A critical evaluation of the cardiac toxicity of citalopram: part 2

Antidepressants and the risk of arrhythmia in elderly affected by a previous cardiovascular disease: a real-life investigation from Italy

PURPOSE

The study aimed to fill existing knowledge gaps on the safety of antidepressant drugs (ADs) by estimating the risk of hospitalization for arrhythmia associated with use of selective serotonin reuptake inhibitors (SSRIs) and newer atypical ADs (NAAs) among elderly with previous cardiovascular (CV) events.

METHODS

The cohort was composed by 199,569 individuals aged ≥ 65 years from five Italian healthcare territorial units who were discharged for cardiovascular outcomes in the years 2008-2010. The 17,277 patients who experienced hospital admission for arrhythmia during follow-up were included as cases. Odds of current ADs use among cases (i.e., 14 days before hospital admission) was compared with (i) odds of current use of 1:5 matched controls (between-patients case-control) and with (ii) odds of previous use during 1:5 matched control periods (within-patient case-crossover). The risk of arrhythmia associated with ADs current use was modelled fitting a conditional logistic regression. A set of sensitivity analyses was performed to account for sources of systematic uncertainty.

RESULTS

Current users of SSRIs and NAAs were at increased risk of arrhythmia with case-control odds ratios (OR) of 1.37 (95% confidence interval, CI 1.18 to 1.58) and 1.41 (1.16 to 1.71) and case-crossover OR of 1.48 (1.20 to 1.81) and 1.72 (1.31 to 2.27). An increased risk of arrhythmia was associated with current use of trazodone (NAA) consistently in case-control and case-crossover designs.

CONCLUSIONS

Evidence that current use of SSRIs and NAAs is associated to an increased risk of arrhythmia among elderly with CV disease was consistently supplied by two observational approaches.

High-Dose Citalopram and Escitalopram and the Risk of Out-of-Hospital Death

OBJECTIVE

Studies demonstrating that higher doses of citalopram (> 40 mg) and escitalopram (> 20 mg) prolong the corrected QT interval prompted regulatory agency warnings, which are controversial, given the absence of confirmatory clinical outcome studies. We compared the risk of potential arrhythmia-related deaths for high doses of these selective serotonin reuptake inhibitors (SSRIs) to that for equivalent doses of fluoxetine, paroxetine, and sertraline.

METHODS

The Tennessee Medicaid retrospective cohort study included 54,220 persons 30-74 years of age without cancer or other life-threatening illness who were prescribed high-dose SSRIs from 1998 through 2011. The mean age was 47 years, and 76% were female. Demographic characteristics and comorbidity for individual SSRIs were comparable. Because arrhythmia-related deaths are typically sudden and occur outside the hospital, we analyzed out-of-hospital sudden unexpected death as well as sudden cardiac deaths, a more specific indicator of proarrhythmic effects.

RESULTS

The adjusted risk of sudden unexpected death for citalopram did not differ significantly from that for the other SSRIs. The respective hazard ratios (HRs) for citalopram versus escitalopram, fluoxetine, paroxetine, and sertraline were 0.84 (95% CI, 0.40-1.75), 1.24 (95% CI, 0.75-2.05), 0.75 (95% CI, 0.45-1.24), and 1.53 (95% CI, 0.91-2.55). There were no significant differences for sudden cardiac death or all study deaths, nor were there significant differences among high-risk patients (≥ 60 years of age, upper quartile baseline cardiovascular risk). Escitalopram users had no significantly increased risk for any study end point.

CONCLUSIONS

We found no evidence that risk of sudden unexpected death, sudden cardiac death, or total mortality for high-dose citalopram and escitalopram differed significantly from that for comparable doses of fluoxetine, paroxetine, and sertraline.

Antidepressant Controlled Trial For Negative Symptoms In Schizophrenia (ACTIONS): a double-blind, placebo-controlled, randomised clinical trial

BACKGROUND

Negative symptoms of schizophrenia represent deficiencies in emotional responsiveness, motivation, socialisation, speech and movement. When persistent, they are held to account for much of the poor functional outcomes associated with schizophrenia. There are currently no approved pharmacological treatments. While the available evidence suggests that a combination of antipsychotic and antidepressant medication may be effective in treating negative symptoms, it is too limited to allow any firm conclusions.

OBJECTIVE

To establish the clinical effectiveness and cost-effectiveness of augmentation of antipsychotic medication with the antidepressant citalopram for the management of negative symptoms in schizophrenia.

DESIGN

A multicentre, double-blind, individually randomised, placebo-controlled trial with 12-month follow-up.

SETTING

Adult psychiatric services, treating people with schizophrenia.

