered to be first-line medications, with a preference for sertraline or escitalopram. If avoiding sexual side effects is a priority, buspirone is an option for the relatively healthy older adult. If response is inadequate, the second recommended trial is with a different SSRI or one of the serotonin-norepinephrine update inhibitors (SNRIs), venlafaxine or duloxetine. For a third medication trial, additional alternatives added to the previous options now include pregabalin/gabapentin, lavender oil, and agomelatine. If there is an unsatisfactory response to the third option chosen, quetiapine may be considered. We recommend caution with the following for acute treatment in this population: benzodiazepines and hydroxyzine. Other agents given low priority but having some supportive evidence were vilazodone, vortioxetine, mirtazapine, and cannabidiol. Acknowledging that the median age of onset of GAD is in early adulthood, many patients with GAD will have been started on benzodiazepines (or other medications that require caution in the elderly) for GAD at a younger age. These medications may be continued with regular observation to see if the potential harms are starting to exceed the benefits and a switch to other recommended agents may be justified.

Population pharmacokinetics model for escitalopram in Chinese psychiatric patients: effect of CYP2C19 and age

Objective: To establish a population pharmacokinetic model in Chinese psychiatric patients to characterize escitalopram pharmacokinetic profile to identify factors influencing drug exposure, and through simulation to compare the results with the established therapeutic reference range.

Methods: Demographic information, dosing regimen, CYP2C19 genotype, concomitant medications, and liver and kidney function indicators were retrospectively collected for inpatients taking escitalopram with therapeutic drug monitoring from 2018 to 2021. Nonlinear mixed-effects modeling was used to model the pharmacokinetic characteristics of escitalopram. Goodness-of-fit plots, bootstrapping, and normalized prediction distribution errors were used to evaluate the model. Simulation for different dosing regimens was based on the final estimations.

Results: The study comprised 106 patients and 337 measurements of serum sample. A structural model with one compartment with first-order absorption and elimination described the data adequately. The population-estimated apparent volume of distribution and apparent clearance were 815 and 16.3 L/h, respectively. Age and CYP2C19 phenotype had a significant effect on the apparent clearance (CL/F). CL/F of escitalopram decreased with increased age, and CL/F of poor metabolizer patients was significantly lower than in extensive and immediate metabolizer patients. The final model-based simulation showed that the daily dose of adolescents with poor metabolizer might be as high as 15 mg or 20 mg and referring to the therapeutic range for adults may result in overdose and a high risk of adverse effects in older patients.

Conclusion: A population pharmacokinetics model of escitalopram was successfully created for the Chinese population. Depending on the age of the patients, CYP2C19 genotype and serum drug concentrations throughout treatment are required for adequate individualization of dosing regimens. When developing a regimen for older patients, especially those who are poor metabolizers, vigilance is required.

Broad spectrum micronutrient formulas for the treatment of symptoms of depression, stress, and/or anxiety: a systematic review

Introduction: Vitamin and mineral nutritional supplements are becoming increasingly popular as alternative treatments for anxiety and depression, as issues such as side effects from medication, failure to respond to psychotherapy and workforce limitations pose barriers for successful treatment.Areas covered: This review covered double-blind, randomized controlled trials (DBRCTs) testing formulas including at least four vitamins and/or minerals used for the treatment of symptoms of anxiety, stress, or depression in adults not currently taking medication for psychiatric difficulties.Expert opinion: The majority of the 23 trials reviewed were conducted on people without psychological difficulties, limiting the generalizability of the results in people with diagnosed mood and anxiety difficulties. Sixteen studies demonstrated positive effects for symptoms of anxiety, depression, or stress. Micronutrient supplementation in healthy nonclinical adults has limited benefits for mood and anxiety symptoms, although may convey some subtle general improvements. The evidence for adults with physical or mental ill health is more positive although limited by small samples and variability in nutrients studied. Broad-spectrum nutrient products may be more effective than a selected few. While an effect of micronutrients cannot be dismissed, the variability of the studies makes it extremely challenging to identify specific treatment benefits.

Potentially inappropriate medicines for older adults with intellectual disability: Clinical implications from a medication audit

OBJECTIVE

To investigate medications that have the potential to be inappropriately prescribed for people with intellectual disability (ID) and to explore possible issues surrounding the potential harm that can result from the use of groups of medicines for people with ID who are ageing and living longer.

