Studies on the bronchodilator, tremorogenic, cardiovascular and hypokalaemic effects of fenoterol dry powder in asthma.
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1. The airway and tremor response and cardiovascular and hypokalaemic effects of single and cumulative doses of fenoterol given by dry powder capsules (DPC) and by metered dose inhaler (MDI) were studied in asthmatics in two randomized, crossover trials. 2. Single doses of fenoterol DPC and MDI (0.2 mg, 0.4 mg), investigated in 24 subjects, produced similar, dose-dependent increases in FEV1. Fenoterol DPC caused less tremor response and less hypokalaemic effects than fenoterol MDI. 3. Cumulative doses of fenoterol DPC and MDI (0.2, 0.6, 1.4, 3.0, 6.2 mg), investigated in 12 subjects, produced a comparable bronchodilatation (mean maximum increase in FEV1 was 0.53 +/- 0.06/0.52 +/- 0.081 for DPC/MDI) and a similar, dose-dependent rise in heart rate (35 +/- 3.81/41 +/- 2.25 beats min(-1)). The rise in tremor and the fall in plasma potassium were smaller after DPC than after MDI. The mean maximum changes were 51.58 +/- 6.41/95.83 +/- 6.75 cm s(-2) for tremor and -0.68 +/- 0.09/-0.96 +/- 0.10 mmol l(-1) for potassium. 4. Our findings may result from a difference in the pharmacokinetics of the dry powder and the aerosol formulation, particularly differences in distribution and absorption. 5. In conclusion, fenoterol DPC used in low therapeutic doses (0.2,0.4 mg), is preferable to the MDI. Fenoterol DPC used as rescue medication in high cumulative doses, do not suggest a greater safety margin than the MDI and the same restrictions should be considered for the fenoterol dry powder formulation as suggested for the MDI. (+info)
Renal potassium wasting in distal renal tubular acidosis: role of aldosterone.
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The pathogenesis of renal potassium wasting and hypokalemia in classic renal tubular acidosis (type 1 RTA) remains uncertain. The prevailing theory is that K(+)-Na+ exchange is stimulated due to an inability of the distal tubule to establish a normal steep lumen-peritubular H+ gradient. We encountered a 42-year-old woman with type 1 RTA associated with Sjogren's syndrome, in whom renal potassium wasting and hypokalemia persisted despite sustained correction of systemic acidosis with alkali therapy and increased intake of potassium. In addition, plasma renin activity was markedly increased and the serum aldosterone level was upper-normal despite the hypokalemia. Increased intake of sodium resulted in suppression on the serum aldosterone and correction of renal potassium wasting and hypokalemia. This case shows that secondary hyperaldosteronism, possibly due to an impairment of sodium conservation in the distal tubule, may contribute to the loss of potassium from the distal tubule even after the correction of acidosis. (+info)
The toxic effects of amphotericin B in man.
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Studies of 47 patients with intravenous amphotericin B revealed some impairment of renal function in all cases. Azotemia developed in 46 cases. Microscopic examination in eight cases showed damage to the distal renal tubule. Profound hypokalemia was recognized in two cases; and symptoms suggesting hypokalemia, which were generally ameliorated by potassium administration, were noted in most cases. It is postulated that the initial potassium loss is due to a "tubular leak" and that subsequent potassium depletion leads to further tubular damage. Mild to severe anemia developed in all cases during therapy. Serial red cell indices, bone marrow examinations and red cell survival studies indicated that hemolysis, rather than bone marrow depression, was responsible.The decision to treat, to modify therapy or to terminate treatment must be made on the basis of severity of disease, probability of progression, and renal status. (+info)
TOXIC MEGACOLON IN ULCERATIVE COLITIS.
