Age as a factor affecting lithium therapy

Improving lithium dose prediction using population pharmacokinetics and pharmacogenomics: a cohort genome-wide association study in Sweden

BACKGROUND

Lithium is the most effective treatment for bipolar disorder, resulting in strong suicide prevention effects. The therapeutic range of lithium, however, is narrow and treatment initiation requires individual titration to address inter-individual variability. We aimed to improve lithium dose prediction using clinical and genomic data.

METHODS

We performed a population pharmacokinetic study followed by a genome-wide association study (GWAS), including two clinical Swedish cohorts. Participants in cohort 1 were from specialised outpatient clinics at Huddinge Hospital, in Stockholm, Sweden, and participants in cohort 2 were identified using the Swedish National Quality Registry for Bipolar disorder (BipoläR). Patients who received a lithium dose corresponding to at least one tablet of lithium sulphate (6 mmol) per day and had clinically relevant plasma concentrations of lithium were included in the study. Data on age, sex, bodyweight, height, creatinine concentration, estimated glomerular filtration rate (eGFR), lithium preparation, number of tablets of lithium per day, serum lithium concentration, and medications affecting kidney function (C09 antihypertensives, C03 [except C03D] sodium-retaining diuretics, and non-steroidal anti-inflammatory drugs) were obtained retrospectively for several timepoints when possible from electronic health records, BipoläR, and the Swedish prescription registry. The median time between timepoints was 1·07 years for cohort 1 and 1·09 years for cohort 2. The primary outcome of interest was the natural logarithm of total body clearance for lithium (CL_Li) associated with the clinical variables. The residual effects after accounting for age and sex, representing the individual-level effects (CL_Li,age/sex), were used as the dependent variable in a GWAS.

FINDINGS

2357 patients who were administered lithium (1423 women [60·4%] and 934 men [39·6%]; mean age 53·6 years [range 17-89], mainly of European descent) were included and 5627 data points were obtained. Age (variance explained [R²]: R²_cohort1=0·41 and R²_cohort2=0·31; both p<0·0001), sex (R²_cohort1=0·0063 [p=0·045] and R²_cohort2=0·026 [p<0·0001]), eGFR (R²_cohort1=0·38 and R²_cohort2=0·20; both p<0·0001), comedication with diuretics (R²_cohort1=0·0058 [p=0·014] and R²_cohort2=0·0026 [p<0·0001]), and agents acting on the renin-aldosterone-angiotensin system (R²_cohort1=0·028 and R²_cohort2=0·015; both p<0·0001) were clinical predictors of CL_Li. Notably, an association between CL_Li and serum lithium was observed, with a lower CL_Li being associated with higher serum lithium (R²_cohort1=0·13 and R²_cohort2=0·15; both p<0·0001). In a GWAS of CL_Li,age/sex, one locus was associated with a change in CL_Li (rs583503; β=-0·053 [95% CI -0·071 to -0·034]; p<0·00000005). We also found enrichment of the associations with genes expressed in the medulla (p=0·0014, corrected FDR=0·04) and cortex of the kidney (p=0·0015, corrected FDR=0·04), as well as associations with polygenic risk scores for eGFR (p value threshold: 0·05, p=0·01), body-mass index (p value threshold: 0·05, p=0·00025), and blood urea nitrogen (p value threshold: 0·001, p=0·00043). The model based on six clinical predictors explained 61·4% of the variance in CL_Li in cohort 1 and 49·8% in cohort 2. Adding genetic markers did not lead to major improvement of the models: within the subsample of genotyped individuals, the variance explained only increased from 59·32% to 59·36% in cohort 1 and from 49·21% to 50·03% in cohort 2 when including rs583503 and the four first principal components.

INTERPRETATION

Our model predictors could be used clinically to better guide lithium dosage, shortening the time to reach therapeutic concentrations, thus improving care. Identification of the first genomic locus and PRS to be associated with CL_Li introduces the opportunity of individualised medicine in lithium treatment.

FUNDING

Stanley Medical Research Institute, Swedish Research Council, Swedish Foundation for Strategic Research, Swedish Brain Foundation, Swedish Research Council, Söderström-Königska Foundation, Bror Gadelius Minnesfond, Swedish Mental Health Fund, Karolinska Institutet and Hospital.

Tolerability of lithium: A naturalistic discontinuation study in older inpatients (≥60 years)

OBJECTIVES

Lithium is one of the most effective treatment options in both bipolar disorder and treatment-resistant depression. The use of lithium in older patients declined during the last decades, probably resulting in undertreatment of older patients. To investigate how well lithium is tolerated in old age, we aimed to determine the frequency, reasons, and possible predictors of discontinuation due to adverse effects in a cohort of inpatients ≥60 years who had started with lithium.

METHODS

We performed a retrospective cohort study based on chart reviews. Participants were in treatment at Parnassia Group at The Hague, The Netherlands. After inclusion (between January 2010 and December 2016), participants were followed until April 2017, when we performed data extraction and analysis.

RESULTS

In our sample of 135 patients (median age 69 years, median follow-up duration 18 months), 49 (36.3%) participants discontinued lithium. Only a minority (11 [8.1%]) of the participants discontinued solely due to adverse effects. The majority discontinued lithium due to psychiatric (18, 5%) reasons (most commonly mentioned within this subgroup: lack of effectiveness and noncompliance) or a combination of reasons (7.4%). None of the factors we studied (age, gender, Charlson Comorbidity Index, polypharmacy, renal function, and neurological history) were significantly associated with discontinuation due to adverse effects.

CONCLUSIONS

The frequency of lithium discontinuation in our cohort was in range with frequencies reported in younger patients. Older age itself should not be a reason to withhold lithium treatment.

