QTc prolongation and torsades de pointes in an elderly woman taking fluoxetine

Cardiovascular toxicity induced by SSRIs: Analysis of spontaneous reports submitted to FAERS

Depression diagnoses have surged recently, and selective serotonin reuptake inhibitors (SSRIs) are the go-to treatment. However, studies indicate that long-term use of SSRIs can increase cardiovascular risk without systematic evaluation of the drug class. To offer clinical guidance, we performed an evaluation of the association between the six most commonly prescribed SSRIs and cardiovascular adverse events. Using the FDA Adverse Event Reporting System (FAERS) from Q1 2004 to Q2 2022, we conducted a disproportionality analysis and determined the magnitude of significant signals using statistical shrinkage transformations. Our study revealed that arrhythmias, torsades de pointes/QT prolongation, cardiomyopathy, and hypertension were among the most prevalent adverse events linked to SSRIs. Our analysis also showed a significant association between SSRIs and the aforementioned adverse events, with higher incidence in middle-aged and elderly patients and women. We further observed a rising trend in the incidence of arrhythmias, torsades de pointes/QT prolongation, and hypertension, highlighting the need for heightened cardiac monitoring in patients on SSRIs.

Oxytocin exerts harmful cardiac repolarization prolonging effects in drug-induced LQTS

Background

Oxytocin is used therapeutically in psychiatric patients. Many of these also receive anti-depressant or anti-psychotic drugs causing acquired long-QT-syndrome (LQTS) by blocking HERG/I_Kr. We previously identified an oxytocin-induced QT-prolongation in LQT2 rabbits, indicating potential harmful effects of combined therapy. We thus aimed to analyze the effects of dual therapy with oxytocin and fluoxetine/risperidone on cardiac repolarization.

Methods

Effects of risperidone, fluoxetine and oxytocin on QT/QTc, short-term variability (STV) of QT, and APD were assessed in rabbits using in vivo ECG and ex vivo monophasic AP recordings in Langendorff-perfused hearts. Underlying mechanisms were assessed using patch clamp in isolated cardiomyocytes.

Results

Oxytocin, fluoxetine and risperidone prolonged QTc and APD in whole hearts. The combination of fluoxetine + oxytocin resulted in further QTc- and APD-prolongation, risperidone + oxytocin tended to increase QTc and APD compared to monotherapy. Temporal QT instability, STV_QTc was increased by oxytocin, fluoxetine / fluoxetine + oxytocin and risperidone / risperidone + oxytocin. Similar APD-prolonging effects were confirmed in isolated cardiomyocytes due to differential effects of the compounds on repolarizing ion currents: Oxytocin reduced I_Ks, fluoxetine and risperidone reduced I_Kr, resulting in additive effects on I_Ktotal-tail. In addition, oxytocin reduced I_K1, further reducing the repolarization reserve.

Conclusion

Oxytocin, risperidone and fluoxetine prolong QTc / APD. Combined treatment further prolongs QTc/APD due to differential effects on I_Ks and I_K1 (block by oxytocin) and I_Kr (block by risperidone and fluoxetine), leading to pronounced impairment of repolarization reserve. Oxytocin should be used with caution in patients in the context of acquired LQTS.

Evaluating the risk of QTc prolongation associated with antidepressant use in older adults: a review of the evidence

Antidepressants are widely used medications for a range of medical conditions such as mood disorders and chronic pain in older adults. A vast body of evidence exists concerning the risks of QT interval prolongation associated with these agents and healthcare providers should critically evaluate the potential for QT prolongation when selecting antidepressant agents. Long QT syndrome is a disorder of myocardial repolarization that manifests as a prolonged QT interval on an electrocardiogram (ECG) and has been demonstrated to increase with age. The objective of this review is to present and evaluate existing literature regarding the risk of QT prolongation in older adults, age 60 years and older, and discuss the implications for clinical practice. A PubMed search was conducted to identify studies evaluating the QT prolonging effects of antidepressant medications and publications were chosen based on pertinent criteria. Depending on the antidepressant agent and patient-specific factors, clinicians should assess and monitor electrolytes and EGCs to evaluate the risks and benefits for older adults receiving agents known to prolong the QT interval.