PARTICIPANTS

Inpatients or outpatients with schizophrenia, on continuing, stable antipsychotic medication, with persistent negative symptoms at a criterion level of severity.

INTERVENTIONS

Eligible participants were randomised 1 : 1 to treatment with either placebo (one capsule) or 20 mg of citalopram per day for 48 weeks, with the clinical option at 4 weeks to increase the daily dosage to 40 mg of citalopram or two placebo capsules for the remainder of the study.

MAIN OUTCOME MEASURES

The primary outcomes were quality of life measured at 12 and 48 weeks assessed using the Heinrich's Quality of Life Scale, and negative symptoms at 12 weeks measured on the negative symptom subscale of the Positive and Negative Syndrome Scale.

RESULTS

No therapeutic benefit in terms of improvement in quality of life or negative symptoms was detected for citalopram over 12 weeks or at 48 weeks, but secondary analysis suggested modest improvement in the negative symptom domain, avolition/amotivation, at 12 weeks (mean difference -1.3, 95% confidence interval -2.5 to -0.09). There were no statistically significant differences between the two treatment arms over 48-week follow-up in either the health economics outcomes or costs, and no differences in the frequency or severity of adverse effects, including corrected QT interval prolongation.

LIMITATIONS

The trial under-recruited, partly because cardiac safety concerns about citalopram were raised, with the 62 participants recruited falling well short of the target recruitment of 358. Although this was the largest sample randomised to citalopram in a randomised controlled trial of antidepressant augmentation for negative symptoms of schizophrenia and had the longest follow-up, the power of statistical analysis to detect significant differences between the active and placebo groups was limited.

CONCLUSION

Although adjunctive citalopram did not improve negative symptoms overall, there was evidence of some positive effect on avolition/amotivation, recognised as a critical barrier to psychosocial rehabilitation and achieving better social and community functional outcomes. Comprehensive assessment of side-effect burden did not identify any serious safety or tolerability issues. The addition of citalopram as a long-term prescribing strategy for the treatment of negative symptoms may merit further investigation in larger studies.

FUTURE WORK

Further studies of the viability of adjunctive antidepressant treatment for negative symptoms in schizophrenia should include appropriate safety monitoring and use rating scales that allow for evaluation of avolition/amotivation as a discrete negative symptom domain. Overcoming the barriers to recruiting an adequate sample size will remain a challenge.

TRIAL REGISTRATION

European Union Drug Regulating Authorities Clinical Trials (EudraCT) number 2009-009235-30 and Current Controlled Trials ISRCTN42305247.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 29. See the NIHR Journals Library website for further project information.

Risk of Ventricular Arrhythmia with Citalopram and Escitalopram: A Population-Based Study

Background

The risk of ventricular arrhythmia with citalopram and escitalopram is controversial. In this study we investigated the association between these two drugs and the risk of ventricular arrhythmia.

Methods

We conducted a population-based retrospective cohort study of older adults (mean age 76 years) from 2002 to 2012 in Ontario, Canada, newly prescribed citalopram (n = 137 701) or escitalopram (n = 38 436), compared to those prescribed referent antidepressants sertraline or paroxetine (n = 96 620). After inverse probability of treatment weighting using a propensity score, the baseline characteristics of the comparison groups were similar. The primary outcome was a hospital encounter with ventricular arrhythmia within 90 days of a new prescription, assessed using hospital diagnostic codes. The secondary outcome was all-cause mortality within 90 days.

Results

Citalopram was associated with a higher risk of a hospital encounter with ventricular arrhythmia compared with referent antidepressants (0.06% vs. 0.04%, relative risk [RR] 1.53, 95% confidence intervals [CI]1.03 to 2.29), and a higher risk of mortality (3.49% vs. 3.12%, RR 1.12, 95% CI 1.06 to 1.18). Escitalopram was not associated with a higher risk of ventricular arrhythmia compared with the referent antidepressants (0.03% vs. 0.04%, RR 0.84, 95% CI 0.42 to 1.68), but was associated with a higher risk of mortality (2.86% vs. 2.63%, RR 1.09, 95% CI 1.01 to 1.18).

Conclusion

Among older adults, initiation of citalopram compared to two referent antidepressants was associated with a small but statistically significant increase in the 90-day risk of a hospital encounter for ventricular arrhythmia.

The effectiveness and limitations of regulatory warnings for the safe prescribing of citalopram

Background

Citalopram is the most commonly prescribed antidepressant in Canada. Concerns have been raised about its cardiac safety, and a dose-dependent prolongation of the QT interval has been documented. Drug interactions involving concomitant use of other medications that prolong the QT interval or increase citalopram levels by interfering with its metabolism increase the cardiac risk. Regulatory bodies (Health Canada and the US Food and Drug Administration) issued warnings and required labeling changes in 2011/2012, suggesting maximum citalopram doses (<40 mg for those <65 years; <20 mg for those ≥65 years) and avoiding drug interactions that increase cardiac risk. The purpose of this study is to assess the impact of these warnings on citalopram prescribing practices.