The role of brain barriers in the neurokinetics and pharmacodynamics of lithium

Lithium (Li) is the most widely used mood stabilizer in treating patients with bipolar disorder. However, more than half of the patients do not or partially respond to Li therapy, despite serum Li concentrations in the serum therapeutic range. The exact mechanisms underlying the pharmacokinetic-pharmacodynamic (PK-PD) relationships of lithium are still poorly understood and alteration in the brain pharmacokinetics of lithium may be one of the mechanisms explaining the variability in the clinical response to Li. Brain barriers such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB) play a crucial role in controlling blood-to-brain and brain-to-blood exchanges of various molecules including central nervous system (CNS) drugs. Recent in vivo studies by nuclear resonance spectroscopy revealed heterogenous brain distribution of Li in human that were not always correlated with serum concentrations, suggesting regional and variable transport mechanisms of Li through the brain barriers. Moreover, alteration in the functionality and integrity of brain barriers is reported in various CNS diseases, as a cause or a consequence and in this regard, Li by itself is known to modulate BBB properties such as the expression and activity of various transporters, metabolizing enzymes, and the specialized tight junction proteins on BBB. In this review, we will focus on recent knowledge into the role of the brain barriers as key-element in the Li neuropharmacokinetics which might improve the understanding of PK-PD of Li and its interindividual variability in drug response.

The effect of age, sex and strains on the performance and outcome in animal models of stroke

Stroke is one of the leading causes of death worldwide, and the majority of cerebral stroke is caused by occlusion of cerebral circulation, which eventually leads to brain infarction. Although stroke occurs mainly in the aged population, most animal models for experimental stroke in vivo almost universally rely on young-adult rodents for the evaluation of neuropathological, neurological, or behavioral outcomes after stroke due to their greater availability, lower cost, and fewer health problems. However, it is well established that aged animals differ from young animals in terms of physiology, neurochemistry, and behavior. Stroke-induced changes are more pronounced with advancing age. Therefore, the overlooked role of age in animal models of stroke could have an impact on data quality and hinder the translation of rodent models to humans. In addition to aging, other factors also influence functional performance after ischemic stroke. In this article, we summarize the differences between young and aged animals, the impact of age, sex and animal strains on performance and outcome in animal models of stroke and emphasize age as a key factor in preclinical stroke studies.

Cognitive benefits of lithium chloride in APP/PS1 mice are associated with enhanced brain clearance of β-amyloid

Epidemiological evidence suggests that people with bipolar disorder prescribed lithium exhibit a lower risk of Alzheimer's disease (AD) relative to those prescribed other mood-stabilizing medicines. Lithium chloride (LiCl) reduces brain β-amyloid (Aβ) levels, and the brain clearance of Aβ is reduced in AD. Therefore, the purpose of this study was to assess whether the cognitive benefits of LiCl are associated with enhanced brain clearance of exogenously-administered Aβ. The brain clearance of intracerebroventricularly (icv) administered ¹²⁵I-Aβ₄₂ was assessed in male Swiss outbred mice administered daily oral NaCl or LiCl (300 mg/kg for 21 days). LiCl exhibited a 31% increase in the brain clearance of ¹²⁵I-Aβ₄₂ over 10 min, which was associated with a 1.6-fold increase in brain microvascular expression of the blood-brain barrier efflux transporter low density lipoprotein receptor-related protein 1 (LRP1) and increased cerebrospinal fluid (CSF) bulk-flow. 8-month-old female wild type (WT) and APP/PS1 mice were also administered daily NaCl or LiCl for 21 days, which was followed by cognitive assessment by novel object recognition and water maze, and measurement of soluble Aβ₄₂, plaque-associated Aβ₄₂, and brain efflux of ¹²⁵I-Aβ₄₂. LiCl treatment restored the long-term spatial memory deficit observed in APP/PS1 mice as assessed by the water maze (back to similar levels of escape latency as WT mice), but the short-term memory deficit remained unaffected by LiCl treatment. While LiCl did not affect plaque-associated Aβ₄₂, soluble Aβ₄₂ levels were reduced by 49.9% in APP/PS1 mice receiving LiCl. The brain clearance of ¹²⁵I-Aβ₄₂ decreased by 27.8% in APP/PS1 mice, relative to WT mice, however, LiCl treatment restored brain ¹²⁵I-Aβ₄₂ clearance in APP/PS1 mice to a rate similar to that observed in WT mice. These findings suggest that the cognitive benefits and brain Aβ₄₂ lowering effects of LiCl are associated with enhanced brain clearance of Aβ₄₂, possibly via brain microvascular LRP1 upregulation and increased CSF bulk-flow, identifying a novel mechanism of protection by LiCl for the treatment of AD.

Lithium in late-life mania: a systematic review

The prevalence of mania among >65-year-olds ranges from 0.1% to 0.4% and its treatment is a particular challenge for clinicians. Although lithium is the treatment of choice for bipolar disorder (BD), its use in elderly population was recently questioned. This study provides a comprehensive review of literature on the efficacy and tolerability of lithium as a pharmacologic treatment for mania in elderly BD patients. We conducted a systematic review, based on PRISMA guidelines, of articles published between 1970 and August 2016 and indexed in the following databases: EMBASE, MEDLINE, Cochrane Library Databases and PsycINFO. The key words "age", "late-life", "geriatric", "elderly", and "older" were combined with words indicating pharmacologic treatments, such as lithium and other mood stabilizers and with the diagnostic terms "bipolar disorder" and "mania". Fifteen out of 196 retrieved studies met our inclusion criteria. Seven studies evaluated both the efficacy and tolerability of lithium treatment in elderly BD patients; a further three evaluated only the efficacy and five assessed tolerability. Only limited data on the treatment of elderly BD patients are available, but evidence suggests that lithium is effective and tolerated in this subgroup of patients and thus should remain a first-line drug. It seems to be more effective at lower doses and close monitoring of plasma concentrations is necessary.

A survey of patients' knowledge about lithium therapy in the elderly

OBJECTIVE

Lithium is commonly used in the treatment of various psychiatric disorders. It has a narrow therapeutic range and a mortality rate of 9% in patients intoxicated during maintenance therapy. Therefore, for lithium to be prescribed safely, clinicians must ensure that patients are aware of features of lithium toxicity. We aim to identify patients' knowledge of lithium in the elderly population and associated factors that may influence this knowledge.