QTc prolongation and torsades de pointes due to a coadministration of fluoxetine and amiodarone in a patient with implantable cardioverter-defibrillator: Case report and review of the literature

RATIONALE

Drug-induced prolongation of the corrected QT interval (QTc) may lead to serious and potentially life-threatening ventricular tachyarrhythmia, such as torsades de pointes (Tdp), which is worthy of clinical attention. Here, we report 1 case of Tdp after a coadministration of fluoxetine and amiodarone.

PATIENT CONCERNS

A 62-year-old Chinese male who placed with the implanted cardioverter-defibrillator (ICD) appeared the QTc prolongation and Tdp after the concurrent administration of fluoxetine and amiodarone.

DIAGNOSES

Torsades de pointes (Tdp).

INTERVENTIONS

The patient was treated with magnesium and potassium immediately. Her ICD-brady pacing mode was reprogrammed to 90 bpm. Meanwhile, both of fluoxetine and amiodarone were discontinued.

OUTCOMES

The further episodes of Tdp were prevented. After a few days, the QTc gradually decreased without clinically significant arrhythmias.

LESSONS

The present case demonstrates that a potential drug-drug interaction (DDI) may lead to a life-threatening drug adverse reaction (ADR) especially in special subjects. Therefore, clinicians should closely monitor the electrocardiogram (ECG) when QTc-prolonging agents are given to patients with cardiac abnormalities, and avoid combining 2 QTc-prolonging drugs.

Cardiovascular adverse reactions during antidepressant treatment: a drug surveillance report of German-speaking countries between 1993 and 2010

BACKGROUND

Antidepressants (ADs) are known to have the potential to cause various cardiovascular adverse drug reactions (ADRs). The tricyclic antidepressants (TCAs) were first revealed to be a possible source of cardiovascular ADRs. In recent years, newer classes of ADs were also suggested to have a higher risk of cardiovascular adverse effects. In particular, the selective serotonin reuptake inhibitors (SSRIs) were suspected to have the potential to induce QTc interval prolongation, and therefore increase the risk of ventricular arrhythmia. This descriptive study is based on the continuous pharmacovigilance program of German-speaking countries (Austria, Germany, and Switzerland), the Arzneimittelsicherheit in der Psychiatrie (AMSP), which assesses severe ADRs occurring in clinical routine situations.

METHODS

Of 169,278 psychiatric inpatients treated with ADs between 1993 and 2010, 198 cases of cardiovascular ADRs (0.12%) were analyzed.

RESULTS

Our study showed that the incidence rates of cardiovascular ADRs were highest during treatment with monoamine oxidase inhibitors (0.27%), TCAs (0.15%), and serotonin noradrenaline reuptake inhibitors (0.14%); the risk of occurring during treatment with SSRIs (0.08%) was significantly lower. The noradrenergic and specific serotonergic AD mirtazapine (0.07%) had a significantly lower risk of cardiovascular ADRs than all other ADs. Severe hypotension was the most frequent ADR, followed by hypertension, arrhythmia, and in some rare cases heart failure.

CONCLUSIONS

Despite certain limitations due to the AMSP study design, our observations on cardiovascular ADRs can contribute to a better knowledge of the cardiovascular risk profiles of antidepressants in the clinical routine setting. However, prospective studies are needed to verify our findings.

QTc interval prolongation and torsade de pointes associated with second-generation antipsychotics and antidepressants: a comprehensive review

We comprehensively reviewed published literature to determine whether it supported the link between corrected QT (QTc) interval prolongation and torsade de pointes (TdP) for the 11 second-generation antipsychotics and seven second-generation antidepressants commonly implicated in these complications. Using PubMed and EMBASE, we identified four thorough QT studies (one each for iloperidone, ziprasidone, citalopram, and escitalopram), 40 studies specifically designed to assess QTc interval prolongation or TdP, 58 publications based on data from efficacy and safety trials, 18 toxicology studies, and 102 case reports. Thorough QT studies, QTc prolongation-specific studies, and studies based on efficacy and safety trials did not link drug-associated QTc interval prolongation with TdP. They only showed that the drugs reviewed caused varying degrees of QTc interval prolongation, and even that information was not clear and consistent enough to stratify individual drugs for this risk. The few toxicology studies provided valuable information but their findings are pertinent only to situations of drug overdose. Case reports were most informative about the drug-QTc interval prolongation-TdP link. At least one additional well established risk factor for QTc prolongation was present in 92.2 % of case reports. Of the 28 cases of TdP, six (21.4 %) experienced it with QTc interval <500 ms; 75 % of TdP cases occurred at therapeutic doses. There is little evidence that drug-associated QTc interval prolongation by itself is sufficient to predict TdP. Future research needs to improve its precision and broaden its scope to better understand the factors that facilitate or attenuate progression of drug-associated QTc interval prolongation to TdP.