METHODS

An audit of medical case records of 350 patients under the care of an organisation in New Zealand was undertaken to examine existing medication profiles.

RESULTS

Of the 350 patients, 95% were prescribed at least five or more medicines, with 7% of patients have 10 or more medicines. Increasing prescriptions are evident for those 56 years old and above.

CONCLUSIONS

Medicines that may have been appropriate for people with intellectual disability when they were younger may have the potential to cause harm when they age. It is therefore important that monitoring and evaluation of medications for ageing individuals with intellectual disability are regularly undertaken.

Association Between Cerebral Small Vessel Disease With Antidepressant Use and Depression: 3C Dijon Magnetic Resonance Imaging Study

Background and Purpose- Evidence links antidepressant use with cerebral small vessel disease; however, it remains unclear whether people with depression face comparable risk. This study aims to determine the association between antidepressant drug use and depression with markers of cerebral small vessel disease. Methods- One thousand nine hundred five participants (mean age, 72.5 years; 60% women) without stroke or dementia history underwent brain magnetic resonance imaging at baseline, and 1402 individuals underwent a second magnetic resonance imaging at 4 years. Outcomes were lacunes 3 to 15 mm and white matter hyperintensity volume (cm³) at baseline and follow-up. Exposure to antidepressants was grouped as (1) selective serotonin reuptake inhibitors (n=68), (2) tricyclics (n=40), (3) atypicals (n=24), (4) depressed nonusers (n=303), and (5) nondepressed/nonuser group (reference group, n=1470). Statistical analyses adjusted for propensity scores due to the nonrandomized exposure to antidepressant drugs. Results- There was an association between use of atypical antidepressants with lacunes at baseline (adjusted rate ratio, 2.59 [95% CI, 1.14-5.88]; P=0.023) and follow-up (adjusted rate ratio, 3.05 [95% CI, 1.25-7.43]; P=0.014). Lacunes at baseline were also associated with depressed nonusers (adjusted rate ratio, 1.53 [95% CI, 1.06-2.21]; P=0.023). Selective serotonin reuptake inhibitor users and depressed nonusers displayed higher total, periventricular, and deep white matter hyperintensity volumes at baseline. Selective serotonin reuptake inhibitor users had higher deep white matter hyperintensity volumes at follow-up. Conclusions- Users of atypical antidepressants, selective serotonin reuptake inhibitors, and depressed people without any antidepressant exposure all displayed markers of cerebral small vessel disease higher than the nondepressed/nonuser group. The findings suggest that cerebral small vessel disease is associated with depression and exposure to antidepressants.

Safety and Effectiveness of Long-Term Treatment with Lurasidone in Older Adults with Bipolar Depression: Post-Hoc Analysis of a 6-Month, Open-Label Study

OBJECTIVE

To evaluate the safety and effectiveness of 6 months of treatment with lurasidone in older adults with a diagnosis of bipolar I depression.

DESIGN

Post-hoc analysis of a multicenter, 6-month, open-label extension study.

SETTING

Outpatient.

PARTICIPANTS

Patients aged 55 to 75 years with a DSM-IV-TR diagnosis of bipolar I depression who had completed 6 weeks of double-blind, placebo-controlled treatment with either lurasidone monotherapy (1 study) or adjunctive therapy with lithium or valproate (2 studies).

INTERVENTION

Flexible doses of lurasidone, 20 to 120 mg/day, either as monotherapy, or adjunctive with lithium or valproate.

MEASUREMENTS

Effectiveness was assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS; change from open-label-baseline to month-6, observed case analysis).

RESULTS

A total of 141 older adults entered the extension study (monotherapy, N = 55; 39%; adjunctive therapy, N = 86; 61%). At the end of 6 months of open-label treatment with lurasidone, as monotherapy or adjunctive therapy, minimal changes were observed in the older adult sample in mean weight (-1.0 kg and -0.4 kg, respectively); and median total cholesterol (-2.0 mg/dL and +6.0 md/dL, respectively), triglycerides (+2.5 mg/dL and +6.0 mg/dL, respectively), and HbA1c (0.0% and -0.1%, respectively). Patients treated with 6 months of lurasidone showed a mean improvement on the MADRS in both the monotherapy (-6.2) and adjunctive therapy (-6.7) groups.

