Hyponatraemia in congestive heart failure during treatment with captopril

Sodium and Potassium Disturbances in the Elderly

OBJECTIVE

To study the incidence of sodium and potassium disturbances in a population of the very old elderly, with respect to medication with potential effects on electrolyte levels.

DESIGN AND SETTING

Cross-sectional study of subjects aged >/=75 years, based on data from the Kungsholmen project, a population-based study of elderly in an urban area of Stockholm, Sweden.

STUDY PARTICIPANTS

1558 elderly individuals (1178 women and 380 men), mean age 81.4 years, providing information about drug use and serum electrolyte data.

MAIN OUTCOME MEASURES

Data on drug use was based on personal interviews. Hyponatraemia was defined as a serum sodium concentration <136 mmol/L, hypernatraemia as a serum sodium concentration >146 mmol/L, hypokalaemia as a serum potassium concentration <3.5 mmol/L and hyperkalaemia as a serum potassium concentration >5.0 mmol/L.

RESULTS

Hyponatraemia was found in 147 subjects (9.4% of the study population) and hypernatraemia in five individuals (0.3%). Hypokalaemia was found in 39 (2.5%) and hyperkalaemia in 43 (2.8%) of the subjects. The prevalence of hyponatraemia (p < 0.001), hypokalaemia (p < 0.05) and hyperkalaemia (p < 0.05) increased with age. Hyponatraemia was found more often in women than in men (p < 0.05). Hypernatraemia was more frequent in subjects who lived in institutions (p < 0.001). The occurrence of hyponatraemia was associated with the use of carbamazepine, laxatives (enema), diuretics and ACE-inhibitors; hypernatraemia was associated with osmotically active laxatives. Hypokalaemia was associated with thiazide-related and combination diuretics; and hyperkalaemia was associated with potassium-sparing diuretics, beta-blockers, cytostatic drugs and tricyclic antidepressants.

CONCLUSIONS

The present study demonstrated the association between electrolyte level disturbances and several types of drugs in a population of the very old elderly. Our results underline the importance of monitoring serum electrolyte levels in the elderly, not only in relation to the use of diuretics, but also several other drugs.

Syndrome of inappropriate antidiuretic hormone secretion associated with lisinopril

OBJECTIVE

To describe a case of the syndrome of inappropriate antidiuretic hormone secretion (SIADH) associated with lisinopril therapy.

CASE SUMMARY

A 76-year-old white woman who was being treated with lisinopril and metoprolol for hypertension presented with headaches accompanied by nausea and a tingling sensation in her arms. Her serum sodium was 109 mEq/L, with a serum osmolality of 225 mOsm/kg, urine osmolality of 414 mOsm/kg, and spot urine sodium of 122 mEq/L. Diclofenac 75 mg qd for osteoarthritic pain and lisinopril 10 mg qd for hypertension was begun in 1990. Lisinopril was increased to 20 mg qd in August 1994 and to 20 mg bid pm in August 1996 for increasing blood pressure; metoprolol 50 mg qd was added in July 1996. A diagnosis of SIADH was postulated and further evaluation was undertaken to exclude thyroid and adrenal causes. After lisinopril was discontinued and the patient restricted to 1000 mL/d of fluid, serum sodium gradually corrected to 143 mEq/L. The patient was discharged taking metoprolol alone for her hypertension; serum sodium has remained > or =138 mEq/L through April 1999, 32 months after discharge, despite daily use of diclofenac.

DISCUSSION

Angiotensin-converting enzyme (ACE) inhibitors in antihypertensive doses may block conversion of angiotensin I to angiotensin II in the peripheral circulation, but not in the brain. Increased circulating angiotensin I enters the brain and is converted to angiotensin II, which may stimulate thirst and release of antidiuretic hormone from the hypothalamus, eventually leading to hyponatremia.

CONCLUSIONS

SIADH should be considered a rare, but possible, complication of therapy with lisinopril and other ACE inhibitors.

