Potassium, antipsychotic agents, arrhythmias, and sudden death

Two Sudden and Unexpected Deaths of Patients with Schizophrenia Associated with Intramuscular Injections of Antipsychotics and Practice Guidelines to Limit the Use of High Doses of Intramuscular Antipsychotics

Intravenous haloperidol has been associated with torsades de pointes (TdP). These two sudden deaths were probable adverse drug reactions (ADRs) following intramuscular (IM) antipsychotics. The autopsies described lack of heart pathology and were highly compatible with the possibility of TdP in the absence of risk factors other than the accumulation of antipsychotics with a high serum peak after the last injection, leading to death within hours. The first case was a 27-year-old African-American male with schizophrenia but no medical issues. His death was probably caused by repeated IM haloperidol injections of 10 mg (totaling 35 mg in 2 days). The second case involves a 42-year-old African-American female with metabolic syndrome. Her probable cause of death was the last ziprasidone IM injection of 20 mg in addition to (1) three extra haloperidol doses (2 hours before the ziprasidone injection, 5 mg oral haloperidol; approximately 21 hours earlier, 5 mg oral haloperidol; and 2 days prior, one 10 mg IM haloperidol injection), (2) 10 mg/day of scheduled oral haloperidol for 6 days before death, and (3) a long-acting paliperidone injection of 156 mg 18 days before death. The study of haloperidol glucuronidation and its impairment in some African-Americans is urgently recommended.

Risk of serious cardiac events in older adults using antipsychotic agents

BACKGROUND

Antipsychotic agents can lead to severe cardiovascular adverse events due to multiple mechanisms involving electrophysiologic and metabolic effects. Few epidemiologic studies have evaluated the risk of serious cardiovascular-related events in typical and atypical antipsychotic users.

OBJECTIVE

The purpose of this study was to compare the risk of serious cardiac events in older adults taking typical antipsychotics with those taking atypical antipsychotics.

METHODS

Prescription and medical information were derived from the IMS LifeLink Health Plan Claims database. The study involved a retrospective cohort of older adults (≥50 years) taking atypical or typical antipsychotics from July 1, 2000, to December 31, 2007. The primary outcome measure was hospitalization or emergency room visit due to serious cardiac events, including thromboembolism, myocardial infarction, cardiac arrest, and ventricular arrhythmias within 1 year after the index date. The 2 groups were matched on a propensity score to minimize the baseline differences between the groups. Survival analysis was conducted on the matched cohort to assess the risk of serious cardiovascular events in typical versus atypical users.

RESULTS

A total of 5580 patients were selected in each antipsychotic users group after propensity score matching. Serious cardiac events were found in 666 (11.9 %) atypical antipsychotic users and 698 (12.4%) typical antipsychotic users. Survival analysis revealed that typical antipsychotic users were at increased risk of serious cardiovascular events compared with atypical antipsychotic users (hazard ratio = 1.21; 95% CI, 1.04-1.40) after controlling for other factors.

CONCLUSIONS

Moderate increases in risk of serious cardiac events are associated with older adults using typical antipsychotic agents compared with atypical users. Health care professionals should carefully evaluate the benefit/risk ratio of antipsychotic agents before prescribing these agents to a vulnerable population.

High prevalence of hypokalemia in acute psychiatric inpatients

BACKGROUND

Hypokalemia is an easily identifiable, clinically important but commonly neglected condition in psychiatric patients. This study intended to examine the prevalence of hypokalemia and its clinical correlates in acute psychiatric inpatients.

METHOD

This retrospective study was conducted over a 6 month period in 2008. The case notes, computerized records and laboratory results of all patients who were consecutively admitted to the acute psychiatric wards in a University-affiliated regional psychiatric unit were studied.

