Effect of captopril on heavy proteinuria in azotemic diabetics

Cyclosporine-induced remission of relapsing nephrotic syndrome in children

We treated 20 steroid-resistant or steroid-dependent nephrotic patients with oral cyclosporin for 8 weeks; they had been treated previously with cyclophosphamide or chlorambucil. Cyclosporine was started at 7 mg/kg/d and titrated to maintain a serum level of 100 to 200 ng/mL. Of 20 patients, 14 had a complete remission and the remaining six had a reduction in their proteinuria. By life table analysis, 40% of the responders show a sustained remission of up to a year. Pretherapy levels of interleukin 2, measured in 10 patients, were normal or supranormal in eight, six of whom were treatment responders; two patients with low levels of interleukin 2 were both nonresponders. Cyclosporine can be used to induce a remission in relapsing nephrotic patients, and short-term cyclosporine therapy does not produce nephrotoxic effects.

Converting enzyme inhibition and progressive glomerulosclerosis in the rat

The effect of converting enzyme inhibition (CEI) by captopril (CAP, 500 mg/liter drinking water) on the development and progression of glomerulosclerosis (GS) was studied in six groups of male uninephrectomized (UN) Wistar rats. In group A, treated with CAP for four to five weeks after UN, a reduction in systolic blood pressure (SBP), filtration fraction and glomerular volumes was found as compared to control group B. Long-term treatment with CAP for eight months after UN (group C) resulted in lowering of SBP with 30 mm Hg, a low level of proteinuria and low incidence of GS (0 to 1.5%) as compared to control rats (group D), with SBP of 131 +/- 4 mm Hg, proteinuria up to 103 to 509 mg/day and 9.1 to 29.7% GS at eight months after UN. Groups E and F were followed without therapy up to seven months after UN, at which time a high level of proteinuria was present. CAP therapy then started in group E, did not reduce SBP, proteinuria and GS at 11 months after UN relative to control group F. This study shows that early CEI prevents progressive proteinuria and GS in rats after UN and is associated with a reduction in SBP, filtration fraction and glomerular volume. Once high levels of proteinuria and GS have developed in rats after UN, CEI has no effect on SBP nor on the progression of GS and proteinuria.

Alkylating cytostatic treatment in renal amyloidosis secondary to rheumatic disease

Fourteen consecutive patients with chronic inflammatory rheumatic disease and reactive renal amyloidosis were treated with alkylating cytostatics in 22 separate periods varying in duration between six and 30 months. Chlorambucil alone was given in 14 treatment periods, cyclophosphamide alone in six, and both alternately in two. The dosage was adjusted to attain a major suppression of the rheumatic inflammation and a blood lymphocyte level below 1.0 X 10(9)/l. Renal function improved in 12 treatment periods, renal deterioration was arrested in three periods, and in another four periods the rate of functional decline slowed down. In the remaining three treatment periods, associated with further deterioration in renal function, treatment was inadequate owing to blood dyscrasia and failure to control hypertension. Glomerular filtration rate (GFR) was followed more closely in 10 treatment periods, in all of which the falling trend was arrested or reduced. The survival rate at five years was 93%. Three patients who dropped out of the treatment programme are so far the only ones not still alive. Nine are still being followed up after 6-17 years, and the other two remaining live patients have had renal transplants for five years.

Angiotensin-converting enzyme inhibitors

In summary, ACE inhibitors are effective in reducing blood pressure as initial therapy in some hypertensive patients and in combination with diuretics and other agents in virtually all hypertensives. ACE inhibitors are uniquely advantageous because of their favorable hemodynamic effects, the lack of adverse metabolic effects, and their ability to prevent or blunt undesirable effects of diuretic therapy. Their safety in large numbers of hypertensives has been consistently demonstrated. The minor nature of most side effects and the rarity of life-threatening side effects of ACE inhibitors is reassuring. Clinical experience has provided information about patients likely to be at high risk for side effects with ACE inhibitors enabling avoidance of the drugs, or the use of small doses and careful scrutiny in such individuals. The development of this new class of drugs permits safe and effective blood pressure control with potential enhancement of the sense of well being and quality of life to a degree never before encountered.

The renin-angiotensin systems

The renin-angiotensin systems are important regulators of cardiovascular homeostasis and participate in a variety of pathological conditions. Recent advances have not only clarified the functioning of the systemic renin cascade but have also indicated the importance of the generation of angiotensin in tissues.