Incidence and risk factors for hyponatraemia following treatment with fluoxetine or paroxetine in elderly people

AIMS

To establish the incidence, time course and risk factors of hyponatraemia complicating treatment with fluoxetine or paroxetine in an elderly population.

METHODS

Retrospective descriptive and case control study in an inpatient/outpatient assessment and rehabilitation service for people aged 65 years and over. Fourteen elderly patients with hyponatraemia complicating treatment with fluoxetine or paroxetine, matched with 56 controls drawn from 845 patients treated with fluoxetine or paroxetine over 3.5 years. No other SSRI antidepressants were used over the study period.

RESULTS

The incidence of hyponatraemia was 4.7/1000 people treated/year (6.3/1000 for fluoxetine and 3.5/1000 for paroxetine). Hyponatraemia was detected at a median 13.5 (mean 18.6, range 4-64) days after commencing the drug. Mean (95% confidence intervals) body weights were lower in cases at 53.0 (95% CI 46.5-59.5) kg compared with controls at 64.5 (95% CI 60.1-68.4) kg (P<0.01). 71% of cases were women compared with 45% of controls (P=0.07) but the effect of gender was confounded by body weight. There were trends for cases to be older (odds ratio 1.10: 95% CI 0.99, 1.23) and lighter (odds ratio 0.92, 95% CI 0.86, 0.99).

CONCLUSIONS

Approximately 1 in 200 elderly people treated per year with fluoxetine or paroxetine developed complicating hyponatraemia. Low body weight was a particular risk factor. Most cases occurred within 3 weeks of treatment.

Severe thiazide-induced hyponatraemia during treatment with enalapril

A patient is described who developed mild hyponatraemia on two occasions when treated with bendrofluazide alone, but severe hyponatraemia when treated with the combination of enalapril and bendrofluazide.

Acute hemodynamic, hormonal and electrolyte effects of ramipril in severe congestive heart failure

The response to ramipril, 10 and 20 mg on consecutive days, in 9 patients with severe (New York Heart Association functional class III or IV) chronic congestive heart failure was measured. Hemodynamic cannulae were placed more than 2 days before ramipril administration to ensure a stable baseline. Dietary sodium (40 mmol daily) and potassium (80 mmol daily) were constant before and during the study, and maintenance doses of digoxin and furosemide (80 to 1,000 mg daily) were continued unchanged. Ramipril induced pronounced, sustained decreases in angiotensin converting enzyme activity, angiotensin II and aldosterone levels, and a reciprocal increase in plasma renin activity. Plasma catecholamines, antidiuretic hormone and cortisol levels were not altered. Urinary sodium and potassium excretion diminished, plasma sodium decreased and plasma potassium increased. Plasma urea and creatinine levels increased. Ramipril treatment resulted in a decrease in systemic arterial pressure that was sustained for 24 hours, a decrease in heart rate and an increase in cardiac index, but little change in pulmonary artery pressure or right atrial pressure. Three patients were drowsy after ramipril administration, and 1 patient had a marked, temporary reduction in urine output. It was concluded that ramipril is a potent, long-acting angiotensin converting-enzyme inhibitor that is likely to be beneficial in patients with severe cardiac failure.