CONCLUSIONS

Results of these post-hoc analyses found that up to 7.5 months of lurasidone treatment for bipolar depression in older adults was associated with minimal effects on weight and metabolic parameters, with low rates of switching to hypomania or mania, and was well tolerated. The antidepressant effectiveness of lurasidone in this age group was maintained over the 6-month treatment period.

Antidepressant-like effects and basal immobility depend on age and serotonin transporter genotype

Monoamine uptake inhibitors are common treatments for depression; however, the therapeutic efficacy of these drugs varies widely. Two factors that are commonly linked to clinical outcome are age and serotonin transporter (SERT) genotype. Mouse models provide powerful tools to study consequences of age and genotype on antidepressant-like efficacy; however, to date, systematic studies of this nature are lacking. Here, we used the tail suspension test (TST), a preclinical assay for antidepressant efficacy, to gain insight into age and SERT genotype dependency of immobility time in the TST under control conditions (saline injection) and in response to the tricyclic antidepressant, desipramine (DMI). Immobility after saline injection in juvenile, adolescent, adult, mature adult and middle-aged mice (postnatal days 21, 28, 90, 210 and 300, respectively) significantly increased with age; however, the rate of increase was slower for SERT null (-/-) mice than for wild-type (+/+) or heterozygote (+/-) mice. Desipramine reduced immobility across ages and SERT genotypes. Middle-aged, but not adult, SERT(-/-) mice were significantly more sensitive to DMI than age-matched SERT(+/+) or SERT(+/-) mice. Desipramine was less potent in middle-aged SERT(+/+) and SERT(+/-) mice than in adult SERT(+/+) or SERT(+/-) mice. Regardless of age, DMI's maximal effects were greater in SERT(-/-) mice than in SERT(+/+) or SERT(+/-) mice. These results show that immobility time in the TST varies as a function of age and SERT genotype, underscoring the utility of the TST as a potential model to examine age- and SERT genotype-dependent influences on antidepressant response.

Combined treatment with memantine/es-citalopram for older depressed patients with cognitive impairment: a pilot study

OBJECTIVE

The objective of the study is to assess combined antidepressant and memantine treatment in older patients presenting with depression and cognitive impairment.

METHODS

Thirty-five depressed patients with cognitive impairment participated in this open-label pilot study. We evaluated whether, over a 48-week period, combined antidepressant (primarily es-citalopram) and memantine treatment was effective in the treatment of cognitive impairment and depression. Neuropsychological testing was performed, and antidepressant response monitored at baseline and at the 12, 24, and 48-week time points.

RESULTS

Treatment with escitalopram (mean daily dose 18.62 mg, SD 5.15) and memantine (mean daily dose 13.62 mg, SD 6.67) was associated with improvement in Hamilton Depression Rating Scale scores over the 48-week study period. Patients demonstrated significant improvement in the primary outcome of cognitive performance (Selective Reminding Test total immediate recall; SRT-IR) over the 48-week treatment period (p = 0.0147). Significant improvement was also observed in measures of naming and verbal fluency but not in the other cognitive domains. One of the 35 patients (2.9%) converted to Alzheimer's disease over the 48-week treatment period. In the amnestic mild cognitive impairment subsample (n = 22), the conversion rate was 4.5%, a rate lower than in other reports of patients with DEP-CI.

CONCLUSIONS

In this open-label trial, combined antidepressant and memantine treatment in patients with DEP-CI was associated with improved cognition and a low rate of conversion to dementia compared with published studies in patients with DEP-CI. Although limited by the open-label study design that incorporates practice effects that can improve cognitive test performance, the findings suggest the need for a larger randomized placebo-controlled trial.

