Renal responses to nifedipine and captopril in hypertensive insulin-dependent diabetic men - a randomized cross-over study

Q: Were there acute renal haemodynamic differences between the two agents?

The initial renal responses to both agents were similar, with increases in renal plasma flow and a non-significant decline in glomerular filtration rate, leading to comparable decreases in filtration fraction.

Sep 25, 2026

Uploaded by Eliana

Renal haemodynamic effects of nifedipine retard and captopril were tested in a double-blind randomized cross-over trial involving 10 hypertensive insulin-dependent diabetic men. Acute responses to nifedipine 20 mg and captopril 25 mg were assessed at baseline and after 8 weeks of chronic dosing. Blood pressure decreased on both regimens, renal plasma flow and filtration fraction changed differently after captopril, and neither drug significantly altered urinary albumin excretion after 8 weeks.

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# Original Article Renal responses to nifedipine and captopril in hypertensive insulin- dependent diabetic men:a randomized cross-over study D.A.S.Jenkins,P.Cowan,A.W.Patrick and B.F.Clarke Medical Renal Unit and Diabetic Department,Department of Medicine,Edinburgh Royal Infirmary,Edinburgh,UK Abstract.The effects of nifedipine retard and captoprilon renal haemodynamic parameters have been exam-ined in a double blind randomised cross-over trial in10 insulin-dependent diabetic males with hypertension(systolic pressure >150 mmHg or diastolic pressure>90 mmHg).The acute renal haemodynamic responseto nifedipine retard 20mg and captopril 25 mg wasmonitored at the start of therapy and again after 8weeks treatment with nifedipine retard 20 mg b.d.andcaptopril 25 mg b.d.Blood pressure fell from148/97±4/2 (SEM)during the run-in phase to135/87±4/1.5 on nifedipine retard and to 131/83±5/1on captopril.There was no difference between theinitial renal response to the two agents;an increase inrenal plasma flow and a non-significant decline inglomerular filtration rate resulted in similar decreasesin filtration fraction.After 8 weeks therapy,neitherdrug had a significant effect on urinary albumin excre-tion.Baseline renal function did not differ and noacute changes in renal haemodynamics were seen afternifedipine.Following captopril there was no acutechange in systemic blood pressure but RPF rose from572±41 to 638±42 ml/min per 1.73 m²(P<0.05)andfiltration fraction fell from 0.21 to 0.16(P<0.02).Thissustained acute response of the renal circulation toangiotensin-converting enzyme(ACE)inhibition afterchronic therapy may be relevant to the apparent renalprotection afforded by ACE inhibitors in experimentalnephropathies. Key words:diabetes mellitus;hypertension;renalhaemodynamics;captopril;nifedipine ## Introduction There is no doubt that effective treatment of hyperten-sion is of benefit to patients with insulin-dependentdiabetes and may delay the progress of renal impair-ment in diabetic nephropathy.Two studies have Downloaded from https/academic.oupcom/ndtarticle-abstrac8/3/200/1927572by guest on 24 October 2019 documented a decline in the rate of deterioration ofglomerular filtration rate(GFR)and a reduction inurinary albumin excretion achieved by control ofblood pressure with standard antihypertensive therapy [1,2].It is,however,more controversial whether onespecific class of antihypertensive agent is more effect-ive than another.Angiotensin-converting enzyme(ACE)inhibitors were reported to reduce proteinuriain diabetic patients with nephropathy [3]and sub-sequently in an animal model to lower glomerularcapillary pressure and protect against glomerulo-sclerosis [4].When captopril was compared to astandard antihypertensive regime of hydralazine,reserpine,and hydrochlorothiazide in the streptozoto-cin diabetic rat,the captopril-treated group hadgreater protection against nephropathy than thatachieved by standard therapy [5].A number of reportshave documented an improvement in albumin excre-tion and reduction in the rate of deterioration ofGFR in diabetic patients given ACE inhibitors [6-10];however,in all of these studies there is no way ofisolating the improved systemic blood pressure fromanalysis of the effect of the drug on the kidney.Rudberg et al.[11]demonstrated a reduction inalbuminuria in both normotensive and hypertensivediabetic patients and concluded that this reductionwas independent of blood pressure changes.Nifedip-ine has been reported to increase urinary albuminexcretion [12]in comparison to captopril,while intwo further comparative trials in diabetic patients,ACE inhibitors were not found to have any advantageover calcium antagonists of the dihydropyridine group[13,14].Despite the theoretical advantages of loweringintraglomerular pressure with ACE inhibition [4,5],there has been no proven benefit in human studies todate.There is no detailed comparison of the effect oftwo commonly prescribed antihypertensiv

FAQs

Were there acute renal haemodynamic differences between the two agents?

The initial renal responses to both agents were similar, with increases in renal plasma flow and a non-significant decline in glomerular filtration rate, leading to comparable decreases in filtration fraction.

Sep 25, 2026

Uploaded by Eliana