A mechanism of sudden death in chlorpromazine therapy

A Summary of Current Information, Mechanisms and Treatment

Adverse reactions and the possible mechanisms of the reactions caused by antipsychotics are reviewed. The mechanisms of many of these adverse reactions have not been elucidated to date, hence there have been inconsistent approaches to the problem. Complicated symptoms of the reactions, especially exacerbation of the mental state, are often considered to be a part of the psychosis under treatment. Some of the reactions are temporary, or the patient may develop tolerance to them so that an additional drug may not be necessary.

It is suggested that use of the minimum dosage of antipsychotics, avoidance of polypharmacy, and close observation of the patient constitute the best approach to the prevention of unwanted reactions.

Managing cardiovascular disease risk in patients treated with antipsychotics: a multidisciplinary approach

Background

The use of antipsychotic medication in the United States and throughout the world has greatly increased over the last fifteen years. These drugs have significant side effect burdens, many of them relating to cardiovascular health.

Objective

To review the available evidence on the major cardiovascular issues that arise in patients taking antipsychotic medication.

Method

A PubMed literature review was performed to identify recent meta-analyses, review articles, and large studies. Further articles were identified through cited papers and based on expert consultation when necessary.

Results

Clinical guidance on the following adverse effects and antipsychotics was reviewed: electrocardiogram (ECG) changes, (specifically, prolonged QT and risk of torsades de pointes), weight gain, dyslipidemia, metabolic syndrome, and myocarditis. Specific attention was paid to monitoring guidelines and treatment options in the event of adverse events, including dose change, medication switch, or adjuvant therapy.

Antipsychotic-related QTc prolongation, torsade de pointes and sudden death

Sudden unexpected deaths have been reported with antipsychotic use since the early 1960s. In some cases the antipsychotic may be unrelated to death, but in others it appears to be a causal factor. Antipsychotics can cause sudden death by several mechanisms, but particular interest has centred on torsade de pointes (TdP), a polymorphic ventricular arrhythmia that can progress to ventricular fibrillation and sudden death. The QTc interval is a heart rate-corrected value that represents the time between the onset of electrical depolarisation of the ventricles and the end of repolarisation. Prolongation of the QTc interval is a surrogate marker for the ability of a drug to cause TdP. In individual patients an absolute QTc interval of >500 msec or an increase of 60 msec from baseline is regarded as indicating an increased risk of TdP. However, TdP can occur with lower QTc values or changes. Concern about a relationship between QTc prolongation, TdP and sudden death applies to a wide range of drugs and has led to the withdrawal or restricted labelling of several. Among antipsychotics available in the UK, sertindole was voluntarily suspended, droperidol was withdrawn, and restricted labelling introduced for thioridazine and pimozide. The degree of QTc prolongation is dose dependent and varies between antipsychotics reflecting their different capacity to block cardiac ion channels. Significant prolongation is not a class effect. Among currently available agents, thioridazine and ziprasidone are associated with the greatest QTc prolongation. Virtually all drugs known to cause TdP block the rapidly activating component of the delayed rectifier potassium current (I(kr)). Arrhythmias are more likely to occur if drug-induced QTc prolongation coexists with other risk factors, such as individual susceptibility, presence of congenital long QT syndromes, heart failure, bradycardia, electrolyte imbalance, overdose of a QTc prolonging drug, female sex, restraint, old age, hepatic or renal impairment, and slow metaboliser status. Pharmacodynamic and pharmacokinetic interactions can also increase the risk of arrhythmias. Further research is needed to quantify the risk of sudden death with antipsychotics. The risk should be viewed in the context of the overall risks and benefits of antipsychotic treatment. It seems prudent, where possible, to select antipsychotics that are not associated with marked QTc prolongation. If use of a QTc-prolonging drug is warranted, then measures to reduce the risk should be adopted.

On the early recognition of neuroleptic malignant syndrome

Neuroleptic Malignant Syndrome, a serious and sometimes fatal complication, has been reported to occur in some patients with the administration of neuroleptic medications. Clinically it is manifested by four groups of symptoms which include muscular hypertonicity, autonomic instability, altered consciousness, and hyperthermia. Laboratory findings such as elevated creatinine phosphokinase and leukocytosis are also seen. While it is true that the incidence of the full blown clinical picture of this syndrome is rare, the authors report that only muscular hypertonicity and autonomic instability have occurred frequently in their setting leading to discontinuation of neuroleptics. Such abortive cases may go undetected. If properly diagnosed, the occurrence of this syndrome is not as rare as the published reports indicate. Second, it is reported that rechallenge with neuroleptics may not induce Neuroleptic Malignant Syndrome again. The authors noted recurrence of fever after rechallenge with a different neuroleptic drug. This article describes the method of early recognition and prevention of morbidity as well as mortality.

Management of intractable hiccup

A patient who developed hiccups after laparotomy was treated with numerous drugs with limited success. A left phrenic nerve crush was eventually successful. A review of published work showed that the drugs most likely to succeed were chlorpromazine and metoclopramide, and that phrenic nerve injection and crush should be considered if these failed.

Biologic and psychosocial risk factors of sudden death from coronary disease in white women

The relation of the risk of sudden death from arteriosclerotic heart disease to psychosocial and biologic factors was studied retrospectively in 64 white women who died suddenly of arteriosclerotic heart disease and in 64 age-related neighborhood control women. All sudden deaths occurred outside the hospital within 24 hours of the onset of symptoms in women who were not incapacitated before death. Women who died suddenly were less often married, exhibited more educational incongruity with their spouses and had fewer children than the control population. Twelve of the 64 women who died suddenly of heart disease and none of the control women had a definite history of psychiatric treatment. The women who died suddenly also smoked more cigarette and consumed greater quantities of alcoholic beverages than age-matched neighborhood control women. Multiple regression analysis revealed that history of psychiatric illness, cigarette smoking, alcohol consumption, educational incongruity and number of children contributed significantly to differences between women who died suddenly of heart disease and control subjects.

Psychopharmacologic management of anxiety in the cardiac patient

Of 253 patients who had suffered acute myocardial infarction ( MI), 88 percent received daytime sedation while hospitalized. Sixty percent of all prescriptions were for phenobarbital, 30 percent for chlordiazepoxide, and 6 percent for meprobamate. In addition, 79 percent of patients received night time hypnotic medication. Sixty-six percent of such prescriptions were for short-acting barbiturates, 21 percent for chloral hydrate, and 7 percent for diphenhydramine. Multiple drug use was common.

The barbiturates, while inexpensive sedative agents, are of questionable efficacy in reducing anxiety and probably produce only general CNS depression. A narrow margin of safety, liability to produce habituation, and antagonism of warfarin-type anticoagulants are other disadvantages. The benzodiazepine tranquilizers, whose antianxiety efficacy is more clearly established, do not produce general CNS depression, have a wide margin of safety, and do not interact with oral anticoagulants.

Antidepressant agents, phenothiazine tranquilizers, and propranolol were used infrequently or not at all. The risks associated with the use of these agents in patients with acute myocardial infarction are considerable and should be weighed carefully before they are administered.