Predicting risk of adverse drug reactions in older adults

Adverse drug reactions (ADRs) are common in older adults, with falls, orthostatic hypotension, delirium, renal failure, gastrointestinal and intracranial bleeding being amongst the most common clinical manifestations. ADR risk increases with age-related changes in pharmacokinetics and pharmacodynamics, increasing burden of comorbidity, polypharmacy, inappropriate prescribing and suboptimal monitoring of drugs. ADRs are a preventable cause of harm to patients and an unnecessary waste of healthcare resources. Several ADR risk tools exist but none has sufficient predictive value for clinical practice. Good clinical practice for detecting and predicting ADRs in vulnerable patients includes detailed documentation and regular review of prescribed and over-the-counter medications through standardized medication reconciliation. New medications should be prescribed cautiously with clear therapeutic goals and recognition of the impact a drug can have on multiple organ systems. Prescribers should regularly review medication efficacy and be vigilant for ADRs and their contributory risk factors. Deprescribing should occur at an individual level when drugs are no longer efficacious or beneficial or when safer alternatives exist. Inappropriate prescribing and unnecessary polypharmacy should be minimized. Comprehensive geriatric assessment and the use of explicit prescribing criteria can be useful in this regard.

Characterization of brain mGluR5 binding in a pilot study of late-life major depressive disorder using positron emission tomography and [¹¹C]ABP688

The metabotropic glutamate receptor subtype 5 (mGluR5) has been implicated in the pathophysiology of mood and anxiety disorders and is a potential treatment target in major depressive disorder (MDD). This study compared brain mGluR5 binding in elderly patients suffering from MDD with that in elderly healthy volunteers using positron emission tomography (PET) and [(11)C]ABP688. Twenty elderly (mean age: 63.0 ± 6.3) subjects with MDD and twenty-two healthy volunteers in the same age range (mean age: 66.4 ± 7.3) were examined with PET after a single bolus injection of [(11)C]ABP688, with many receiving arterial sampling. PET images were analyzed on a region of interest and a voxel level to compare mGluR5 binding in the brain between the two groups. Differences in [(11)C]ABP688 binding between patients with early- and late-onset depression were also assessed. In contrast to a previously published report in a younger cohort, no significant difference in [(11)C]ABP688 binding was observed between elderly subjects with MDD and healthy volunteers. [(11)C]ABP688 binding was also similar between subgroups with early- or late-onset depression. We believe this is the first study to examine mGluR5 expression in depression in the elderly. Although future work is required, results suggest potential differences in the pathophysiology of elderly depression versus depression earlier in life.

Duloxetine: a review of its use in the management of major depressive disorder in older adults

Duloxetine (Cymbalta(®)) is a selective serotonin norepinephrine reuptake inhibitor indicated for the treatment of major depressive disorder (MDD). This article reviews the therapeutic efficacy and tolerability of duloxetine in older adults with MDD and summarizes its pharmacological properties. Treatment with duloxetine significantly improved several measures of cognition, depression, anxiety, pain and health-related quality-of-life (HR-QOL) in older adults with MDD in two 8-week, double-blind, placebo-controlled trials. However, no significant improvements in measures of depression were observed at week 12 (primary endpoint) of a 24-week, double-blind trial, although symptoms of depression did improve significantly at earlier timepoints. Benefit of treatment was also observed during continued therapy in the 24-week study (i.e. after the 12-week primary endpoint) and in an open-label, 52-week study, with improvements being observed in some measures of depression, pain and HR-QOL. Duloxetine was generally well tolerated in these studies, with nausea, dizziness and adverse events reflecting noradrenergic activity (e.g. dry mouth, constipation) being the most common treatment-emergent adverse events during treatment for up to 52 weeks. Duloxetine therapy had little effect on cardiovascular parameters and bodyweight. Although further well designed and long-term studies in this patient population are required to confirm the efficacy of duloxetine and to compare it with that of other antidepressants, current evidence suggests that treatment with duloxetine may be beneficial in older adults with MDD.

Physical activity in depressed elderly. A systematic review

Background:

exercise may reduce depressive symptoms both in healthy aged populations and in old patients diagnosed with MDD, but few specific analysis were conducted on the efficacy of exercise as an adjunctive treatment with antidepressants, which may be probably more useful in clinical practice, considered the high prevalence of treatment resistant depression in late life, the low cost and safety of physical activity interventions.

Objective:

to establish the new findings on the effectiveness of exercise on depression in elderlies, with particular focus on the efficacy of the exercise as an adjunctive treatment with antidepressants drug therapy.

Method:

the search of significant articles was carried out in PubMed/Medline with the following key words: “exercise”, “physical activity”, “physical fitness”, “depressive disorder”, “depression”, “depressive symptoms”, “late life”, “old people”, and “elderly”.

