& u nary venous congestion under basal conditions. ''Loop'' diuretics, usually furo-semide, are most effective in patients with CHF. Furosemide has several attractive features for CHF patients: potency, including the fact that increasing doses usually cause incremental diuretic effects, low toxicity, and low cost. As with all diuretics, especially in diabetic patients who may have nephropathy, care must be taken to avoid prerenal azotemia. Thiazide diuretics should generally be avoided in diabetic patients with CHF because of adverse effects on blood glucose. In patients with severe or refractory volume overload, especially when the systemic venous pressure is particularly high, it may be useful to add a second diuretic agent. Metalozone and spironolactone are often effective. As discussed below, spironolactone improves survival and clinical class in patients with CHF and a low ejection fraction in doses that are thought to be too low to have a significant diuretic effect. When used for the specific purpose of stimulating diuresis, however, spironolactone should be used in ''diuretic'' doses, typically 25 mg p.o. three times daily. Supplemental potassium should ordinarily be discontinued when initiating spironolactone therapy and serum potassium should be monitored. Many diabetic patients manifest modest hyporeninemia and hypoka-lemia. Thus, use of diuretics and potassium supplementation requires careful attention to potential changes in electrolytes over time.

Digitalis. After many years of controversy, the role of digitalis glycosides as a component of the modern therapy of CHF has been resolved with the recent publication of a large, randomized trial. These data show that routine administration of digitalis reduces long-term morbidity, reflected in a reduced hospital readmission rate, but does not alter long-term survival. Thus, there is objective justification for administration of digitalis. When administered with careful attention to dose selection in relation to age and renal function, digoxin can be used with very low toxicity. The higher incidence of renal insufficiency in diabetic subjects should of course engender extra caution in regard to dose selection as well as judicious monitoring of serum digoxin levels.

It is likely that digitalis is effective in CHF because of resensitization of blunted baroreceptor responses with attendant deactivation of the sympathetic nervous system rather than because of its effects on cardiac contractility, which are actually very modest. It is not known whether this effect is altered in diabetic subjects with autonomic neuropathy.


Angiotensin-Converting-Enzyme Inhibitors. In chronic CHF neurohu- |

moral activation, including the renin-angiotensin-aldosterone and sympathetic nervous systems, has long-term adverse effects. Several large, controlled clinical trials have firmly established angiotensin-converting-enzyme (ACE) inhibitors as one of the cornerstones of the modern pharmacological therapy of low-ejection-fraction myocardial failure, both ischemic and nonischemic in etiology. The tis- J

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