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Toxic dilatation of the colon is now a well-recognized complication of ulcerative colitis. Our experience with four cases is presented. The clinical picture was characterized by severe ulcerative colitis with increasing abdominal distension, high swinging temperatures, obvious toxicity, and a moderate to high leukocytosis with a pronounced shift to younger forms. Accurate history and physical examination, plain radiographs of the abdomen, sigmoidoscopy and, most important of all, awareness of the condition facilitate diagnosis in most cases. The main indications for surgical intervention are progressive abdominal distension and impending or actual perforation. Ileostomy and subtotal or total colectomy are the surgical procedures of choice. We feel that steroids play little part in the early management, but are of value in the early postoperative period. The three patients in our series treated surgically survived. One treated by medical means alone died of peritonitis. (+info)
CLINICAL EXPERIENCE WITH A NEW DIURETIC, TRIAMTERENE, IN CONJESTIVE HEART FAILURE.
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Triamterene therapy was evaluated in 35 patients with congestive heart failure over a period of two and one-half years. The parameters used were: clinical assessment; daily 24-hour urine sodium, potassium, chloride, and total volume; bi-weekly serum sodium, potassium, chloride, uric acid, and SGOT; hemogram, and BUN.Triamterene is a moderately potent diuretic and natriuretic, with the added desirable property of potassium conservation. It acts synergistically with spironolactone and not only potentiates the effects of hydrochlorothiazide but greatly minimizes its kaluretic effect.It is particularly useful in patients in whom cardiac arrhythmias are associated with digitalis intoxication or with inadvertently induced hypokalemia. Its main therapeutic value, used either alone or in combination with other diuretics, is in the longterm management of chronic edema, especially in certain patients refractory to the currently used diuretics.No significant undesirable side effects were noted. (+info)
CARCINOMA OF LUNG WITH ADRENAL HYPERFUNCTION AND HYPERCALCEMIA TREATED BY PARATHYROIDECTOMY.
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A case of severe hypercalcemia secondary to carcinoma of the lung is described in which hypokalemic alkalosis, renal failure and pancreatitis were also present. The relative importance of the few bone metastases found at autopsy is considered, and a probable endocrine-like effect of the tumour in the development of the hypercalcemia is postulated. Treatment of the hypercalcemia included administration of corticosteroids and disodium EDTA, peritoneal dialysis and subtotal parathyroidectomy; the most effective of these was peritoneal dialysis. Subtotal parathyroidectomy failed to produce a further decrease in serum calcium values. The occurrence of hypokalemic alkalosis in the presence of increased adrenocortical function and its relationship to the carcinoma of the lung are discussed. The possibility that this neoplasm produced two factors which caused systemic effects ordinarily associated with the function of endocrine glands must be considered. (+info)
ISLET-CELL CARCINOMA (ZOLLINGER-ELLISON SYNDROME) WITH FULMINATING ADRENOCORTICAL HYPERFUNCTION AND HYPOKALEMIA.
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The production of ACTH-like material by tumours arising in non-endocrine tissue may initiate severe adrenocortical hyperfunction. The pathogenesis and clinical and laboratory features of Cushing's syndrome associated with such tumours are characteristic. The autonomous production by the tumour of ACTH-like material cannot be suppressed by exogenous corticoids. The onset of clinical symptoms is rapid; muscle wasting, general weakness, thirst and peripheral edema predominate, and the classical signs of Cushing's syndrome may be absent. High levels of plasma 17-hydroxycorticosteroids and urinary 17-hydroxycorticosteroids and 17-ketosteroids, usually with normal levels of urinary aldosterone, commonly occur. Hypokalemic alkalosis unresponsive to replacement therapy may cause death. In the case reported herein, the intriguing possibility exists that two hormone-like substances were produced by the primary growth and its metastases: one, ACTH-like, to account for the adrenal hyperplasia and Cushing's syndrome; and another, gastrin-like, giving rise to the ulcerogenic diathesis. (+info)
A case of primary renal renin secretion of probable neoplastic origin is reported. Investigation demonstrated renin secretion to be incompletely autonomous with suboptimal suppression to posture and hypervolaemia. Easy control of the hypertension and hypokalaemia was achieved with an angiotensin converting enzyme inhibitor. Such treatment may prove to be a preferable option to surgery. (+info)