Results:

44 papers were retrieved by the search. Among the 10 included randomized controlled trials, treatment allocation was adequately conceived in 4 studies, intention-to-treat analysis was performed in 6 studies, but no study had a double-blinded assessment. We examined and discussed the results of all these trials.

Conclusion:

in the last 20 years, few progresses were done in showing the efficacy of exercise on depression, due in part to the persistent lack of high quality research, in part to clinical issues of management of depression in late life, in part to the difficult to establish the real effectiveness of exercise on depressive symptoms in elderlies. However, there are some promising findings on physical activity combined with antidepressants in treatment resistant late life depression.

Duloxetine in affective disorders: a naturalistic study on psychiatric and medical comorbidity, use in association and tolerability across different age groups

Objective:

Duloxetine, a selective serotonin and norepinephrine reuptake inhibitor (SNRI), is currently approved in many countries for the treatment of Major Depressive Disorder (MDD) and Generalized Anxiety Disorder (GAD). The present naturalistic study was aimed to investigate tolerability of Duloxetine in a sample of patients with affective disorders and psychiatric/medical comorbidity, comparing tolerability in monotherapy versus polytherapy and across different age groups.

Methods:

The sample included 165 patients, affected by anxiety and/or mood disorders with or without comorbidity, who had been taken Duloxetine for at least 1 month. Sample variables were collected through a retrospective chart review.

Results:

Most common primary diagnoses were MDD (49.1 %), Bipolar Disorder (BD) (15.7 %) and GAD (5.5%). The 40 % of the sample had psychiatric comorbidity: in particular, anxiety disorders (15.8 %) (GAD 7.9%, Panic Disorder –PD- 7.3%) and personality disorders (9.1%) as the most frequent ones. With respect to medical comorbidities (68% of the sample), hypertension (12.1%) and diabetes (7.3%) were the most common ones. Mean duration of treatment and dosage of Duloxetine were, respectively, 11 months (± 9.1) and 70 mg/day (± 28.6). The 68 % of the sample received Duloxetine in association with other drugs. Minor side-effects, in particular drowsiness and gastrointestinal problems, were reported by 15 % of the sample. No difference in terms of tolerability across distinct groups, divided on the basis of mono- vs polytherapy as well as of different age, was found.

Conclusion:

Duloxetine, mostly administered in patients with affective disorders with psychiatric/ medical comorbidity and in association with other drugs, appeared to be well tolerated, showing limited rates of side effects of mild intensity. Further naturalistic studies are warranted to confirm present results.

A review of duloxetine 60 mg once-daily dosing for the management of diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain due to chronic osteoarthritis pain and low back pain

BACKGROUND

Duloxetine is a selective dual neuronal serotonin (5-Hydroxytryptamine, 5-HT) and norepinephrine reuptake inhibitor (SSNRI). It is indicated in the United States for treatment of major depressive disorder (MDD), generalized anxiety disorder (GAD), and several chronic pain conditions, including management of diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain due to chronic osteoarthritis (OA) pain and chronic low back pain (LBP). Its use for antidepressant and anxiolytic actions has been extensively reviewed previously. We here review the evidence for the efficacy of 60 mg once-daily dosing of duloxetine for chronic pain conditions.

METHOD

The literature was searched for clinical trials in humans conducted in the past 10 years involving duloxetine.

RESULTS

There were 199 results in the initial search. Studies not in the English language were excluded. We then included only studies of diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain (OA and LBP). Studies of painful symptoms reported in mental health studies were excluded. This resulted in 32 studies. Articles that did not include a 60 mg/day daily dose as a study arm were excluded. This resulted in 30 studies, broken down as follows: 12 for diabetic peripheral neuropathy, 9 for fibromyalgia, 6 for LBP, and 3 for OA pain.

CONCLUSIONS

The studies reviewed report that duloxetine 60 mg once-daily dosing is an effective option for the management of diabetic peripheral neuropathic pain, fibromyalgia, and chronic musculoskeletal pain due to chronic OA pain and chronic LBP. As these pains are often comorbid with MDD or GAD, duloxetine might possess the pharmacologic properties to be a versatile agent able to address several symptoms in these patients. With adequate attention to FDA prescribing guidance regarding safety and drug-drug interactions, duloxetine 60 mg once-daily dosing appears to be an effective option in the appropriate pain patient population.