Selective serotonin reuptake inhibitors and torsade de pointes: new concepts and new directions derived from a systematic review of case reports

OBJECTIVE

In the light of the recent United States Food and Drug Administration (FDA) warning to clinicians on using previously approved doses of citalopram because of the purported higher risk of torsade de pointes (TdP), we pursued the broader question: are selective serotonin reuptake inhibitor (SSRI) antidepressant agents as a group unsafe because they might induce QTc interval prolongation and TdP?

METHOD

We reviewed the literature and found only 15 case reports (6 of fluoxetine, 1 of sertraline and 8 of citalopram) of SSRI-associated QTc interval prolongation linking to TdP.

RESULTS

A total of 13 cases contained sufficient information for analysis. In the setting of TdP, QTc interval prolongation does not clearly relate to SSRI dose.

CONCLUSION

Applying conventional statistics as the FDA does may not be the best tool to study this phenomenon because SSRI-associated TdP is a very rare event and hence best understood as an 'extreme outlier'. Despite the limitations inherent in case report material, case reports on drug-associated QTc interval prolongation and TdP provide valuable information that should be considered along with other sources of information for clinical guidance.

A comparison of the risk of QT prolongation among SSRIs

OBJECTIVE

To report QT prolongation potential in selective serotonin reuptake inhibitors (SSRIs) in order to advise clinicians on safe use of SSRIs other than citalopram in light of citalopram warnings.

DATA SOURCES

Primary literature and case reports were identified through a systematic search. Data from drug manufacturers, package inserts, and the ArizonaCERT database were also utilized.

STUDY SELECTION AND DATA EXTRACTION

English-language studies and case reports were included.

DATA SYNTHESIS

Studies demonstrate possible dose-related clinically significant QT prolongation with escitalopram. Fluoxetine, fluvoxamine, and sertraline at traditional doses demonstrate a lack of clinically significant increases in QTc in the majority of studies. Further, paroxetine monotherapy shows a lack of clinically significant QTc prolongation in all studies. However, case reports or reporting tools still link these SSRIs with QTc prolongation. Fluoxetine, escitalopram, and sertraline used in post-acute coronary syndrome patients did not demonstrate risk of QTc prolongation.

CONCLUSION

For clinicians who choose not to use citalopram due to recent Food and Drug Administration (FDA) recommendations, other antidepressants within this class may be considered. When citalopram is not utilized based on risk factors for TdP, use of escitalopram is not likely the safest alternative. Based on current literature, fluoxetine, fluvoxamine, and sertraline appear to have similar, low risk for QT prolongation, and paroxetine appears to have the lowest risk. However, there are significant limitations in interpreting the studies, including varying definitions of significant QT prolongation. Therefore, choice of an alternative SSRI should be based on individual risk factors for arrhythmias and other patient-specific factors.

WCD LifeVest: risk stratification in a case of Tako-Tsubo cardiomyopathy with QT interval prolongation

A 50-year-old woman with arterial hypertension suffered from recurrent syncope. On admission, recurrent torsades de pointes tachycardia, ventricular flutter, and ventricular fibrillation with the necessity of cardiopulmonary resuscitation were documented. After administration of β-blocking agents, amiodarone, and magnesium, heart rhythm was stabilized. Coronary angiography excluded coronary artery disease. Echocardiography revealed apical ballooning with reduced ventricular function. The ECG showed left bundle-branch block and profound QT prolongation. A WCD (wearable cardioverter-defibrillator) LifeVest was prescribed for the patient, and, thereafter, no arrhythmias were experienced. The ECG gradually normalized; echocardiography revealed slight anteroapical hypokinesia with overall normal left ventricular function. After a period of 3 months, the patient was no longer asked to wear the LifeVest; 6 months later the patient is without any complaints.