METHOD

The Lithium Knowledge Test (LKT) is a brief questionnaire that was developed as a means of identifying patients' practical and pharmacologic knowledge, which is important if therapy is to be safe and effective. The survey was conducted in the outpatient service of the Department of Old Age Psychiatry attached to a university teaching hospital in an urban area in Ireland between January 2011 and July 2011. A total of 33 patients participated in the survey, and the LKT questionnaires were completed by all participants. The LKT scores are obtained by adding up the responses to the questions, while the LKT hazard scores are obtained by adding together the responses to the questions on symptoms of toxicity. The result was analyzed using SPSS version 20 (SPSS Inc, Chicago, Illinois), and the relationships between LKT scores and LKT hazard scores as well as other variables were examined using Pearson's correlation coefficient.

RESULTS

The mean LKT score of our sample population was 4.45, suggestive of poor knowledge of lithium, and the mean LKT hazard score was 5.85, highly suggestive of potentially hazardous lack of knowledge. There was a significant negative correlation between the LKT score and hazard score (r = -0.65, P < .01 [1-tailed]).

CONCLUSIONS

The survey results highlight the need for patients to be given comprehensive information about lithium prior to commencement of treatment and a refresher educational program during lithium therapy.

The effects of lithium on renal function in older adults--a systematic review

Chronic renal failure (CRF) and nephrogenic diabetes insipidus (NDI) are potential consequences of chronic lithium use, while acute renal failure (ARF) has been described in lithium intoxication. We performed a systematic review of all studies pertaining to the effects of lithium on the kidney in older adults. The ARF incidence was 1.5% per person-year and concurrent loop diuretic and angiotensin-converting enzyme inhibitor use with lithium increased the risk. The CRF prevalence estimates varied from 1.2% to 34%, with risk factors including age, previous lithium intoxication, polyuria, previously impaired renal function, and decreased maximal urine osmolality. The prevalence of NDI varied widely from 1.8%  to 85%. Risk factors included lithium duration, dose, level, slow-release formulation, and clinical nonresponse. Except for amiloride use in NDI, there is little evidence for treatment of other lithium-induced adverse renal effects. Currently, there is no compelling evidence to suggest that lithium should be avoided in elderly patients for fear of renal side effects.

Elderly and drugs: risks and necessity of rational use

In recent decades, the world has undergone a demographic transformation with a rapid growth of the elderly population, resulting in an increased demand for funds to maintain their health and drug consumption. Pharmacokinetic and pharmacodynamic changes occurring in the elderly can interfere directly in the adverse effects of drugs and increase the risk of intoxication. In addition, there are external factors interfering with the pharmacotherapy of the elderly, such as inappropriate use and the lack of access to information. Many therapeutic classes of drugs should be used with caution or avoided in the elderly population, such as anti-inflammatory and some anti-hypertensive drugs, diuretics and digitalis. If not managed carefully, these medicines can affect the safety and quality of life in the elderly. Thus, the aim of this review was to identify drugs that should be used with caution in elderly patients in order to avoid intoxication and/or adverse drug events.

Conceptual and methodological issues in designing a randomized, controlled treatment trial for geriatric bipolar disorder: GERI-BD

AIM

This report considers the conceptual and methodological concerns confronting clinical investigators seeking to generate knowledge regarding the tolerability and benefits of pharmacotherapy in geriatric bipolar disorder (BD) patients.

METHOD

There is continuing need for evidence-based guidelines derived from randomized controlled trials that will enhance drug treatment of geriatric BD patients. Therefore, we present the complex conceptual and methodological choices encountered in designing a multisite clinical trial and the decisions reached by the investigators with the intention that study findings be pertinent to, and can facilitate, routine treatment decisions.

RESULTS

Guided by a literature review and input from peers, the tolerability and antimanic effects of lithium and valproate were judged to be the key mood stabilizers to investigate with regard to treating bipolar I disorder manic, mixed, and hypomanic states. The patient selection criteria are intended to generate a sample that not only experiences common treatment needs but also represents the variety of older patients seen in university-based clinical settings. The clinical protocol guides titration of lithium and valproate to target serum concentrations, with lower levels allowed when necessitated by limited tolerability. The protocol emphasizes initial monotherapy. However, augmentation with risperidone is permitted after three weeks when indicated by operational criteria.

CONCLUSIONS

A randomized, controlled trial that both investigates commonly prescribed mood stabilizers and maximizes patient participation can meaningfully address high-priority clinical concerns directly relevant to the routine pharmacologic treatment of geriatric BD patients.

Brain lithium levels and effects on cognition and mood in geriatric bipolar disorder: a lithium-7 magnetic resonance spectroscopy study

OBJECTIVES

The authors investigated the relationship between brain lithium, serum lithium and age in adult subjects treated with lithium. In addition, the authors investigated the association between brain lithium and serum lithium with frontal lobe functioning and mood in a subgroup of older subjects.

DESIGN

Cross-sectional assessment.

SETTING

McLean Hospital's Geriatric Psychiatry Research Program and Brain Imaging Center; The Division of Psychiatry, Boston University School of Medicine.

PARTICIPANTS

Twenty-six subjects, 20 to 85 years, with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition-TR bipolar disorder (BD), currently treated with lithium.

MEASUREMENTS

All subjects had measurements of mood (Hamilton Depression Rating Scale [HDRS] and Young Mania Rating Scale) and serum and brain lithium levels. Brain lithium levels were assessed using lithium Magnetic Resonance Spectroscopy. Ten subjects older than 50 years also had assessments of frontal lobe functioning (Stroop, Trails A and B, Wis. Card Sorting Task).

RESULTS

Brain lithium levels correlated with serum lithium levels for the group as a whole. However, this relationship was not present for the group of subjects older than 50. For these older subjects elevations in brain (but not serum) lithium levels were associated with frontal lobe dysfunction and higher HDRS scores. The higher HDRS were associated with increased somatic symptoms.

CONCLUSION

Frontal lobe dysfunction and elevated depression symptoms correlating with higher brain lithium levels supports conservative dosing recommendations in bipolar older adults. The absence of a predictable relationship between serum and brain lithium makes specific individual predictions about the "ideal" lithium serum level in an older adult with BD difficult.