RESULT

Three hundred forty-seven patients out of 440 admissions were studied. Hypokalemia, as defined by serum potassium level of less than 3.5 mmol/L, was found in 20.5% of patients with a higher prevalence in psychotic patients (27.7%). The mean potassium level of psychotic patients was lower than that of the overall study population (3.72 vs. 3.81 mmol/L, P<.05). White cell counts among the hypokalemic patients were higher than those without hypokalemia (7.8 vs. 7.1 x 10(9)/L, P=.02).

CONCLUSION

Hypokalemia was common among acute psychiatric inpatients. Both agitation and the use of antipsychotics were postulated to contribute to the high prevalence of hypokalemia among acutely ill psychiatric patients.

Factors affecting outcome in schizophrenia and their relevance for psychopharmacological treatment

A major focus of current treatment research in schizophrenia is the determinants of long-term outcome, including functional outcome and general medical well being, rather than just specific domains of psychopathology such as positive and negative symptoms, mood symptoms, and cognitive impairment. This focus does not negate the importance of the latter issues but sees them as factors contributing to long-term outcome to variable extents. A long-term treatment focus facilitates a more clinically relevant assessment of benefits versus risks of available treatments. For instance, atypical antipsychotic drugs as a group have clear advantages for several important domains of efficacy that may influence long-term outcome, but are also more expensive over the long term. Use of some agents may also result in deleterious physical health consequences as well as large additional costs over the long term owing to metabolic adverse effects. The present paper focuses on several key issues in schizophrenia which are important determinants of long-term outcome in schizophrenia, or influence choice of antipsychotic drugs, or both, including: (i) duration of untreated psychosis; (ii) impact of relapse on long-term outcome; (iii) limited efficacy for specific domains of psychopathology of current treatments; (iv) mortality owing to suicide; and (v) mortality owing to other causes (e.g. cardiovascular disease).

Possible role of potassium channel, big K in etiology of schizophrenia

Schizophrenia (SZ), a common severe mental disorder, affecting about 1% of the world population. However, the etiology of SZ is still largely unknown. It is believed that molecules that are in an association with the etiology and pathology of SZ are neurotransmitters including dopamine, 5-HT and gamma-aminobutyric acid (GABA). But several lines of evidences indicate that potassium large conductance calcium-activated channel, known as BK channel, is likely to be included. BK channel belongs to a group of ion channels that plays an important role in regulating neuronal excitability and transmitter releasing. Its involvement in SZ emerges as a great interest. For example, commonly used neuroleptics, in clinical therapeutic concentrations, alter calcium-activated potassium conductance in central neurons. Diazoxide, a potassium channel opener/activator, showed a significant superiority over haloperidol alone in the treatment of positive and general psychopathology symptoms in SZ. Additionally, estrogen, which regulates the activity of BK channel, modulates dopaminergic D2 receptor and has an antipsychotic-like effect. Therefore, we hypothesize that BK channel may play a role in SZ and those agents, which can target either BK channel functions or its expression may contribute to the therapeutic actions of SZ treatment.

Adverse cardiac effects associated with clozapine

OBJECTIVE

To review the published literature on serious adverse cardiac events associated with the atypical antipsychotic agent, clozapine, and to make recommendations for cardiac assessment of candidates for clozapine treatment and for monitoring of cardiac status after treatment is initiated.

DATA SOURCES

We searched the PubMed and MEDLINE databases for articles published from 1970 to 2004 that contain the keywords "clozapine and myocarditis," "clozapine and cardiomyopathy," "clozapine and cardiotoxicity," "clozapine and sudden death" or "clozapine and mortality." We also manually searched the bibliographies of these articles for related sources.

STUDY SELECTION

We reviewed the 30 case reports, case series, laboratory and clinical trials, data mining studies, and previous reviews identified by this search.

DATA SYNTHESIS

Recent evidence suggests that clozapine is associated with a low (0.015% to 0.188%) risk of potentially fatal myocarditis or cardiomyopathy. The drug is not known to be independently associated with pathologic prolongation of the QTc interval, but it may contribute to pathologic QTc prolongation in patients with other risk factors for this condition.