Proarrhythmic risk with antipsychotic and antidepressant drugs: implications in the elderly

The quinidine-like effects of some antidepressant drugs (particularly tricyclic antidepressants) and many antipsychotic drugs (particularly the phenothiazines) confound treatment of psychosis and depression in patients with major mental illness. This is especially true among elderly patients with existing risk factors for corrected QT (QTc) interval prolongation. We used PubMed, previously reported review articles and the extensive personal files of the authors to identify cases of subjects aged>or=60 years who developed QTc interval prolongation, polymorphic ventricular tachycardia (PVT)/torsade de pointes (TdP) and/or sudden cardiac death while taking antipsychotic or antidepressant drugs or a combination of these medications. We identified 37 patients who had taken, in total, 46 antipsychotic or antidepressant drugs. Our most striking finding was that almost four-fifths of our cases involved women. When the 14 critically ill subjects receiving haloperidol intravenously were excluded, 91.3% of our subjects were women. Almost three-quarters of our study subjects had cardiovascular disease. Intravenous administration of haloperidol in the critically ill and profoundly agitated elderly warrants particular comment. Of the 14 subjects in this category identified, six were men and eight were women. In 13 cases, the drug dose far exceeded the 2 mg necessary to produce an antipsychotic effect. These clinicians were using an agent to achieve sedation that usually requires very high doses in the critically ill and profoundly agitated elderly to achieve this effect. Inclusion criteria for our literature review required antipsychotic and/or antidepressant drug-induced QTc interval prolongation. Even so, our finding that 31 of our 37 subjects developed PVT is sobering. However, the reader should not conclude that drug-induced QTc interval prolongation is highly predictive of PVT or its TdP subtype. All of our study subjects had at least two risk factors for TdP, with age and sex being the most common. We included the rare case of a patient with congenital long QT syndrome who developed further lengthening of the QTc interval and TdP when prescribed an antidepressant drug well known to produce QTc interval prolongation. We conclude with recommendations for clinicians not expert in the specialty of cardiology to deal with the many questions raised in this review. Specifically, such clinicians treating elderly patients with antipsychotic and antidepressant drugs that may prolong the QTc interval should aggressively obtain a baseline ECG for elderly female patients with additional risk factors such as personal or family history of pre-syncope or syncope, electrolyte disturbances or cardiovascular disease. Elderly male patients are also subject to QTc interval prolongation when such risk factors are present. It is important that the clinicians themselves inspect ECGs. If the QT interval is more than half the RR interval, QTc interval prolongation is likely to be present. In such cases, a cardiology colleague interested in QTc interval issues and TdP should be asked to review the ECG. Finally, nothing in our recommendations replaces meticulous attention to US FDA guidelines in the package insert of each drug.

Impact and clinical management of depression in patients with coronary artery disease

The rates of major adverse coronary events, including recurrent ischemic events and death, in patients with coronary artery disease (CAD) have been shown to be significantly increased in patients with depression. In addition, health care costs are higher and health-related quality of life is lower in depressed patients with CAD. Several pathophysiologic mechanisms have been proposed for the association of increased events seen in this population. Studies have focused on antidepressants (specifically, selective serotonin reuptake inhibitors and mirtazapine), psychotherapy (cognitive behavioral therapy and interpersonal psychotherapy), and a wide range of other nonpharmacologic interventions. Pharmacologic and nonpharmacologic treatments are known to improve depressive symptoms in patients with CAD, but their effects on outcomes such as mortality and hospital admissions remain controversial. If treatment of depression is warranted, strategies should include sertraline or citalopram, with or without cognitive behavioral therapy, based on the known efficacy and safety of the drugs in this population. Nonpharmacologic therapy such as aerobic exercise has been shown to improve not only depression but also cardiovascular health. When selecting an appropriate antidepressant, clinicians should consider their patients' comorbid conditions and the potential for drug interactions, and treatment should be frequently monitored. Screening for depression in patients with cardiac disease should be instituted on a routine basis by using either case-finding or symptom-triggered approaches. Based on the high prevalence of depression and its known adverse effects in patients with CAD, future research is needed to help determine the role of antidepressants and nonpharmacologic strategies in improving outcomes in patients with both comorbidities.