Prescription patterns of psychotropic medications in elderly compared with younger participants who achieved a "recovered" status in the systematic treatment enhancement program for bipolar disorder

OBJECTIVES

This study compares prescription patterns between young adults and elderly with bipolar disorder who achieved a recovery status during the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD).

DESIGN

STEP-BD is a multicenter National Institute of Mental Health-funded project designed to evaluate the longitudinal outcome of patients with bipolar disorder. The STEP-BD study involved extensive assessment across multiple domains including demographic data, diagnosis, symptom severity, treatment, and clinical status. Patients achieved "recovered" status when they experienced eight consecutive weeks without significant symptoms.

PARTICIPANTS

The authors analyzed data of all subjects who achieved a recovered status at least once in their participation.

MEASUREMENTS

The authors compared treatment regimes and doses among young participants with middle age (N = 3,364), 20-59 years old, and older participants 60 and above (N = 246).

RESULTS

Of the 3,615 STEP-BD participants who had a lifetime diagnosis of bipolar subtypes I or II, 67.6% (N = 2442) achieved a recovered status during their participation. A total of 78.5% (N = 193) of older patients recovered compared with 66.8% of the younger cohort. On average, participants who reached a recovered status took 2.05 medications with no difference between age groups. Lithium was prescribed to 37.8% of younger patients compared with only 29.5% of older participants. The mean dosages taken by younger and older patients differed significantly only for lithium, valproate, and risperidone with elderly individuals prescribed lower daily dosages. Significant reduction in lithium dosing was observed among individuals aged 50 and older and among individuals 60 and older for valproate. Although valproate was more often prescribed, 42.1% of recovered bipolar elder achieved recovery with lithium alone compared with only 21.3% of the younger cohort.

CONCLUSION

This data shows recovery is achievable in the elderly though more than one medication is often needed regardless of age.

A new accurate method for predicting lithium clearance and daily dosage requirements in adult psychiatric patients

OBJECTIVE

The present study aimed to derive new equations for estimating lithium clearance and daily dosage requirements needed to achieve an intended lithium serum level for adult psychiatric inpatients and outpatients.

METHODS

Data were retrospectively collected from 60 adult psychiatric patients (34 males and 26 females, aged between 18-80 years) in both inpatient and outpatient settings. All variables that might affect lithium clearance and/or lithium serum concentration were included and analyzed by stepwise multiple linear regression to produce equations describing lithium clearance and daily dosage requirements for these patients. The validation of the developed equations was performed by application to another 60 psychiatric subjects in both the inpatient and outpatient settings. The bias and accuracy of the new methods were also compared to those set forth by the empirical method and the a priori methods developed by Zetin, Pepin, Jermain and Terao and colleagues.

RESULTS

The following prediction equations for lithium clearance (CL(Li)) were obtained: CL(Li) (inpatients) = 0.932 + 0.185CL(Cr) and CL(Li) (outpatients) = 1.021 + 0.141CL(Cr). The equations derived for daily dosage requirements were: daily dose (inpatients, mg) = 350.15 + 289.92 (desired lithium level, mmol/L) + 0.84 (weight, kg) - 1.76 (age, years) + 34.43 [tricyclic antidepressant (TCA), yes = 1, no = 0] + 62.1(CL(Cr), L/h) + 13.1 [blood urea nitrogen (BUN), mmol/L] + 40.9 (sex, male = 1, female = 0) and daily dose (outpatients, mg) = 784.92 + 530.22 (desired lithium level, mmol/L) + 8.61 (weight, kg) - 12.09 (age, years) - 11.14 (TCA, yes = 1, no = 0) - 7.63 (CL(Cr), L/h) - 42.62 (BUN, mmol/L) - 23.43 (sex, male = 1, female = 0). In the present method, the prediction error for clearance was 10.31% and 6.62% for inpatients and outpatients, respectively, and the prediction error for daily dosage requirements was 3.96% and 2.95% for inpatients and outpatients, respectively.

CONCLUSIONS

Compared to previously reported methods, the present method proved to be accurate and can be safely used for the prediction of lithium clearance and daily dosage requirements in psychiatric inpatients and outpatients.

Treatments for late-life bipolar disorder

BACKGROUND

Bipolar affective disorder is not uncommon in the elderly; prevalence rates in the United States range from 0.1% to 0.4%. However, it accounts for 10% to 25% of all geriatric patients with mood disorders and 5% of patients admitted to geropsychiatric inpatient units. These patients often present a tremendous treatment challenge to clinicians. They frequently have differing treatment needs compared with their younger counterparts because of substantial medical comorbidity and age-related variations in response to therapy. Unfortunately, the management of geriatric bipolar disorder has been relatively neglected compared with the younger population. There continues to be a scarcity of published, controlled trials in the elderly, and no treatment algorithms specific to bipolar disorder in the elderly have been devised.

OBJECTIVE

The goal of this article was to review the current literature on both the pharmacologic and nonpharmacologic management of late-life bipolar disorder.

METHODS

English-language articles written on the treatment of bipolar disorder in the elderly were identified. The first step in data collection involved a search for evidence-based clinical practice guidelines in the Cochrane Database of Systematic Reviews (up until the third quarter of 2006). Systematic reviews were then located in the following databases: MEDLINE (1966-September 2006), EMBASE (1980-2006 [week 36]), and PsycINFO (1967-September 2006 [week 1]). Additional use was made of these 3 databases in searching for single randomized controlled trials, meta-analyses, cohort studies, case-control studies, case series, and case reports. "Elderly," used synonymously with "geriatric," was defined as individuals aged > or =60 years. However, to take into account ambiguity in the nomenclature, the key words aged, geriatric, elderly, and older were combined with words indicating pharmacologic treatments such as pharmacotherapy; classes of medications (eg, lithium, antidepressants, antipsychotics, anticonvulsants, benzodiazepines); and names of selected individual medications (eg, lithium, valproic acid, lamotrigine, carbamazepine, oxcarbazepine, topiramate, gabapentin, zonisamide, clozapine, risperidone, olanzapine, quetiapine, ziprasidone, aripiprazole). These terms were then combined with the diagnostic terms bipolar disorder, mania, hypomania, depression, or bipolar depression. Finally, the terms ECT and psychotherapy were also queried in combination with indicators for age and diagnosis. A few articles on "older adults," usually defined as individuals aged 50 to 55 years, were also included. They may allow for possible extrapolation of data to the geriatric population. Additionally, several mixed-age studies were included for similar considerations. Case reports and case series were described for their potential heuristic value.

