Possible toxicity of combined fluoxetine and lithium

Lithium toxicity, hypomania and leucocytosis with fluoxetine

The first case in which lithium toxicity and leucocytosis with hypomania appear to have been induced by the selective serotonin reuptake blocking antidepressant, fluoxetine, is described. The possible pathophysiology of this interaction is discussed.

Reversible lithium neurotoxicity: review of the literatur

OBJECTIVE

Lithium neurotoxicity may be reversible or irreversible. Reversible lithium neurotoxicity has been defined as cases of lithium neurotoxicity in which patients recovered without any permanent neurologic sequelae, even after 2 months of an episode of lithium toxicity. Cases of reversible lithium neurotoxicity differ in clinical presentation from those of irreversible lithium neurotoxicity and have important implications in clinical practice. This review aims to study the clinical presentation of cases of reversible lithium neurotoxicity.

DATA SOURCES

A comprehensive electronic search was conducted in the following databases: MEDLINE (PubMed), 1950 to November 2010; PsycINFO, 1967 to November 2010; and SCOPUS (EMBASE), 1950 to November 2010. MEDLINE and PsycINFO were searched by using the OvidSP interface.

STUDY SELECTION

A combination of the following search terms was used: lithium AND adverse effects AND central nervous system OR neurologic manifestation. Publications cited include articles concerned with reversible lithium neurotoxicity.

DATA EXTRACTION

The age, sex, clinical features, diagnostic categories, lithium doses, serum lithium levels, precipitating factors, and preventive measures of 52 cases of reversible lithium neurotoxicity were extracted.

DATA SYNTHESIS

Among the 52 cases of reversible lithium neurotoxicity, patients ranged in age from 10 to 80 years and a greater number were female (P = .008). Most patients had affective disorders, schizoaffective disorders, and/or depression (P < .001) and presented mainly with acute organic brain syndrome. In most cases, the therapeutic serum lithium levels were less than or equal to 1.5 mEq/L (P < .001), and dosage regimens were less than 2,000 mg/day. Specific drug combinations with lithium, underlying brain pathology, abnormal tissue levels, specific diagnostic categories, and elderly populations were some of the precipitating factors reported for reversible lithium neurotoxicity. The preventive measures were also described.

CONCLUSIONS

Reversible lithium neurotoxicity presents with a certain clinical profile and precipitating factors for which there are appropriate preventive measures. This recognition will help in early diagnosis and prompt treatment of lithium neurotoxicity.

Review: Pharmacogenetic aspects of the effect of cytochrome P450 polymorphisms on serotonergic drug metabolism, response, interactions, and adverse effects

The field of pharmacogenetics contains a wealth of potential for the enhancement of clinical practice by providing a more effective match between patient and drug, consequently reducing the probability of an adverse drug reaction. Although a relatively novel concept in the forensic context, pharmacogenetics has the capability to assist in the interpretation of drug related deaths, particularly in unintentional drug poisonings where the cause of death remains unclear. However, the complex pharmacology of the drugs when subjected to genetic variations in metabolism makes interpretation of the expected response and adverse events difficult. Many possess multiple metabolic pathways, narrow therapeutic indices and active metabolites or enantiomers which may be eliminated via different pathways to the parent drug. A number of these drugs, which are metabolised primarily by the CYP450 system, are also associated with serotonin syndrome, or serotonin toxicity, especially when used concomitantly with other serotonin active drugs which rely on the same metabolic pathways for drug elimination. A comprehensive understanding of polymorphic drug metabolism and its expected outcomes is therefore essential when interpreting the involvement of drugs in adverse reactions. This review examines the genetically variable CYP450-mediated metabolism of a number of serotonin-active drugs that are often implicated in cases of serotonin toxicity, to assess the impact of pharmacogenetics on drug metabolism, response, interactions and adverse effects.

Lithium Intoxication Associated With Intramuscular Ziprasidone in Schizoaffective Patients

Antipsychotic agents have been used for the treatment of mood disorders in schizophrenic and schizoaffective patients. It has also been suggested that combinations of lithium and antipsychotics may be more effective than either class alone in treatment of schizoaffective patients. Lithium is known to interact with a variety of medications, including conventional and atypical antipsychotics. Although these combinations are generally well tolerated, they may sometimes lead to various adverse side effects. The authors report two schizoaffective patients with manic psychotic state and psychomotor agitation treated with lithium. Both patients developed symptoms of lithium intoxication after intramuscular ziprasidone treatment. To the best of their knowledge, this is the first description of such an adverse effect of this new atypical neuroleptic drug. They assume that lithium intoxication in the two presented cases was associated with the fast increase of ziprasidone serum level after its parenteral application, possibly affecting lithium excretion and thereby leading to lithium intoxication.