Methods

A quasi-experimental interrupted time series analysis was conducted using all citalopram prescribing data from the population of Manitoba, Canada from 1999 to 2014. This allowed for the examination of high-dose prescribing (above regulatory warning levels) and the number of interacting medications per citalopram prescription.

Results

There was a dramatic decline in the prescribing of high doses in both age groups, with a 64.8% decline in those <65 years and 33.6% in those ≥65 years. Segmented regression models indicated significant breakpoints in the third quarter of 2011 for both age groups (P<0.0001), corresponding to the time the regulatory warnings were issued. There appeared to be no impact of the warnings on the prescribing of interacting medications. The number of interacting medications actually increased in the postwarning period (<65, 0.78–0.81 interactions per citalopram prescription; ≥65, 0.93–0.94, P<0.001).

Conclusion

Regulatory changes appear to have produced an important reduction in the high-dose prescribing of citalopram. In contrast to this relatively simple dosage change, there was no indication that the more complex issue of resolving drug–drug interactions was impacted by regulatory warnings.

Recognizing depression in late life

Depression presents differently in older adults than in younger adults and frequently occurs with many chronic illnesses in later life, though it is not a normal part of aging. The astute practitioner will screen for depression in this population and appropriately treat to improve chronic illness management and quality of life in older adults.

Implementation of warnings from Dear Doctor Letters (Rote-Hand-Briefe): an analysis of medication data from a large cohort of elderly patients

BACKGROUND

Dear Doctor Letters (also known as Direct Healthcare Professional Communications) inform physicians about significant newly discovered drug risks and about measures to take to reduce these risks. How far these warnings actually influence prescribing behavior is unclear.

METHOD

The Geriatrics in Bavaria-Database (GiB-DAT, Geriatrie in Bayern Datenbank) collects data from more than 50 centers offering inpatient geriatric health care. Based on GiB-DAT data, the discharge medication of 76 568 patients (81 ± 8 years, 67% women) was recorded in a standardized manner and analyzed for the implementation of information contained in two Dear Doctor Letters about the risks of dose-related or drug interaction-related QT interval prolongation caused by citalopram or escitalopram.

RESULTS

Patients were discharged with a median of 8 drugs. In the four quarters of 2012 following release of the Dear Doctor Letters, in comparison to the four quarters before their publication, a marked drop from 9.8% to 4.1% was seen in prescriptions for >20 mg/day citalopram--a dosage no longer recommended in elderly patients--and a similar drop from 23.6% to 12.8% in prescriptions for >10 mg/day escitalopram (p<0.0001). Co-prescription of either of these two drugs with other QT interval-prolonging drugs, which was now contraindicated, remained almost unchanged (citalopram: 19.3% [95% confidence interval (CI): 17.9-20.9%] versus 18.4% [95% CI: 17.0-19.8%]; escitalopram: 17.6% [95% CI: 15.8-19.6%] versus 17.1% [95% CI: 14.5-19.9%]).

CONCLUSION

Simple information in Dear Doctor Letters, such as a reduction of the maximum daily dose, was better implemented than complicated information regarding contraindicated co-medication. Quality assurance systems such as the GiB-DAT network make it possible to identify problems of this kind. Licensing authorities and pharmaceutical companies should should improve the clinical usability, e.g., by providing official reference lists of drugs with safety warnings.

Citalopram, QTc interval prolongation, and torsade de pointes. How should we apply the recent FDA ruling?

Recently, both the manufacturer of citalopram and the US Food and Drug Administration have warned health care providers and patients about new information implicating drug-induced QTc interval prolongation and torsade de pointes when using citalopram in doses >40 mg/day. This warning is not placed in the context of either benefits or risks in real-world clinical practice, leaving clinicians with an untenable choice between depriving patients of high-dose citalopram or malpractice litigation. We reviewed the literature and found no cases of citalopram-induced sudden cardiac death among patients taking up to 60 mg/day of citalopram and free of risk factors for QTc interval prolongation and torsade de pointes. Because psychotropic drug-induced sudden cardiac death is an outlier in the absence of identified risk factors for QTc interval prolongation and torsade de pointes, we do not believe current Phase 3 and Phase 4 studies provide sufficient information to limit current prescribing practices for citalopram (20 mg to 60 mg/day). We urge drug manufacturers and regulatory agencies to periodically publish full case reports of psychotropic drug-induced QTc interval prolongation, torsade de pointes, and sudden cardiac death so that clinicians and investigators may better understand the clinical implications of prescribing such drugs as citalopram.