Reduction of proteinuria by angiotensin converting enzyme inhibition

The effects of the angiotensin converting enzyme (ACE) inhibitor lisinopril on blood pressure, proteinuria and renal hemodynamics were evaluated in 13 patients with renal disease of different origin. A comparison was made with the effects of conventional antihypertensive therapy. Both drug regimens significantly lowered blood pressure, while only after 12 weeks of treatment with lisinopril, blood pressure was significantly lower than during conventional therapy. Lisinopril reduced proteinuria (by 61 +/- 40%), whereas conventional therapy had no significant effect on protein excretion. During the first eight weeks of treatment with lisinopril, there was a comparable degree of blood pressure reduction with both treatment regimens, whereas urinary protein loss was significantly less during ACE inhibition. There was only a nearly-significant positive correlation between the fall in proteinuria during lisinopril and the concomitant decrease in mean arterial pressure. Glomerular filtration rate decreased from 26.3 +/- 11.6 to 20.6 +/- 9.4 ml/min during treatment with lisinopril. This decrease was not correlated with the fall in proteinuria. A significant positive correlation existed between the fall in urinary protein excretion and both the decrease in overall renal vascular resistance, and the fall in filtration fraction. Although blood pressure lowering by itself could contribute to the antiproteinuric effect of lisinopril, our results suggest that this effect of ACE inhibition is also due to efferent (postglomerular) vasodilation. We conclude that the ACE inhibitor lisinopril effectively reduces blood pressure and proteinuria in renal disease. The latter effect is not only the result of a lower blood pressure, but is probably also due to a fall in intraglomerular capillary pressure.

Converting enzyme inhibition and kidney function in normotensive diabetic patients with persistent microalbuminuria

The effects of a long term reduction in blood pressure on the kidney function of normotensive diabetic patients who had persistent microalbuminuria (30-300 mg albumin/24 hours) were studied in two groups of 10 such patients before and during six months of treatment with either 20 mg enalapril or placebo daily. Treatments were assigned randomly in a double blind fashion. Before treatment both groups had similar clinical characteristics, weight, diet, total glycosylated haemoglobin, median albumin excretion rate (enalapril group 124 mg/24 h, placebo group 81 mg/24 h), and mean arterial pressure (enalapril group 100 (SD 8) mm Hg, placebo group 99 (6) mm Hg). During treatment weight, urinary urea excretion, and total glycosylated haemoglobin remained unchanged. The mean arterial pressure decreased in the enalapril group but not in the placebo group (enalapril group 90 (10) mm Hg, placebo group 98 (8) mm Hg). The median albumin excretion rate also fell in the enalapril group but not in the placebo group (enalapril group 37 mg/24 h, placebo group 183 mg/24 h.) The glomerular filtration rate rose in the enalapril group from 130 (23) ml/min/1.73 m2 to 141 (24) ml/min/1.73 m2, and total renal resistances and fractional albumin clearance decreased while fractional albumin clearance increased in the placebo group. These results show that in patients who have diabetes but not hypertension a reduction in blood pressure by inhibition of converting enzyme for six months can reduce persistent microalbuminuria, perhaps by decreasing the intraglomerular pressure.

Treating hypertension in non-insulin-dependent diabetes: a comparison of atenolol, nifedipine, and captopril combined with bendrofluazide

Twenty-five of thirty NIDDS who remained hypertensive (diastolic greater than 95 mmHg supine) after 4 weeks on bendrofluazide 2.5 mg daily (B), completed a single-blind, observer-blind randomized crossover study, in which the additional use of atenolol (50 mg daily) (A), slow-release nifedipine (20 mg twice daily) (N), and captopril (25 mg twice daily) (C) was compared. Patients took each drug for 8 weeks with dose doubling at 4 weeks if supine diastolic remained greater than 90 mmHg. All three combinations were more effective than bendrofluazide alone (p less than 0.01). In nine patients studied 2 h after tablets at the end of each treatment period nifedipine was more effective than the other two drugs (B:174/104 mmHg, A:162/95 mmHg, -8%, N:141/88 mmHg, -17%, C:157/94 mmHg, -10%, supine), whereas in 16 patients studied 15 h after their evening dose there was no significant difference. Fasting insulin and HbA1 levels were not significantly different between groups. No drug had a significant adverse effect on creatinine, glomerular filtration rate, overnight urinary albumin excretion or foot transcutaneous oxygen levels (43 degrees C). All three drugs studied were effective without deleterious effects on renal function or peripheral blood flow.

Angiotensin converting enzyme inhibitors in the treatment of hypertension: efficacy, metabolic effects and side effects

Angiotensin converting enzyme (ACE) inhibition is increasingly used as monotherapy for hypertension, especially because of the minimal side effects. Combination of ACE inhibitor therapy with diuretics has several practical and theoretical advantages.

Glucose metabolism during captopril mono- and combination therapy in diabetic hypertensive patients: a multiclinic trial

The effects of captopril monotherapy and combination therapy with thiazide diuretics or with methyldopa on glucose tolerance test (GTT) were investigated in 71 diabetic hypertensives. After the baseline evaluation, captopril (37.5-75 mg/day) was given. GTT and insulin assay were performed again between 10 and 12 weeks after the initiation of captopril therapy. We also studied the effects of chronic captopril therapy (6-12 months) on GTT in patients with essential hypertension. Captopril was well tolerated in all patients and no adverse reactions were observed. Chronic captopril therapy produced a significant (p less than 0.01) fall of blood pressure in all patients. There was no significant deterioration of the insulinogenic index or the time course curves of plasma glucose and insulin after GTT. These results indicate that captopril therapy does not affect glucose metabolism. Thus captopril may have an advantage for clinical use in hypertensive patients with or without impaired glucose metabolism.