Unipolar late-onset depression: A comprehensive review

Background

The older population increases all over the world and so also does the number of older psychiatric patients, which manifest certain specific and unique characteristics. The aim of this article is to provide a comprehensive review of the international literature on unipolar depression with onset at old age.

Methods

The authors reviewed several pages and books relevent to the subject but did not search the entire literature because of it's overwhelming size. They chose to review those considered most significant.

Results

The prevalence of major depression is estimated to be 2% in the general population over 65 years of age. The clinical picture of geriatric depression differs in many aspects from depression in younger patients. It is not yet clear whether it also varies across cultures and different socio-economic backgrounds. Biological data suggest that it is associated with an increased severity of subcortical vascular disease and greater impairment of cognitive performance. Many authors consider the existence of a somatic disorder to be related to the presence of depression in late life, even constituting a negative prognostic factor for the outcome of depression. Most studies support the opinion that geriatric depression carries a poorer prognosis than depression in younger patients. The therapeutic intervention includes pharmacotherapy, mainly with antidepressants, which is of established value and psychotherapy which is not equally validated.

Conclusion

A significant number of questions regarding the assessment and treatment of geriatric depression remain unanswered, empirical data are limited, and further research is necessary.

Antidepressants, old and new. A review of their adverse effects and toxicity in overdose

The newer antidepressants are as efficacious as the older agents in the treatment of depression. They have a side effect profile that is different from the older drugs and are generally better tolerated. Drug-drug interactions do exist with some of these agents and can usually be predicted from knowledge of their metabolism. When taken in overdose as the sole agents they are rarely fatal; seizures, nausea, vomiting, decreased level of consciousness, and tachycardia are common. In combination with other drugs, toxicity can be more severe. The serotonin syndrome can occur with many of these drugs, and the emergency physician must be vigilant in the evaluation of the overdose patient. CAs and older MAOIs are still in use and remain dangerous when taken in overdose. Patients asymptomatic after a period of observation in the ED usually can be discharged after psychiatric evaluation, when it is required.

Risk of adverse events with the use of augmentation therapy for the treatment of resistant depression

Augmentation therapy is used for those situations where a patient's depression is either treatment-resistant, or partially and/or insufficiently responsive to treatment. It also may be used to attempt to induce a more rapid treatment response. Using drugs together may increase the risk of adverse effects, through potentiation of existing adverse effects or alterations in plasma concentrations of the drug. It is important that clinicians are aware of potential risks of augmentation therapy. Lithium augmentation of a tricyclic antidepressant is relatively well tolerated and the dangers are no greater than using these medications on their own. There are also no reports of serious adverse events when lithium is added to a monoamine oxidase inhibitor. With lithium augmentation of selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitor (SSRI) therapy there have been case reports of the development of a central serotonin syndrome, and thus caution must exercised. A serious concern when using a tricyclic antidepressant to augment an SSRI is the effect of the SSRI on the cytochrome P450 system and the resulting significant increase in tricyclic antidepressant blood concentrations. Augmentation with thyroid hormones appears to be well tolerated and effective. Case reports and open studies indicate that augmentation with buspirone and the psychostimulants, carbamazepine and valproic acid (valproate sodium) is effective and results in minimal adverse effects. However, there is no empirical evidence supporting these results. Recent work supports the tolerability and efficacy of pindolol augmentation. Considerable caution should be exercised when combining psychotropic drugs. The practitioner should only do so with a full knowledge of the compounds involved and their pharmacological properties.

Drug-drug interactions in pediatric psychopharmacology

Serious consequences caused by drug-drug interactions continue to plague contemporary pharmacotherapy. The possibility of a drug-drug interaction should be suspected anytime a new or unexpected effect occurs that complicates the clinical management of a patient in the setting where the patient is receiving more than one drug. In this article, the authors address the mechanisms of pharmacokinetic-based drug-drug interactions focusing on important interactions that may occur with the common medications a pediatrician may prescribe to the child receiving psychoactive medication(s) prescribed by a child psychiatrist.