Clinical use of antidepressant therapy and associated cardiovascular risk

A number of different psychotropic agents have been associated with an increased risk of cardiovascular disease, and these relationships have been difficult to interpret due to the presence of confounding factors. Recently, there has been renewed interest in the potential for certain antidepressants to cause QT prolongation, which is a predisposing factor for arrhythmia. However, the optimum means of determining QT remains contentious due to discrepancies between methods that may be readily applied in a clinical setting versus more detailed techniques during regulatory assessment. A number of different pharmacological mechanisms might explain the occurrence of adverse cardiac effects, and these differ according to the type of antidepressant agent. Emerging data indicate that citalopram exhibits a dose-effect relationship for QT prolongation. Whereas cardiotoxicity is readily apparent in the context of intentional antidepressant overdose, the occurrence of cardiac effects as a result of therapeutic administration is less certain. Pre-existing cardiac disease and other factors that independently predispose to arrhythmia are important considerations. Therefore, clinical judgment is needed to evaluate the overall risk or benefit of a particular antidepressant in any patient. Close monitoring should be considered for those at greatest risk of QT prolongation and arrhythmia.

FDA drug safety communications: a narrative review and clinical considerations for older adults

BACKGROUND

The US Food and Drug Administration (FDA) has new regulatory authorities intended to enhance drug safety monitoring in the postmarketing period. This has resulted in an increase in communication from the FDA in recent years about the safety profile of certain drugs. It is important to stay abreast of the current literature on drug risks to effectively communicate these risks to patients, other health care providers, and the general public.

OBJECTIVE

To summarize 4 new FDA drug safety communications by describing the evidence supporting the risks and the clinical implications for older adults.

METHODS

The FDA Web site was reviewed for new drug safety communications from May 2011 to April 2012 that would be relevant to older adults. Approved labeling for each drug or class was obtained from the manufacturer, and PubMed was searched for primary literature that supported the drug safety concern.

RESULTS

FDA drug safety communications for 4 drugs were chosen because of the potential clinical importance in older adults. A warning for citalopram was made because of potential problems with QT prolongation in patients taking less than 40 mg per day. The evidence suggests minor changes in QT interval. Given the flat dose-response curve in treating depression with citalopram, the new 20-mg/d maximum dose in older adults is sensible. Another warning was made for proton pump inhibitors (PPIs) and an increased risk of Clostridium difficile infection. A dose-response relationship was found for this drug risk. With C. difficile infections on the rise in older adults, along with other safety risks of PPI therapy, PPIs should only be used in older adults indicated for therapy for the shortest duration possible. In addition, a warning about dabigatran was made. There is strong evidence from a large clinical trial, as well as case reports, of increased bleeding risk in older adults taking dabigatran, especially in older adults with decreased renal function. This medication should be used with caution in older adults. Finally, several warnings were made about statins. Routine periodic monitoring of liver enzymes does not appear to be effective in detecting or preventing serious liver injury from statin use; thus, liver enzymes are no longer recommended to be routinely monitored. Statin-induced cognitive changes are rare, and insufficient evidence is currently available to establish causality. Statins appear to moderately increase the risk of developing diabetes (versus placebo), and regular screening for diabetes should be considered, especially for patients taking high-dose statins and patients with multiple risk factors for diabetes.

CONCLUSION

FDA drug safety communications incorporate complex methodologies that investigate the risks (and relative benefits) of medication therapy. Clinicians caring for older adults need to be aware of the most current evidence behind these drug risks to effectively communicate with and care for their patients.

A question about the potential cardiac toxicity of escitalopram

Previous reviews have focused on the potential cardiac toxicity of the racemic drug citalopram (Celexa(®)). Evaluating the safety of escitalopram (Lexapro(®)) is an important issue to consider, since it is the S-enantiomer of citalopram. Escitalopram has a small effect on the QTc interval. A prolonged QTc was seen in 2% to 14% of escitalopram overdose cases, without serious cardiac sequelae. The QTc prolongation effect of citalopram in beagle dogs has been attributed to the minor metabolite racemic didemethylcitalopram (DDCT). Whether the escitalopram minor metabolite S-DDCT has this effect is not known. Concentrations of S-DDCT are lower than DDCT, but for a broad range of doses of escitalopram and citalopram, the S-DDCT and DDCT concentrations are well below the QTc prolonging concentrations reported in dogs. There is no strong evidence from human and animal studies that the cardiac safety of escitalopram is significantly superior to that of citalopram.