Adverse reactions with angiotensin converting enzyme (ACE) inhibitors

Teprotide, a nonapeptide isolated from the venom of a Brazilian pit viper, Bothrops jararaca, was the first angiotensin converting enzyme (ACE) inhibitor to be discovered and tested. It was found to be an effective, non-toxic antihypertensive agent as well as an afterload-reducing agent for patients with congestive heart failure (CHF). The primary activity of teprotide resulted from blockade of the angiotensin I converting enzyme--the pivotal step in the renin-angiotensin-aldosterone system (RAAS), and consequent reductions in angiotensin II levels. There was limited clinical testing for teprotide because of: its scarcity; the need for parenteral administration; and the subsequent discovery and synthesis of captopril, the first orally active angiotensin converting enzyme inhibitor. Captopril is the prototype oral angiotensin converting enzyme inhibitor and has been extensively studied since the initiation of formal studies in 1976. Perhaps one of the most closely researched drugs in modern times, the experience with captopril now includes more than 12,000 patients studied in formalized trials and over 4,000,000 patients treated world-wide by physicians for hypertension and congestive heart failure. Enalapril (MK421) is the first of what appears to be a growing number of analogues which are structurally and pharmacodynamically different from captopril; yet, they possess the same capacity for inhibiting the activity of angiotensin converting enzyme. The side effect profile of enalapril (and presumably future) angiotensin converting enzyme inhibitors appears to be similar to captopril, though clearly more experience is needed with newer agents. The initial use of captopril was troubled by a relatively high incidence of side effects which will form the focus of this discussion. Partially the result of incomplete pharmacokinetic information, captopril was administered in early studies at dosages now recognised to be far in excess of those necessary for drug action. In addition, dosages were given without regard for deficiencies of renal function, now known to be the main excretory route of captopril. The population of those patients studied frequently had chronic, treatment-resistant hypertension, often associated with concomitant end-organ disease (especially renal disease); and many additional factors further complicating the clinical setting, e.g. a relatively high incidence of collagen vascular disease and immunosuppressive treatments.(ABSTRACT TRUNCATED AT 400 WORDS)

Captopril-induced hyponatremia with irreversible neurologic damage

A 61-year-old Chinese-American man with a history of congestive heart failure and hypertension was admitted to the San Francisco Veterans Administration Hospital with confusion, cortical blindness, and generalized flaccidity. Serum sodium level on admission was 114 meq/liter. Administration of captopril had been begun for afterload reduction two weeks before admission with a concomitant fall in serum sodium level from 137 meq/liter to 126 meq/liter in one week. A history of marked thirst with consumption of large volumes of water was reported for over one week prior to hospitalization. Despite correction of the hyponatremia within 24 hours at a rate of 0.9 meq/liter per hour, the patient remained semi-comatose and died four days later with a gastrointestinal bleed. It is suggested that the thirst phenomenon and hyponatremia were caused by the introduction of captopril. This lead to irreversible neurologic damage and death, despite the correction of the serum sodium level.

Relation between serum sodium concentration and the hemodynamic and clinical responses to converting enzyme inhibition with captopril in severe heart failure

The relation between pretreatment serum sodium concentration and the early and late effects of captopril was examined in 77 consecutive patients with severe chronic heart failure, in whom cardiac catheterization was performed during initiation of treatment and after 2 to 8 weeks. Two groups of patients were defined: 37 patients had hyponatremia (serum sodium less than 135 mEq/liter, group A) and 40 patients had a normal serum sodium concentration (greater than or equal to 135 mEq/liter, group B). With first doses of captopril, patients in group A showed more marked hemodynamic responses than did patients in group B (p less than 0.02). The changes in mean arterial pressure and left ventricular filling pressure seen with first doses of the drug varied linearly and inversely with the pretreatment serum sodium concentration (r = -0.58 and r = -0.53, respectively); this was likely related to the finding that, before administration of captopril, the serum sodium concentration varied linearly and inversely with the logarithm of the plasma renin activity (r = -0.78). However, the pretreatment serum sodium concentration did not predict the long-term hemodynamic or clinical responses to converting enzyme inhibition. Symptomatic hypotension occurred early in the course of therapy (within 24 hours of initiating captopril therapy) in 9 (12%) of the 77 patients; 8 of these 9 had severe hyponatremia (serum sodium less than 130 mEq/liter) and comprised 53% of the 15 patients in our study with such low serum sodium concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug-induced electrolyte disorders

A wide variety of pharmacologic agents have been implicated in a number of electrolyte disorders. The present review focuses on abnormalities of sodium, potassium, calcium, magnesium, and phosphate. Several mechanisms are involved in the pathogenesis of these disorders. These involve stimulation and modulation of other hormones (e.g., antidiuretic hormone, renin-angiotensin system, parathyroid hormone), damage to renal tubules, and, in some cases, a combination of factors. Recognition of these abnormalities is important because their presence may be life threatening or may aggravate the side effects of the drug itself.