RESULTS

Unfortunately, there is a considerable dearth of literature involving evidence-based clinical practice guidelines and even randomized controlled trials in elderly individuals with bipolar disorder. Available options for the treatment of bipolar disorder (including those for mania, hypomania, depression, or maintenance) in the elderly include lithium, antiepileptics, antipsychotics, benzodiazepines, antidepressants, electroconvulsive therapy (ECT), and psychotherapy.

CONCLUSIONS

The data for the treatment of late-life bipolar disorder are limited, but the available evidence shows efficacy for some commonly used treatments. Lithium, divalproex sodium, carbamazepine, lamotrigine, atypical antipsychotics, and antidepressants have all been found to be beneficial in the treatment of elderly patients with bipolar disorder. Although there are no specific guidelines for the treatment of these patients, monotherapy followed by combination therapy of the various classes of drugs may help with the resolution of symptoms. ECT and psychotherapy may be useful in the treatment of refractory disease. There is a need for more controlled studies in this age group before definitive treatment strategies can be enumerated.

Canadian Network for Mood and Anxiety Treatments (CANMAT) guidelines for the management of patients with bipolar disorder: consensus and controversies

Since the previous publication of Canadian Network for Mood and Anxiety Treatments (CANMAT) guidelines in 1997, there has been a substantial increase in evidence-based treatment options for bipolar disorder. The present guidelines review the new evidence and use criteria to rate strength of evidence and incorporate effectiveness, safety, and tolerability data to determine global clinical recommendations for treatment of various phases of bipolar disorder. The guidelines suggest that although pharmacotherapy forms the cornerstone of management, utilization of adjunctive psychosocial treatments and incorporation of chronic disease management model involving a healthcare team are required in providing optimal management for patients with bipolar disorder. Lithium, valproate and several atypical antipsychotics are first-line treatments for acute mania. Bipolar depression and mixed states are frequently associated with suicidal acts; therefore assessment for suicide should always be an integral part of managing any bipolar patient. Lithium, lamotrigine or various combinations of antidepressant and mood-stabilizing agents are first-line treatments for bipolar depression. First-line options in the maintenance treatment of bipolar disorder are lithium, lamotrigine, valproate and olanzapine. Historical and symptom profiles help with treatment selection. With the growing recognition of bipolar II disorders, it is anticipated that a larger body of evidence will become available to guide treatment of this common and disabling condition. These guidelines also discuss issues related to bipolar disorder in women and those with comorbidity and include a section on safety and monitoring.

Age-related changes in pharmacokinetics and pharmacodynamics: basic principles and practical applications

Advancing age is characterized by impairment in the function of the many regulatory processes that provide functional integration between cells and organs. Therefore, there may be a failure to maintain homeostasis under conditions of physiological stress. The reduced homeostatic ability affects different regulatory systems in different subjects, thus explaining at least partly the increased interindividual variability occurring as people get older. Important pharmacokinetic and pharmacodynamic changes occur with advancing age. Pharmacokinetic changes include a reduction in renal and hepatic clearance and an increase in volume of distribution of lipid soluble drugs (hence prolongation of elimination half-life) whereas pharmacodynamic changes involve altered (usually increased) sensitivity to several classes of drugs such as anticoagulants, cardiovascular and psychotropic drugs. This review focuses on the main age-related physiological changes affecting different organ systems and their implications for pharmacokinetics and pharmacodynamics of drugs.

Clinically significant drug interactions with antidepressants in the elderly

Pharmacological treatment of depression in old age is associated with an increased risk of adverse pharmacokinetic and pharmacodynamic drug interactions. Elderly patients may have multiple disease states and, therefore, may require a variety of other drugs. In addition to polypharmacy, other factors such as age-related physiological changes, diseases, genetic constitution and diet may alter drug response and, therefore, predispose elderly patients to adverse effects and drug interactions. Antidepressant drugs currently available differ in their potential for drug interactions. In general, older compounds, such as tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs), have a higher potential for interactions than newer compounds, such as selective serotonin reuptake inhibitors (SSRIs) and other relatively novel agents with a more specific mechanism of action. In particular, TCAs and MAOIs are associated with clinically significant pharmacodynamic interactions with many medications frequently prescribed to elderly patients. Moreover, TCAs may be susceptible to pharmacokinetic interactions when given in combination with inhibitors or inducers of the cytochrome P450 (CYP) isoenzymes involved in their metabolism. Because of a more selective mechanism of action, newer antidepressants have a low potential for pharmacodynamic drug interactions. However, the possibility of the serotonin syndrome should be taken into account when drugs affecting serotonergic transmission, such as SSRIs, venlafaxine or nefazodone, are coadministered with other serotonergic agents. Newer agents have a differential potential for pharmacokinetic interactions because of their selective effects on CYP isoenzymes. Within the group of SSRIs, fluoxetine and paroxetine are potent inhibitors of CYP2D6, while fluvoxamine predominantly affects CYP1A2 and CYP2C19 activity. Therefore, these agents should be closely monitored or avoided in elderly patients treated with substrates of these isoforms, especially those with a narrow therapeutic index. On the other hand, citalopram and sertraline have a low inhibitory activity on different drug metabolising enzymes and appear particularly suitable in an elderly population. Among other newer antidepressants, nefazodone is a potent inhibitor of CYP3A4 and its combination with substrates of this isoform should be avoided.

