Digitalis delirium in elderly patients

Age-related modifications in CYP-dependent drug metabolism: role of stress

Accumulating clinical evidence indicates extensive inter-individual variations in the effectiveness and adverse effects of standard treatment protocols, which are largely attributed to the multifactorial regulation of the hepatic CYP-dependent drug metabolism that is connected with either transcriptional or post-translational modifications. Age and stress belong to the most important factors in CYP gene regulation. Alterations in neuroendocrine responses to stress, which are associated with modified hypothalamo-pituitary-adrenal axis function, usually accompany ageing. In this light, ageing followed by a decline of the functional integrity of organs, including liver, a failure in preserving homeostasis under stress, increased morbidity and susceptibility to stress, among others, holds a determinant role in the CYP-catalyzed drug metabolism and thus, in the outcome and toxicity of pharmacotherapy. Modifications in the drug metabolizing capacity of the liver with age have been reported and in particular, a decline in the activity of the main CYP isoforms in male senescent rats, indicating decreased metabolism and higher levels of the drug-substrates in their blood. These factors along with the restricted experience in the use of the most medicines in childhood and elderly, could explain at an extent the inter-individual variability in drug efficacy and toxicity outcomes, and underscore the necessity of designing the treatment protocols, accordingly.

Drug-induced confusional states: the usual suspects?

BACKGROUND

Acute confusional state (ACS) is a frequent reason for hospital admission. This study examines retrospectively the frequency by which individual drugs were found responsible for ACS.

RESULTS

Drug-induced ACS was found in 65 (18.8%) of 346 hospital admissions for acute confusion. The most frequent causative substances were dopaminergic drugs in Parkinsonian patients (24.2%), diuretics (15.1%), tricyclic or tetracyclic antidepressants (13.6%) and benzodiazepines (13.6%). Almost half of the patients were demented, and in one-third of these, dementia had not been diagnosed hitherto.

CONCLUSION

The data suggest that diuretics by way of causing hyponatraemia are as relevant a cause of ACS as dopaminergic or anticholinergic substances.

Age-related changes in pharmacokinetics and pharmacodynamics: basic principles and practical applications

Advancing age is characterized by impairment in the function of the many regulatory processes that provide functional integration between cells and organs. Therefore, there may be a failure to maintain homeostasis under conditions of physiological stress. The reduced homeostatic ability affects different regulatory systems in different subjects, thus explaining at least partly the increased interindividual variability occurring as people get older. Important pharmacokinetic and pharmacodynamic changes occur with advancing age. Pharmacokinetic changes include a reduction in renal and hepatic clearance and an increase in volume of distribution of lipid soluble drugs (hence prolongation of elimination half-life) whereas pharmacodynamic changes involve altered (usually increased) sensitivity to several classes of drugs such as anticoagulants, cardiovascular and psychotropic drugs. This review focuses on the main age-related physiological changes affecting different organ systems and their implications for pharmacokinetics and pharmacodynamics of drugs.

Risk factors and manifestations of digoxin toxicity in the elderly

The incidence of digoxin toxicity increases with age, largely because the two most common conditions that benefit from use of digoxin, congestive heart failure and atrial fibrillation, are markedly more prevalent in old age. Whether the elderly are more sensitive to the effects of digoxin because of age per se is unclear. However, several other factors render the elderly more susceptible to digoxin toxicity. These include an age-related decline in renal function and a decrease in volume of digoxin distribution. There is also an increase in the number of comorbid conditions, including cardiovascular and chronic obstructive pulmonary disease, which heighten susceptibility to digoxin toxicity. Moreover, treatment of these diseases with such interactive medications as quinidine and calcium channel blockers may increase the serum level of digoxin. Similarly, such electrolyte imbalances as hypokalemia and hypomagnesemia occur more frequently in the elderly as a result of diuretic therapy. However, recent data suggest that manifestations of digoxin toxicity among younger and older patients do not differ. Similar incidences of cardiac toxicity, gastrointestinal toxicity, and altered mental status are found in both patient populations. Treatment of digitalis toxicity in the elderly is the same as for younger patients. Response rates to Digibind are not diminished in the elderly.