SSRI-induced extrapyramidal side-effects and akathisia: implications for treatment

The selective serotonin reuptake inhibitors (SSRIs) may occasionally induce extrapyramidal side-effects (EPS) and/or akathisia. This may be a consequence of serotonergically-mediated inhibition of the dopaminergic system. Manifestations of these effects in patients may depend on predisposing factors such as the presence of psychomotor disturbance, a previous history of drug-induced akathisia and/or EPS, concurrent antidopaminergic and/or serotonergic therapy, recent monoamine oxidase inhibitor discontinuation, comorbid Parkinson's disease and possibly deficient cytochrome P450 (CYP) isoenzyme status. There is increasing awareness that there may be a distinct form of melancholic or endogenous depression with neurobiological underpinnings similar to those of disorders of the basal ganglia such as Parkinson's disease. Thus, it is not surprising that some individuals with depressive disorders appear to be susceptible to developing drug-induced EPS and/or akathisia. In addition, the propensity for the SSRIs to induce these effects in individual patients may vary within the drug class depending, for example, on their selectivity for serotonin relative to other monoamines, affinity for the 5-HT2C receptor, pharmacokinetic drug interaction potential with concomitantly administered neuroleptics and potential for accumulation due to a long half-life. The relative risk of EPS and akathisia associated with SSRIs have yet to be clearly established. The potential risks may be reduced by avoiding rapid and unnecessary dose titration. Furthermore, early recognition and appropriate management of EPS and/or akathisia is required to prevent the impact of these effects on patient compliance and subjective well-being. It is important that the rare occurrence of EPS in patients receiving SSRIs does not preclude their use in Parkinson's disease where their potentially significant role requires more systematic evaluation.

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.

[Serotonin syndrome: critical review of the literature]

Since Sternbach's first review, serotonin syndrome has been reported many times. Our purpose was to examine this concept's pertinence, utility and meaning. Its physiopathology remains unclear: 5-HT1A receptors activation is certain, but others mechanisms and individual or family factors could be also involved. Appearance circumstances are more various than first expected. The concept of serotonin syndrome seems to bring together entities that differ in physiopathology and seriousness, and we propose to distinguish between serotonin syndrome and other types of syndromes. Knowing serotonin syndrome is useful both for prevention and for recognizing it as a potentially lethal emergency.

Pharmacokinetic interaction between multiple-dose venlafaxine and single-dose lithium

Venlafaxine is a structurally novel antidepressant. Because lithium and antidepressants may be administered concomitantly, it is important to determine whether the disposition of venlafaxine and lithium is affected by coadministration. An open-label study was conducted to evaluate the effects of multiple-dose, steady-state venlafaxine administration on the pharmacokinetics of a single oral dose of lithium. Analogously, the effects of administration of a single-dose of lithium on the disposition of venlafaxine and its active metabolite, O-desmethylvenlafaxine, after multiple-dose administration of venlafaxine were assessed. Administration of 600 mg lithium carbonate did not affect venlafaxine absorption. Lithium significantly reduced the renal clearance of venlafaxine from 0.053 to 0.027 L/h/kg. However, renal excretion is not a major elimination pathway for venlafaxine; thus, lithium did not affect the total clearance of venlafaxine. Lithium administration had similar effects on elimination of O-desmethylvenlafaxine. Multiple-dose administration of 50 mg of venlafaxine every 8 hours produced a slight increase in the rate of lithium absorption, but did not affect the extent of lithium absorption. Total clearance (0.026 L/h/kg) and steady-state volume of distribution (0.71 L/kg) of lithium were not affected by administration of venlafaxine. Thus, there were no clinically significant pharmacokinetic interactions between venlafaxine and lithium.

Managing selective serotonin reuptake inhibitor-drug interactions in clinical practice

Combination drug therapy is common in psychiatry. It plays a role in the treatment of patients with multiple disorders, in the management of residual symptoms or resistant disease, and in the alleviation of unwanted effects of the primary drug. Coadministration of psychotropic drugs with medications for medical illnesses is becoming more common as well, because as many as half the patients with major depression require long term treatment, and because the number of patients who are elderly is increasing as the population ages. To safely manage multidrug regimens, the clinician must be knowledgeable about drug-drug interaction potential. Drug-drug interactions can produce a change in the pharmacological effect of a drug by altering activity at the site of action (a pharmacodynamic interaction), or by changing the plasma concentrations of a drug (a pharmacokinetic interaction), or both. Selective serotonin reuptake inhibitors (SSRIs) have the potential to impair the oxidative metabolism of several drugs, including tricyclic antidepressants and neuroleptics. However, the SSRIs highlight the maxim that overgeneralisation can be as detrimental to rational co-pharmacy as ignorance of interaction potential. The SSRIs differ in terms of which other drugs they affect, which patients are at risk, and to what extent the effect is clinically important. Clinicians must assess drug combinations on a case-by-case basis. Standard management practices of dose titration, monitoring plasma drug concentrations when the therapeutic index is narrow, and observing for adverse events minimise the clinical impact of potential drug-drug interactions.