Captopril: an update review of its pharmacological properties and therapeutic efficacy in congestive heart failure

Captopril is the first angiotensin-converting enzyme inhibitor for oral administration. In combination with continued digitalis and diuretic therapy it has been demonstrated to be effective in the management of severe heart failure refractory to optimal digitalis, diuretic and, in many patients, vasodilator treatment. Most studies to date have been open trials of several weeks or months duration, but a number of patients have received continued treatment, with sustained benefit, for up to 1 year or more. A placebo-controlled trial in a limited number of patients with less severe heart failure has confirmed the results of open trials. Captopril administration improves cardiac performance as a result of a reduction in systemic vascular resistance (afterload) and the various determinants of left ventricular filling pressure (preload). Improvements in exercise tolerance and functional classification, with associated reduction of clinical symptomatology, occur with simultaneous decreases in myocardial oxygen consumption. At present, captopril is worthy of a trial in patients refractory to more traditional medical management. Whether it should be considered a 'first-line' agent after failure of optimal digitalis and diuretic therapy, and before instituting other vasodilator therapy, is less clear. In patients with severe or resistant heart failure, a response to captopril is usually accompanied by a general improvement in the quality of life. The effect of captopril treatment on 1- and 2-year survival rates in patients with severe heart failure appears similar to that reported for other vasodilators. Most patients tolerate captopril treatment well, but hypotension, reduced renal function, skin rash, dysgeusia, and neutropenia have been reported.

[Captopril in congestive heart failure (author's transl)]

Captopril (Lopirin, Squibb, von Heyden) is an inhibitor of the angiotensin-I converting enzyme. In congestive heart failure angiotensin mediated vasoconstriction and aldosterone secretion is reversed by captopril. Both effects of captopril induce reduction of cardiac preload and afterload. The clinical state of patients with congestive heart failure therefore improves since cardiac output increased and pulmonary pressures decrease. Captopril acts orally and the dosage used for the treatment of congestive heart failure ranges from 50 to 150 mg daily. After oral ingestion of a single dose the maximum haemodynamic effect is observed after 45-90 min. No tolerance induction or tachyphylaxis has been observed during maintenance therapy over a period of 18 months. There are some reversible adverse reactions like pruritus, skin rash and partial or complete taste loss which are dose related. Serious side effects include leucopenia, agranulocytosis, renal failure and membranous glomerulonephritis. Therefore regular urinary and blood analysis is necessary during captopril therapy.

Captopril: a preliminary review of its pharmacological properties and therapeutic efficacy

Captopril is the first orally active inhibitor of angiotensin-converting enzyme to become available. It has been studied primarily in hypertension. In mild to moderate essential hypertension captopril is about as effective as usual doses of hydrochlorothiazide or propranolol, about one-half of such patients needing the addition of a diuretic to achieve satisfactory control of blood pressure. In severe hypertension captopril plus a diuretic (and in some patients a beta-blocker) usually reduced blood pressure significantly more than could be achieved with 'standard triple therapy' in patients not responding adequately to such a regimen, and often resulted in an improved feeling of well-being in severely hypertensive patients previously receiving intensive multiple drug therapy. Indeed, at the present stage of the drug's development, patients not responding to or not tolerating 'traditional' antihypertensive therapy represent the most suitable candidates for captopril treatment. While captopril has been well tolerated in most patients, some troublesome or potentially serious side effects have been reported, including agranulocytosis, dysgeusia and reduced renal function; although a clear causal relationship with captopril was not always established, it would appear that the final place of captopril in the treatment of hypertension may ultimately depend on further clarification of its adverse effects profile. In addition to studies in hypertension, captopril has produced encouraging improvement in a small number of patients with severe congestive heart failure resistant to conventional therapy. Captopril must be considered an exciting addition to the therapeutic armamentarium; it, and pharmacologically related compounds of the future, will continue to generate much interest as their final place in therapy becomes better defined through additional well designed studies and wider clinical experience.