Depression and risk of sudden cardiac death and coronary heart disease in women: results from the Nurses' Health Study

OBJECTIVES

We assessed the association between depression and sudden cardiac death (SCD) and cardiac events among individuals without baseline coronary heart disease (CHD).

BACKGROUND

Depression is a risk factor for cardiac events and mortality among those with CHD, possibly from arrhythmia.

METHODS

We studied depressive symptoms and a proxy variable for clinical depression consisting of severe symptoms and/or antidepressant medication use and their relationship to cardiac events in the Nurses' Health Study. Questionnaires in 1992, 1996, and 2000 assessed symptoms with the Mental Health Index (MHI-5), and antidepressant use was assessed in 1996 and 2000. Primary end points included SCD, fatal CHD, and nonfatal myocardial infarction.

RESULTS

Among 63,469 women without prior CHD/stroke in 1992, 7.9% had MHI-5 scores <53, previously found to predict clinical depression. Depressive symptoms were associated with CHD events, and the relationship was strongest for fatal CHD, where the association remained significant even after controlling for CHD risk factors (hazard ratio [HR]: 1.49; 95% confidence interval [CI]: 1.11 to 2.00 for MHI-5 score <53). In models from 1996 onward, our proxy variable for clinical depression was most associated with SCD in multivariable models (HR: 2.33, 95% CI: 1.47 to 3.70), and this risk was primarily due to a specific relationship between antidepressant use and SCD (HR: 3.34, 95% CI: 2.03 to 5.50).

CONCLUSIONS

In this cohort of women without baseline CHD, depressive symptoms were associated with fatal CHD, and a measure of clinical depression including antidepressant use was specifically associated with SCD. Although antidepressant use might be a marker of worse depression, its specific association with SCD merits further study.

Electrophysiological changes of cardiac function during antidepressant treatment

Some antidepressant agents can cause electrophysiological changes of cardiac function leading to ventricular arrhythmias and sudden death. However, antidepressants have also protective effects on the heart through their capacity to modulate cardiac autonomic-mediated physiological responses. Heart rate variability and QTc length are two strictly linked parameters that allow us to appreciate the effects of different drugs on cardiac physiology. Heart rate variability reflects functioning of the autonomic nervous system and possibly also regulation by the limbic system. Autonomic regulation of cardiac activity influences also cardiac repolarization and QT length, both directly and via its effects on heart rate. In this review we present the methodologies adopted to study the effect of antidepressant drugs on QT length and heart rate variability and we summarize data on electrophysiological changes related to antidepressant treatment. Clinical implications for the choice of different antidepressants in different clinical populations are discussed.

Antenatal use of selective serotonin-reuptake inhibitors and QT interval prolongation in newborns

OBJECTIVES

Prolongation of the QT interval is a risk factor for sudden death. Selective serotonin-reuptake inhibitor antidepressants can prolong the QT interval and are widely used by pregnant women. Whether antenatal exposure to selective serotonin-reuptake inhibitor causes QT prolongation in offspring is unknown. The aim of this study was to determine the effect of maternal use of selective serotonin-reuptake inhibitor antidepressants during pregnancy on the QTc interval of the offspring.

METHODS

Between January 2000 and December 2005, we collected data on all of the newborns born at a single tertiary care hospital. Electrocardiograms of infants exposed to selective serotonin-reuptake inhibitor antidepressants in utero were compared with those of healthy control newborns matched on gestational age. The tracings were interpreted by a pediatric cardiologist who was unaware of the drug exposure.

RESULTS

We identified 52 newborns exposed to selective serotonin-reuptake inhibitor antidepressants in the immediate antepartum period and 52 matched control subjects. The mean QTc was significantly longer in the group of newborns exposed to antidepressants as compared with control subjects (409 +/- 42 vs 392 +/- 29 milliseconds). Five (10%) newborns exposed to selective serotonin-reuptake inhibitor antidepressants had a markedly prolonged QTc interval (>460 milliseconds) compared with none of the unexposed newborns. The longest QTc interval observed among exposed newborns was 543 milliseconds. All of the drug-associated repolarization abnormalities normalized in subsequent electrocardiographic tracings.

CONCLUSIONS

Antepartum use of selective serotonin-reuptake inhibitor antidepressants is associated with QTc interval prolongation in exposed neonates. Additional research using a standardized protocol is needed to determine whether exposure to selective serotonin-reuptake inhibitor antidepressants in late pregnancy is also associated with arrhythmias.