The pathophysiology of chronic constipation

Constipation is broadly defined as an unsatisfactory defecation characterized by infrequent stools, difficult stool passage or both. The common approach to the pathophysiology of constipation groups the disorder into primary and secondary causes. Primary causes are intrinsic problems of colonic or anorectal function, whereas secondary causes are related to organic disease, systemic disease or medications. The normal process of colonic transit and defecation is discussed, and the etiology of constipation is reviewed.

Prevalence and characteristics of antidepressant drug prescriptions in older Italian patients

BACKGROUND

During last few decades, the proportion of elderly persons prescribed with antidepressants for the treatment of depression and anxiety has increased. The aim of this study was to evaluate prevalence of antidepressant prescription and related factors in elderly in-patients, as well as the consistency between prescription of antidepressants and specific diagnoses requiring these medications.

METHODS

Thirty-four internal medicine and four geriatric wards in Italy participated in the Registro Politerapie SIMI-REPOSI study during 2008. In all, 1,155 in-patients, 65 years or older, were enrolled. Prevalence of the use of antidepressants was calculated at both admission and discharge. Logistic regression was used to evaluate the association between patients' characteristics (age, gender, Charlson Index, number of drugs, specific diseases, other psychotropic medications) and the prescription of antidepressants.

RESULTS

The number of patients treated with antidepressant medication at hospital admission was 115 (9.9%) and at discharge 119 (10.3%). In a multivariate analysis, a higher number of drugs (OR = 1.2; 95% CI = 1.1-1.3), use of anxiolytic drugs (OR = 2.1; 95% CI = 1.2-3.6 and OR = 3.8; 95% CI = 2.1-6.8), and a diagnosis of dementia (OR = 6.1; 95% CI = 3.1-11.8 and OR = 5.8; 95% CI = 3.3-10.3, respectively, at admission and discharge) were independently associated with antidepressant prescription. A specific diagnosis requiring the use of antidepressants was present only in 66 (57.4%) patients at admission and 76 (66.1%) at discharge.

CONCLUSIONS

Antidepressants are commonly prescribed in geriatric patients, especially in those receiving multiple drugs, other psychotropic drugs, and those affected by dementia. There is an inconsistency between the prescription of antidepressants and a specific diagnosis that the hospitalization only slightly improves.

Psychotropic drug-related problems in the elderly

Almost any drug therapy has the potential to cause iatrogenic complications for older people, but the risk is particularly significant for those being treated for major psychiatric illnesses. In the past, focus was centered mostly upon relatively obvious forms of drug-related harm, such as adverse drug reactions and drug interactions, but it is clear that this approach substantially under-represents the extent of the problem. Other, more inclusive categorization systems can be used to capture a broader representation of the profile and severity of medication-related problems, and these can provide insight into more subtle concerns. Analysis of psychotropic drug-related problems in the elderly provides a basis for individual interventions to lessen the impact of iatrogenic harm, as well as systematic approaches that can be used in the clinical setting to diminish the likelihood of preventable problems in a vulnerable patient population.

Safe prescribing for the elderly

Prescribing for older adults is a complex and high-risk process. Age-related changes produce differences in the way lderly patients respond to and process medication. This article discusses age-related changes, common problems that increase risk for older adults, strategies for improving adherence, and models for safe and effective prescribing.

A fluorescence displacement assay for antidepressant drug discovery based on ligand-conjugated quantum dots

The serotonin (5-hydroxytryptamine, 5-HT) transporter (SERT) protein plays a central role in terminating 5-HT neurotransmission and is the most important therapeutic target for the treatment of major depression and anxiety disorders. We report an innovative, versatile, and target-selective quantum dot (QD) labeling approach for SERT in single Xenopus oocytes that can be adopted as a drug-screening platform. Our labeling approach employs a custom-made, QD-tagged indoleamine derivative ligand, IDT318, that is structurally similar to 5-HT and accesses the primary binding site with enhanced human SERT selectivity. Incubating QD-labeled oocytes with paroxetine (Paxil), a high-affinity SERT-specific inhibitor, showed a concentration- and time-dependent decrease in QD fluorescence, demonstrating the utility of our approach for the identification of SERT modulators. Furthermore, with the development of ligands aimed at other pharmacologically relevant targets, our approach may potentially form the basis for a multitarget drug discovery platform.