Renal effects of angiotensin converting enzyme inhibitors in hypertension

This review focuses on the renal effects of the angiotensin converting enzyme inhibitors, captopril and enalapril. Emphasis is placed on the renal response to these drugs in patients with primary essential hypertension, and in hypertension accompanying renal parenchymal disease. Specifically reviewed are the renal function and hemodynamic, salt and water, body fluid composition, and urinary protein excretion responses. The interruption of the renin-angiotensin-aldosterone axis has the potential to produce a variety of favorable renal responses, including reduction of renal vascular resistance, enhancement of renal blood flow, enhancement of glomerular filtration rate, acute natriuresis, sustained diuresis, and a decrease in urinary protein excretion. Data in support of these potential renal perturbations are presented and discussed. The results suggest that the angiotensin converting enzyme inhibitors are important therapeutic agents in the treatment of hypertensive disease, in that they may modify pathophysiologic renal abnormalities encountered in this disease state.

Effects of nonsteroidal anti-inflammatory drugs on proteinuria

Most nonsteroidal anti-inflammatory drugs are anti-proteinuric agents, especially if the patient is sodium-depleted. The decline in urinary protein excretion induced by these agents always markedly exceeds the decrease in glomerular filtration rate. Moreover, the remaining proteinuria appears to be more selective. Together, these findings suggest that the anti-proteinuric effect of nonsteroidal anti-inflammatory drugs is hemodynamically mediated. Nonsteroidal anti-inflammatory agents that reduce renal prostaglandin E2 excretion also decrease proteinuria, whereas sulindac decreases neither prostaglandin E2 nor protein excretion. In a retrospective study, it appeared that administration of indomethacin improved renal survival of nephrotic patients with an initial serum creatinine concentration of less than 110 mumol/liter. The anti-proteinuric effect of indomethacin itself or indomethacin-induced hemodynamic changes might explain this observation.

Beneficial effects of angiotensin converting enzyme inhibition on renal function in patients with diabetic nephropathy

The effects of angiotensin converting enzyme inhibition with captopril were investigated in patients with diabetic nephropathy and hypertension. After nine days' treatment with captopril glomerular filtration rate was unchanged in 13 patients, whereas renal plasma flow had increased from 265 to 302 ml/min/1.73 m2 body surface area (p less than 0.05) and the filtration fraction had decreased from 14.3 to 12.8% (p less than 0.025). During two years' treatment with captopril in 14 patients the mean arterial blood pressure had fallen by 5 mm Hg (p less than 0.005) and the deterioration in glomerular filtration rate had decreased from 10.3 to 2.4 ml/min/year (p less than 0.005). There was no correlation between the fall in blood pressure and the reduction in the deterioration of glomerular filtration rate. These findings suggest that the effects of angiotensin converting enzyme inhibition on renal haemodynamics protect renal function. Inhibitors of angiotensin converting enzyme should be considered for lowering blood pressure in patients with diabetic nephropathy.

Effect of captopril on kidney function in insulin-dependent diabetic patients with nephropathy

The influence of angiotensin II on kidney function in diabetic nephropathy was assessed by studying the effect of 12 weeks' monotherapy with captopril (25-50 mg twice a day) in 16 hypertensive insulin dependent diabetic patients with persistent albuminuria. In an initial one week randomised single blind trial of captopril versus placebo, captopril (for nine patients) reduced arterial blood pressure from 148/94 (SD11/6) to 135/88 (8/7) mm Hg (p less than 0.05) and albuminuria from 1549 (range 352-2238) to 1170 (297-2198) micrograms/min (p less than 0.05), while glomerular filtration rate remained stable. No significant changes occurred in seven patients treated with placebo. During the 12 weeks of captopril treatment arterial blood pressure in all patients fell from 147/94 (11/6) to 135/86 (13/7) mm Hg (p less than 0.01), albuminuria fell from 1589 (range 168-2588) to 1075 (35-2647) micrograms/min (p less than 0.01), and glomerular filtration rate fell from 99 (SD19) to 93 (25) ml/min/1.73 m2 (p less than 0.01). The renin-angiotensin system showed suppressed plasma concentrations of angiotensin II and increased concentrations of angiotensin I and renin. The study showed that glomerular filtration rate is not dependent on angiotensin II, that captopril reduces albuminuria, probably by lowering glomerular hypertension, and that captopril represents a valuable new drug for treating hypertension in diabetics dependent on insulin with nephropathy.

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)