Conventional and new antidepressant drugs in the elderly

Depression in the elderly is nowadays a predominant health care problem, mainly due to the progressive aging of the population. It results from psychosocial stress, polypathology, as well as some biochemical changes which occur in the aged brain and can lead to cognitive impairments, increased symptoms from medical illness, higher utilization of health care services and increased rates of suicide and nonsuicide mortality. Therefore, it is very important to make an early diagnosis and a suitable pharmacological treatment, not only for resolving the acute episode, but also for preventing relapse and enhancing the quality of life. Age-related changes in pharmacokinetics and in pharmacodynamics have to be kept into account before prescribing an antidepressant therapy in an old patient. In this paper some of the most important and tolerated drugs in the elderly are reviewed. Tricyclic antidepressants have to be used carefully for their important side effects. Nortriptyline, amytriptiline, clomipramine and desipramine as well, seem to be the best tolerated tricyclics in old people. Second generation antidepressants are preferred for the elderly and those patients with heart disease as they have milder side effects and are less toxic in overdose and include the so called atypicals, such as selective serotonin reuptake inhibitors, serotonin noradrenalene reuptake inhibitors and noradrenaline reuptake inhibitors. Monoamine oxidase (MAO) inhibitors are useful drugs in resistant forms of depression in which the above mentioned drugs have no efficacy; the last generation drugs (reversible MAO inhibitors), such as meclobemide, seem to be very successful. Mood stabilizing drugs are widely used for preventing recurrences of depression and for preventing and treating bipolar illness. They include lithium, which is sometimes used especially to prevent recurrence of depression, even if its use is limited in old patients for its side effects, the anticonvulsants carbamazepine and valproic acid. Putative last generation mood stabilizing drugs include the dihydropyridine L-type calcium channel blockers and the anticonvulsants phenytoin, lamotrigine, gabapentin and topiramate, which have unique mechanisms of action and also merit further systematic study. Psychotherapy is often used as an adjunct to pharmacotherapy, while electroconvulsant therapy is used only in the elderly patients with severe depression, high risk of suicide or drug resistant forms.

Differential pharmacokinetics of lithium in elderly patients

The pharmacotherapeutic use of lithium in the elderly as acute and maintenance therapy in bipolar disorder and augmentation therapy for major depression is well documented. Differences in the response to lithium are explained, in part, by the effect of age-related physiological changes, comorbid conditions, and concurrent medications on the pharmacokinetics of lithium in the elderly. The pharmacokinetic profile of lithium has been studied for many years, primarily in younger adult populations. Lithium pharmacokinetics may be influenced by a number of factors including age. It was first noted several years ago that elderly individuals required lower doses of lithium to achieve serum concentrations similar to those observed in younger adults. This is due to the combination of a reduced volume of distribution and reduced renal clearance. The composition of the human body changes with aging producing an increase in body fat, a decrease in fat-free mass and a decrease in total body water. Lithium clearance decreases as the glomerular filtration rate decreases with increasing age. The effects of other medical conditions in the elderly on the pharmacokinetics of lithium are less well delineated. Reduced lithium clearance is expected in patients with hypertension, congestive heart failure or renal dysfunction. Larger lithium maintenance doses are required in obese compared with non-obese patients. The most clinically significant pharmacokinetic drug interactions associated with lithium involve drugs which are commonly used in the elderly. Thiazide diuretics, ACE inhibitors, and nonsteroidal anti-inflammatory drugs can increase serum lithium concentrations. The tolerability of lithium is lower in the elderly. Neurotoxicity clearly occurs in the elderly at concentrations considered 'therapeutic' in general adult populations. There are no placebo-controlled randomised trials of lithium in old age and recommendations for clinical use are based on extrapolations from pharmacokinetic studies, anecdotal reports from mixed age populations and clinical experience in old age psychiatry. Serum concentrations of lithium need to be markedly reduced in the elderly population and particularly so in the very old and frail elderly.

Antidepressant drugs in the elderly

1. In this article some of the most important and tolerated drugs in the elderly are reviewed. 2. Tricyclic antidepressants have to be used carefully because of their important side effects. Nortriptyline and desipramine appear to be the best tolerated tricyclics in old people. 3. Second generation antidepressants are preferred for the elderly and those patients with heart disease as they have milder side effects and are less toxic in overdose. 4. MAO inhibitors are useful drugs in resistant forms of depression in which the above mentioned drugs have no efficacy and the last generation drugs (reversible MAO inhibitors), such as moclobemide, seem to be very successful. 5. Lithium is sometimes used especially to prevent recurrence of depression, even if its use is limited in old patients due to its side effects. 6. Psychotherapy is often used as an adjunct to pharmacotherapy, while electroconvulsant therapy is used only in the elderly patients with severe depression, high risk of suicide, or drug-resistant forms.

Assessment and treatment of bipolar disorder in the elderly

The aetiology of late-onset bipolar disorder is heterogeneous because the disease is more likely to have a secondary (i.e. a medical disorder or medication-induced) cause in older than in younger patients. Elderly patients with bipolar disorder typically require lithium dosages that are 25 to 50% lower than those used in younger individuals. Information on the use of valproic acid (sodium valproate) in elderly patients with bipolar disorder is limited but encouraging. In contrast, there is virtually no information regarding the use of carbamazepine or other drugs in this patient group. Electroconvulsive therapy is well tolerated by older people and can be useful for these patients.

Phenobarbital induces the 2-hydroxylation of desipramine

The kinetics of a single oral dose of desipramine (DMI; 100 mg) were studied in eight epileptic patients chronically treated with phenobarbital (PB) and in eight drug-free healthy controls. All subjects were extensive metabolizers with respect to the genetically determined CYP2D6-related metabolic polymorphism. Compared with controls, epileptic patients exhibited lower peak plasma DMI concentrations (74 +/- 24 vs. 107 +/- 32 nmol/L; means +/- SD, p < 0.05), smaller DMI area-under-the-curve values (1,943 +/- 461 vs. 3,234 +/- 1,145 nmol L-1 h; p < 0.01), and shorter DMI elimination half-lives (15.1 +/- 2.1 vs. 20.6 +/- 3.4 h; p < 0.01). The proportion of the dose excreted as 2-hydroxydesipramine (2-OH-DMI) was significantly higher in the patients (54 +/- 8 vs. 40 +/- 9%; p < 0.05). In one single poor metabolizer volunteer, a 3-week treatment with PB was associated with no major changes in DMI kinetics, but the urinary excretion of 2-OH-DMI tended to increase. These results suggest that PB is an inducer of the 2-hydroxylation of DMI, a reaction primarily catalyzed by CYP2D6, but do not provide further information on the specific P450 isoenzyme(s) being induced.