CONCLUSIONS

The low risk of a serious adverse cardiac event should be outweighed by a reduction in suicide risk for most patients taking clozapine. We provide recommendations for assessing and monitoring cardiac status in patients prior to and after initiation of treatment with clozapine.

Psychotropic drugs, cardiac arrhythmia, and sudden death

A variety of drugs targeted towards the central nervous system are associated with cardiac side effects, some of which are linked with reports of arrhythmia and sudden death. Some psychotropic drugs, particularly tricyclic antidepressants (TCAs) and antipsychotic agents, are correlated with iatrogenic prolongation of the QT interval of the electrocardiogram (ECG). In turn, this is associated with the arrhythmia (TdP). This review discusses the association between psychotropic agents, arrhythmia and sudden death and, focusing on TCAs and antipsychotics, considers their range of cellular actions on the heart; potentially pro-arrhythmic interactions between psychotropic and other medications are also considered. At the cellular level TCAs, such as imipramine and amitriptyline, and antipsychotics, such as thioridazine, are associated with inhibition of potassium channels encoded by In many cases this cellular action correlates with ECG changes and a risk of TdP. However, not all psychotropic agents that inhibit HERG at the cellular level are associated equally with QT prolongation in patients, and the potential for QT prolongation is not always equally correlated with TdP. Differences in risk between classes of psychotropic drugs, and between individual drugs within a class, may result from additional cellular effects of particular agents, which may influence the consequent effects of inhibition of repolarizing potassium current.

Antipsychotics and QT prolongation

OBJECTIVE

To evaluate literature relating to cardiac QT prolongation and the use of antipsychotic drugs.

METHOD

Literature searches of EMBASE, Medline, PsychLIT were performed in December 2001 and reference sections of retrieved papers scrutinized for further relevant reports.

RESULTS

The Cardiac QTc interval is difficult to measure precisely or accurately but appears to be a useful predictor of risk of dysrhythmia (specifically torsade de pointes) and sudden death. It is less clear that drug-induced QTc prolongation gives rise to similar risks but data are emerging, linking antipsychotic use to increased cardiac mortality. Many antipsychotics have been clearly associated with QTc prolongation. Methodological considerations arguably preclude assuming that any antipsychotic is free of the risk of QTc prolongation and dysrhythmia.

CONCLUSION

Available data do not allow assessment of relative or absolute risk of dysrhythmia or sudden death engendered by antipsychotics but caution is advised. Risk of dysrhythmia can very probably be reduced by careful prescribing of antipsychotics in low doses in simple drug regimens which avoid metabolic interactions. Electrocardiographic monitoring may also help to reduce risk but review by specialist cardiologist may be necessary.

Antipsychotics and sudden death: is thioridazine the only bad actor?

For at least the past 30 years it has been known that people with schizophrenia have higher death rates, particularly from cardiovascular causes, than would be expected on the basis of demographics (Allebeck &amp; Wistedt, 1986; Mortensen &amp; Juel, 1990; Newman &amp; Bland, 1991; Walker et al, 1997). Initially, suspicion focused upon lifestyle factors, such as ubiquitous smoking and poor self-care, and perhaps upon a direct effect of the disease. However, some of the suspicion began to shift to the drugs used to treat the disease, fuelled both by the accumulation of case reports among antipsychotic users of serious ventricular arrhythmias and sudden unexpected deaths (Liberatore &amp; Robinson, 1984; Kriwisky et al, 1990; Mehtonen et al, 1991; Donatini et al, 1992; Thomas, 1994; Jackson et al, 1997; Ravin &amp; Levenson, 1997; Zarate et al, 1997; Dickinson, 2000), as well as advancing understanding of the electrophysiological properties of these drugs (Thomas, 1994; Suessbrich et al, 1997; Drici et al, 1998; Rampe et al, 1998; Shader &amp; Greenblatt, 1998; Studenik et al, 1998; Reilly et al, 2000).