Selective serotonin reuptake inhibitors: pharmacologic profiles and potential therapeutic distinctions

OBJECTIVE

To review the respective pharmacologic profiles of the selective serotonin reuptake inhibitors (SSRIs), with particular emphasis placed on clinically relevant distinctions.

DATA SOURCES

A MEDLINE search was conducted to identify English language literature published within the last five years on the four SSRIs (fluoxetine, sertraline, paroxetine, fluvoxamine). Previous review articles were scrutinized for additional citations, and manufacturers provided a contemporary bibliography of more recent material.

STUDY SELECTION/DATA EXTRACTION

Studies were selected for specific citation on the basis of comparative research merit and the contribution of this original literature to the pharmacologic profile(s) described.

DATA SYNTHESIS

All SSRIs appear to be more efficacious than placebo for the acute treatment of major depressive disorder (MDD). Short-term (six-week) efficacy was comparable with that of tricyclic antidepressants for the amelioration of MDD regarded as moderate in severity. Further comparative trials are clearly indicated to demonstrate the therapeutic benefits of SSRIs in specific populations (e.g., geriatric, severely ill) and to demonstrate sustained benefit with long-term prophylaxis. Other potential indications for SSRIs include obsessive-compulsive disorder, panic disorder, bulimia, and chronic pain syndromes. Pharmacokinetic profiles of the four SSRIs reveal similar parametric values, and most quantitative differences are of limited clinical significance. Adverse effects are common but ordinarily mild and transient, primarily restricted to the gastrointestinal tract and central nervous system. Important differences in the prevalence or severity of these adverse effects await the accumulation of further clinical experience and the completion of additional comparative trials. Similarly, the relative propensity of SSRIs to inhibit the metabolism of other medications is currently under investigation.

CONCLUSIONS

The four SSRIs studied appear to be more similar than they are different. Slowly, important distinctions are beginning to emerge with regard to adverse effect profiles and potential drug interactions. Given that the costs of these respective medications are comparable, such differences may ultimately serve to establish the preferential selection of individual agents in specific clinical situations.

Lithium side effects in the medically ill

OBJECTIVE

This review will include the general pharmacology of lithium and discuss its effects on various organ systems, with emphasis on the medically ill patient as well as the geriatric patient with multiple medical problems.

METHODS

A full literature review on the side effects of lithium was performed. Attention is focused on the medically ill and possible drug interactions.

RESULTS

This review points to the numerous problems which can result in toxicity in the medically ill or the geriatric patient.

CONCLUSION

Serious side effects can be avoided with proper drug monitoring and knowledge of potential drug interactions.

Sertraline does not alter steady-state concentrations or renal clearance of lithium in healthy volunteers

An open-label, placebo-controlled study was conducted to determine the effects of sertraline on the steady-state levels and renal clearance of lithium in 20 healthy volunteers. Subjects received 600 mg of lithium twice daily for 9 days. On the evening of day 8, subjects received orally either placebo or 100 mg of sertraline; these were administered twice, 8 hours apart, beginning 2 hours after the evening dose of lithium. In a comparison of day 8 with day 9 (before administration of the morning doses of lithium), sertraline was associated with only a 0.01 mEq/L (1.4%) decrease in steady-state levels and a 0.11 L/hour (6.9%) increase in the renal clearance of lithium. Neither change was statistically significant relative to placebo. Four subjects were excluded from analysis because of protocol violations or laboratory abnormalities unrelated to sertraline. Seven subjects who received lithium plus sertraline experienced side effects, mainly tremors, possibly related to treatment, whereas none of those administered lithium plus placebo experienced side effects. No sertraline-related laboratory abnormalities were observed.

Fluoxetine-induced suicidality, serotonin, and seasonality

In spite of the complexities involved in suicide, fluoxetine has been prematurely and simplistically blamed for inducing this phenomenon. A variety of variables must be factored into such an interpretation. Nevertheless, given the complicated psychobiological circumstances involved, acute and rapid changes in serotonin (5-HT) function appear to be important to the understanding of changes in suicidal behavior. Such a mechanism may also explain the robust seasonal peak of suicides in spring.

Adverse effects and drug interactions associated with fluoxetine therapy

Fluoxetine, an inhibitor of serotonin reuptake, was released by the Food and Drug Administration in 1988 and was among the most prescribed drugs for that year. Although fluoxetine has been promoted as a safe antidepressant, a recent literature search revealed a number of case reports of adverse effects and drug interactions attributed to its use. This review familiarizes healthcare professionals with some of the currently known interactions and adverse effects and suggests ways of avoiding such events in clinical practice.