The QT interval and psychotropic medications in children: recommendations for clinicians

The use of psychotropic medications in children has increased significantly in the last few years. There have been several case reports of sudden death in children taking specific psychotropic medications. Fears that these deaths might have been caused by ventricular arrhythmias have been enhanced by reports of electrocardiographic abnormalities, including prolongation of the QTc interval, in patients taking these medications. Several factors including genetic susceptibility, pre-existing cardiac disease, abnormalities of drug clearance and concomitant use of other medications known to affect the QTc interval can increase the susceptibility of the heart to conduction abnormalities. This article discusses the potential of particular psychotropic drugs to prolong the QTc interval in children, and examines other factors that may contribute to conduction abnormalities. We aim to provide clear clinical recommendations for the prescription of these drugs and the monitoring of children taking them.

Drug-induced long QT syndrome: hERG K+ channel block and disruption of protein trafficking by fluoxetine and norfluoxetine

BACKGROUND AND PURPOSE

Fluoxetine (Prozac) is a widely prescribed drug in adults and children, and it has an active metabolite, norfluoxetine, with a prolonged elimination time. Although uncommon, Prozac causes QT interval prolongation and arrhythmias; a patient who took an overdose of Prozac exhibited a prolonged QT interval (QTc 625 msec). We looked for possible mechanisms underlying this clinical finding by analysing the effects of fluoxetine and norfluoxetine on ion channels in vitro.

EXPERIMENTAL APPROACH

We studied the effects of fluoxetine and norfluoxetine on the electrophysiology and cellular trafficking of hERG K+ and SCN5A Na+ channels heterologously expressed in HEK293 cells.

KEY RESULTS

Voltage clamp analyses employing square pulse or ventricular action potential waveform protocols showed that fluoxetine and norfluoxetine caused direct, concentration-dependent, block of hERG current (IhERG). Biochemical studies showed that both compounds also caused concentration-dependent reductions in the trafficking of hERG channel protein into the cell surface membrane. Fluoxetine had no effect on SCN5A channel or HEK293 cell endogenous current. Mutations in the hERG channel drug binding domain reduced fluoxetine block of IhERG but did not alter fluoxetine's effect on hERG channel protein trafficking.

CONCLUSIONS AND IMPLICATIONS

Our findings show that both fluoxetine and norfluoxetine at similar concentrations selectively reduce IhERG by two mechanisms, (1) direct channel block, and (2) indirectly by disrupting channel protein trafficking. These two effects are not mediated by a single drug binding site. Our findings add complexity to understanding the mechanisms that cause drug-induced long QT syndrome.

Combined hERG channel inhibition and disruption of trafficking in drug-induced long QT syndrome by fluoxetine: a case-study in cardiac safety pharmacology

Drug-induced prolongation of the rate-corrected QT interval (QTCI) on the electrocardiogram occurs as an unwanted effect of diverse clinical and investigational drugs and carries a risk of potentially fatal cardiac arrhythmias. hERG (human ether-à-go-go-related gene) is the gene encoding the alpha-subunit of channels mediating the rapid delayed rectifier K+ current, which plays a vital role in repolarising the ventricles of the heart. Most QTCI prolonging drugs can inhibit the function of recombinant hERG K+ channels, consequently in vitro hERG assays are used widely as front-line screens in cardiac safety-testing of novel chemical entities. In this issue, Rajamani and colleagues report a case of QTCI prolongation with the antidepressant fluoxetine and correlate this with a dual effect of the drug and of its major metabolite norfluoxetine on hERG channels. Both compounds were found to produce an acute inhibition of the hERG channel by pharmacological blockade, but in addition they also were able to disrupt the normal trafficking of hERG protein to the cell membrane. Mutations to a key component of the drug binding site in the S6 region of the channel greatly attenuated channel block, but did not impair disruption of trafficking; this suggests that channel block and drug effects on trafficking were mediated by different mechanisms. These findings add to growing evidence for disruption of hERG channel trafficking as a mechanism for drug-induced long QT syndrome and raise questions as to possible limitations of acute screening methods in the assessment of QTcI prolonging liability of drugs in development.