Cardiovascular system, elderly

T. Kimura, T. Kanda, A. Kuwabara, H. Shinohara, I. Kobayashi, Participation of the pituitary-thyroid axis in the cardiovascular systemic elderly patients with congestive heart failure, J Med 28, 75-80 (1997). 

There is a high degree of variation in response among individuals in a tyijical population. Generally, sensitive populations include the elderly, children, and individuals with diseases that compromise the respiratory or cardiovascular system. 

One claimed advantage of exercise in the elderly is to maintain an effective cardiovascular system so that a mild trauma or infection does not overload the system and the brain receives its required supply of oxygen and fuel under such conditions i.e. physical fitness allows the elderly person to respond adequately to a mild stress not... 

Adolescent and elderly patients - Initially, 5 mg 3 times/day increase gradually, if necessary. In elderly patients, monitor the cardiovascular system closely if dose exceeds 20 mg/day. 

The adverse effects of most serious concern relate to the cardiovascular system and seizure threshold. Actions on the adrenergic and cholinergic systems probably contribute to both hypotensive and direct cardiac effects, including alterations in heart rate, quinidine-like delays in conduction, and reduced myocardial contractility. The seizure threshold is lowered, increasing the frequency of epileptic seizures. All of these adverse effects can occur at therapeutic dosages in susceptible populations, such as elderly people, children, and people with cardiac problems or epilepsy, but are also a major cause of morbidity and mortality in accidental or intentional overdosage. Doses in excess of 500 mg can be seriously toxic, and death is fairly common when doses of 2 g or more are taken. 

Cardiovascular system. Atropine reduces vagal tone thus increasing the heart rate, and enhancing conduction in the bundle of His, effects that are less marked in the elderly in whom vagal tone is low. Full atropinisation may increase rate by 30 beats/min in the young, but has little effect in the old. 

Monoamine oxidases (both MAO-A and MAO-B) also exist in peripheral tissue, specifically the gastrointestinal tract (GIT). In the GIT, they inhibit the first-pass metabolism of exogenous tyramine. Because of this property, treatment with non-selective irreversible MAOIs can result in the accumulation of tyramine and have the potential to precipitate a dangerous hypertensive crisis, the so-called cheese effect. This effect may occur more frequently in elderly than in younger patients, because the cardiovascular systems of the elderly are already compromised by age. Selective MAO-B inhibitors and reversible MAO-A inhibitors are free from this potentially fatal interaction. 

The nonsalicylate NSAIDs can also affect renal function. Risk factors fc>r NSAID-induced acute renal failure include congestive heart feilure, glomerulonephritis, chronic renal insufficiency, cirrhosis, systemic lupus erythematosus, diabetes mellitus, significant atherosclerotic disease in the elderly and use of diuretics. NSAIDs can adversely affect cardiovascular homeostasis and can be a risk factor for the onset or exacerbation of heart feilure. 

The respiratory and cardiovascular adverse effects of topical therapy with timolol or betaxolol have been studied in a randomized, controlled trial in 40 elderly patients with glaucoma (83). Five of the 20 allocated to timolol discontinued treatment for respiratory reasons, compared with three of the 20 patients allocated to betaxolol There were no significant differences in mean values of spirometry, pulse, or blood pressure between the groups. This study confirms that beta-blockers administered as eye-drops can reach the systemic circulation and that serious adverse respiratory events can occur in elderly people, even if they are screened before treatment for cardiac and respiratory disease. These events can occur using either the selective betaxolol agent or the non-selective timolol. 

Blockade of the cardiac H-2 receptors is the postulated mechanism for the cardiovascular toxicity associated with cimetidine overdosage. Cimetidine penetrates the blood-brain barrier and is associated with central nervous system effects in predisposed individuals, including elderly, and patients with poor renal function. 

Persons at greatest risk for NSAID hemodynamic nephropathy generally have pre-existing renal insufficiency, medical problems associated with high plasma renin activity (hepatic disease with ascites, decompensated congestive heart failure, or intravascular volume depletion), or systemic lupus erythematosus. Additional risk factors include atherosclerotic cardiovascular disease and diuretic therapy. The elderly are also at higher risk due to interaction of prevalent medical problems, multiple drug therapies, and reduced renal hemodynamics. Advanced age, however, has not been shown to be an independent risk factor for toxicity in limited trials in otherwise healthy elderly subjects. Combined NSAID and ACEl or ARB therapy is also a concern and should be avoided. 

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