A Retrospective Chart Review of Lithium Side Effects in a Geriatric Outpatient Population

The charts of 114 elderly outpatients with mood disorders treated with lithium were reviewed to determine the incidence of side effects. Patients had been treated with lithium for an average of 7.5 years, with an average serum lithium level of 0.5. Overall, 61.4% of patients experienced side effects from lithium at some point in their treatment, but only 0.11 side effects occurred per patient per year. Two (1.8%) patients had to discontinue lithium because of side effects and four (3-5%) required hospitalization. Delirium was the most common side effect noted (19.3%). Side effects occurred both at low ("subtherapeutic") and higher serum lithium levels. Variables significantly associated with experiencing side effects included male sex and higher serum lithium level. Hypothyroidism was significantly associated with longer length of time in years treated with lithium.

Clinical pharmacokinetics of antidepressants in the elderly. Therapeutic implications

The prevalence of depression in the elderly suggests that a substantial number of older patients will be treated with an antidepressant medication such as one of the tricyclics, trazodone, fluoxetine or lithium. The physiological changes that accompany aging raise the possibilities of altered pharmacokinetics, patterns of efficacy and adverse effect profiles. The literature addressing the subject of antidepressant use in the elderly has not provided a clear, consistent picture of how these drugs behave in this population in comparison with younger patients. Particularly in the case of the tricyclic antidepressants (TCAs), a large degree of interindividual variation in drug clearance (CL) confounds attempts to find differences attributable to age per se. Study design, however, is also a problem in that very few investigators include a young control group, choosing instead to compare their data with previously reported outcomes. Designations of statistical significance and positive correlation also differ among investigators, and the clinical significance of any finding is not always addressed. The available data suggest that imipramine CL is reduced in the elderly and that amitriptyline CL may be reduced. Desipramine CL does not appear to be affected by age, although decreased renal function in the elderly may lead to accumulation of the hydroxylated metabolite, the clinical importance of which is not known. Nortriptyline is the most thoroughly studied TCA in the elderly. CL seems decisively lower only in elderly patients with concurrent medical illness. The hydroxylated metabolite probably accumulates with diminishing renal function. Not enough data are available on doxepin to make a conclusion. Trazodone CL is diminished somewhat in elderly men. Lithium CL appears to diminish with the declining renal function associated with aging. Fluoxetine data are sparse. Available data do not show any decrease in CL of the parent drug; more information is needed on the metabolite norfluoxetine. Although knowledge of CL changes with aging can help the clinician more accurately achieve the desired steady-state concentration of a drug during long term therapy, much work is still needed to evaluate the relationships among drug concentrations at steady-state, efficacy and adverse effects in the elderly.

Adverse effects of antidepressants in the elderly

Depression is a common problem in old age and the use of antidepressant drugs is particularly prevalent among elderly patients. Limited data suggest that dose requirements may be lower in the elderly because of age-related changes in pharmacokinetics and perhaps also in sensitivity. The side effect profiles of the various antidepressants are reviewed with regard to their potential to cause specific problems in the older patients. Anticholinergic actions, orthostatic hypotension and sedative effects warrant particular care in the elderly.

Lithium augmentation for treatment-resistant depression in the elderly

Lithium has been used successfully to enhance the effectiveness of tricyclic and other antidepressants, monoamine oxidase inhibitors, and combinations of antipsychotics and antidepressants. The safety and efficacy of adding lithium to the treatment regimen was examined in 14 elderly patients with refractory depression. Seven of the 14 had a complete recovery, and three showed a partial response. Side effects, including peripheral weakness, severe fine tremor, and neurotoxicity, necessitated the discontinuation of lithium in three patients. In two other patients with side effects, lower dosages of lithium relieved their symptoms. Lithium augmentation appears to be a promising treatment for geriatric depressed patients who are unresponsive to or cannot tolerate other standard therapies.

The clinical use of lithium carbonate in old age: a review

The authors review the available data concerning the pharmacokinetics and clinical use of lithium carbonate in old age. Guidelines for lithium prophylaxis are provided including a recommendation to maintain 12 hour blood levels at approximately 0.5 mmol/l using a single bedtime dosing regimen. The value of a specialized clinic to manage and monitor elderly patients maintained on lithium is discussed. Empirical clinical findings on the use of lithium may help to elucidate issues of classification in the affective disorders of old age. Increasing clinical data supports a spectrum theory of affective disorder.

Pharmacokinetic changes in aging

A multitude of factors influence the prescribing, dosing, and clinical monitoring of long-term drug therapy in elderly patients. These include life-style and environment, possible multiple disease states and concomitant medications, compliance, and continuous changes in physiology, all of which can--with advancing age--gradually alter the pharmacodynamics and pharmacokinetics of drugs. The physiologic changes associated with aging that can affect the absorption, distribution, excretion, and metabolism of drugs are reviewed and related to the clinical use of several drugs that are widely used in elderly patients. Important clinical factors may also magnify or counteract the physiologic changes that occur with respect to altered drug response. Finally, the pharmacokinetic properties of the available oral hypoglycemic agents are described as they relate to selection of an optimal drug in elderly diabetic patients.

Pharmacologic treatment of agitation associated with dementia

Pharmacotherapy of aggressive or agitated behaviors in the dementia patient has not been studied extensively, despite the prevalence of this problem. Neuroleptics have the most support for efficacy, with shorter acting benzodiazepines demonstrating benefit on occasion. However, studies done to date indicate that these drugs are effective only for a minority of patients and that side effects frequently make patients worse. Other medications, such as propranolol, carbamazepine, or lithium, may be helpful, but their efficacy in dementia patients has not been demonstrated in placebo-controlled studies. Until such studies are done, their use is most appropriate in special patient groups or in patients who have failed neuroleptic or benzodiazepine treatment. More studies are needed in elderly patients evaluating effectiveness of pharmacologic agents in specific types of dementia, particularly Alzheimer's disease. Most studies done to date have been of relatively short duration, usually two months or less. Because these medications often are given to dementia patients for prolonged periods, studies are needed to define the long-term clinical efficacy of these agents. In the clinical setting, these agents should be reduced periodically or discontinued to determine ongoing need. In addition, environmental, social, or behavioral methods of reducing agitated behaviors need to be explored as an adjunct to any medication trial.