Delirium in the elderly

Delirium is an organic psychiatric syndrome characterized by acute onset and impairment in cognition, perception, and behavior. The most common and serious mental disorder in old age, delirium heralds death in about 25% of afflicted elderly patients. Despite this high mortality rate, it is usually a transient disorder, resulting in full recovery without progressing to a chronic mental disorder. Almost any physical illness may cause delirium in an elderly person. Prompt assessment, differential diagnosis, and treatment are essential to reverse the medical disorder and control behavior that may be life threatening. This paper presents an approach to the diagnosis of delirium, reviewing descriptive features of the syndrome, biological, psychological, and environmental variables predisposing to delirium in geriatric patients, and the most common medical etiologies. It describes effective therapeutics, including ward management, supportive psychotherapy, and pharmacotherapy.

Digitalis delirium in an elderly woman

A case of anorexia, paranoid delusions, and lethargy associated with digoxin toxicity is presented here. The digitalis glycosides are among the most commonly used drugs in modern medicine, and as such, they frequently cause toxicity. Although cardiac side effects of digoxin are well recognized, less attention has been paid to potential CNS effects. Psychiatric manifestations, from calm disorientation to violent psychosis, tend to occur more often in elderly patients and may be the earliest or only sign of digitalis toxicity.

Drug-induced psychiatric disorders and their management

Psychiatric disorders induced by drugs are of most concern when they occur in the context of therapeutic use of a drug. Such iatrogenic psychiatric disturbances may interfere considerably with the treatment of the primary illness and may cause concern to patients, their relatives and the medical staff. Because many drugs are often used simultaneously in seriously ill patients, it may be difficult to be sure which drug may have been responsible. The best procedure is to remove those drugs which are most probable causes of the psychiatric disturbances as well as any drugs that are not truly essential for the treatment of the patient. Problems involved in evaluating the relationship between use of drugs and psychiatric disorders are considerable. Many reports are isolated cases and the denominators which might provide some idea of the potential risk are unknown. Many relationships are still controversial, such as the association of depression with sedatives, antihypertensives and oral contraceptives. Areas of uncertainty are great. Psychomotor impairment may be caused by a drug that can alter consciousness, or any drugs that can produce more delineated psychiatric syndromes. Sedative drugs are those most commonly associated with psychomotor impairment, and may include psychotherapeutic drugs, sedative antihistamines, narcotic analgesics and, of course, the widely used social drug, alcohol. Delirious states are most often associated with drugs that possess central anticholinergic actions. These include not only drugs clearly identified as anticholinergics, but also tricyclic antidepressants and anti-Parkinson drugs. Cimetidine, which is often used parenterally in seriously ill patients, is also a prominent cause. Delirium is most often seen in elderly patients and in those who have received rather large doses of drugs. The association of schizophrenic-like psychoses with dopaminomimetic drugs tends to support the prevailing dopamine hypothesis of schizophrenia. Levodopa, the dopamine precursor, and bromocriptine, a direct dopamine agonist, are examples of such relationships. Abuse of social drugs has also been thought to provide a useful model of schizophrenia. Hallucinogens are probably a rather poor model, abuse of amphetamines may provide a better model, and possibly the best is the psychotic state elicited by phencyclidine. Manic reactions are clinically difficult to differentiate from schizophrenic-like psychoses and are often produced by similar drugs. Corticosteroids may produce either manic or schizophrenic-like disorders, as well as occasionally confusion and depression.(ABSTRACT TRUNCATED AT 400 WORDS)

Digitalis in the elderly

Since William Withering first described the use of digitalis, over 200 years ago (1), its popularity has waxed and waned. Digitalis preparations are widely prescribed for elderly patients. Surveys of hospital in-patients have shown a high prevalence of the use of digitalis preparations (2, 3), but also of digitalis toxicity; though not all studies have shown the latter to increase with age. A survey of people aged 70, living in Gothenberg, showed that 14% were taking digitalis preparations (4); other studies have shown similar figures. Now that powerful diuretics and vasodilators are available for the treatment of heart failure, and many antiarrhythmics are used for the control of atrial tachyarrhythmias, there is controversy about the value of cardiac glycosides in the treatment of elderly patients.