Drug monitoring in the elderly

Although the gut changes markedly with age no important differences in drug absorption have yet been demonstrated for any of a wide variety of drugs. Alterations in body structure and function can have important consequences on drug distribution in the elderly. There is a considerable reduction in total body mass with age and the proportion of lean body tissue decreases while there is a relative increase in the amount of adipose tissue. Protein binding of drugs can also be affected by age. Acidic drugs may be bound less in many older patients, mainly because of a general decrease in plasma albumin concentrations. Alpha-1-acid glycoprotein is of importance in the binding of basic drugs and its elevation in the elderly suggests that it may have an important effect on free drug concentration. Drug metabolism generally involves oxidative and conjugative reactions by the hepatic microsomal enzymes. There is little change in conjugative capacity with age although some oxidative pathways have been shown to be impaired. The steady decline in glomerular and tubular function with age is reflected in corresponding decreases in drug elimination for those drugs removed by this route.

Lithium dosage in the elderly. A study with matched age groups

Lithium dosage was examined in 3 age groups (less than or equal to 45 years, 46-64 years, greater than or equal to 65 years) of 78 inpatients, matched on relevant variables. Although mean steady-state lithium plasma levels showed no essential differences, mean daily lithium doses were significantly lower in the elderly. The ratio of weight-related lithium dose to plasma level showed a 36% decline with age (0.58, 0.46 and 0.37 1/kg, P less than 0.0001, analysis of variance). Comparing different decades this ratio, indicating the dose required for a certain plasma level, displayed a clear-cut decrease at 50 years. This may be caused by age-related changes in apparent volume of distribution and/or in elimination half-life of lithium, the latter being the consequence of age-related decrease of glomerular filtration rate.

Psychogeriatrics

Many elderly manifest "functional" psychiatric symptoms that are not necessarily associated with a dementing process. The vast majority of these psychiatric syndromes are amenable to treatment if it is instituted early. Early treatment may prevent institutionalization. Of all age groups, the elderly have the highest suicide rate. The possibility of suicide must be evaluated and openly discussed. Drug abuse and alcoholism should also be considered. The elderly respond to much smaller doses of psychopharmacologic agents and are very sensitive to the side effects of these drugs. Polypharmacy, decreased compliance, and drug-drug interactions are common occurrences in the elderly. Not all psychiatric reactions of the elderly require pharmacologic intervention. Many respond to psychotherapy, which should be used more frequently than has been the practice in the past.

The influence of age on lithium efficacy and side-effects in out-patients

One hundred and sixty-six unipolar and bipolar out-patients (21-78 years) on long-term lithium treatment were studied on a prospective basis. Although there was a possible tendency for manic attacks to increase in prevalence and severity with age, it was difficult to demonstrate a general age-related decline in lithium efficacy. There was a tendency for the prevalence and severity of fine hand tremor to increase with age. This was not seen with polydipsia/polyuria, the other typical lithium side-effect.

Aging and drug disposition--pharmacodynamics

The pharmacodynamics of a drug is defined as the effect of the drug on physiological functions and pathological processes and can be modified in the elderly by (a) pharmacokinetics, (b) receptor sensitivity (or density), (c) impaired homeostasis or (d) pathology. The alterations in pharmacokinetics in the elderly often result in a reduction of the dose required to achieve the optimum pharmacodynamic effect. Changes in the sensitivity of receptors may be decreased in the elderly (perhaps by a diminution in the number of receptors) as in the case of the beta-adrenergic blockers, but increase in sensitivity may also be found as in the case of warfarin. Impairment of homeostatic mechanisms, while related to aging, are frequently produced by pathological processes and have an important influence on the pharmacodynamics of many drugs. The effect of the multiple pathology often found in the elderly is likely to be the dominant factor in changes in pharmacodynamics in this population. The interaction of the above factors results in a heterogeneity of pharmacodynamic response in the elderly which requires the careful monitoring of both the efficacy and toxicity of their drug treatment.

Observations on lithium disposition in the elderly

The disposition kinetics of lithium were studied in six elderly women who had been maintained on this medication for several years. Lithium administration was stopped abruptly. Plasma, whole blood, and erythrocyte half-lives were then measured, as well as renal plasma clearance and distribution volume. Half-life values in whole blood and in its components were found to be similar. The plasma lithium half-life approximated that in younger schizophrenics, but appeared prolonged when compared with half-lives reported for young normal volunteers. Renal plasma clearance and distribution volume of lithium appeared substantially reduced when compared with published values. The data are consistent with altered lithium disposition in the aged.

Effect of age and route of administration on LD50 of lithium chloride in the rat

Male inbred rats were used to determine the lethal dose of lithium chloride. The rats were 3 weeks, 6 weeks, 3 months and 6 months old, and lithium chloride was given intraperitoneally, subcutaneously and orally. In relation to age, LD50 was significantly higher in rats of 6 weeks after oral administration than LD50 in rats of 3 and 6 months. No differences were found following intraperitoneal and subcutaneous administration. In relation to route of administration, LD50 was significantly higher in rats of 3 and 6 weeks after oral administration than LD50 after intraperitoneal and subcutaneous administration. This difference was not found in rats of 3 and 6 months. It is concluded that age and route of administration are of significance for LD50 of lithium chloride in the rat.

Lithium side effects in a routine lithium clinic

Approximately two thirds of a group of bipolar patients attending the routine lithium clinic suffered sid effects. These patients tended to have a lower plasma and erythrocyte lithium concentration and a lower erythrocyte/plasma lithium ratio than those who had no side effects. Explanations of this unexpected finding are discussed.