EFFECT OF LACIDIPINE, A DIHYDROPYRIDINE CALCIUM-ANTAGONIST ON RENAL-FUNCTION OF HYPERTENSIVE PATIENTS WITH RENAL-INSUFFICIENCY

There are few studies on the use of dihydropyridine calcium antagonist s in hypertensive patients with moderate renal insufficiency. We under took an open study on the effects on renal function, albumin excretion and blood pressure of the slow-onset, long-acting dihydropyridine cal cium antagonist, lacidipine, in 14 patients with stable, chronic renal insufficiency (mean assessed GFR 0.78 ml/s, range 0.50-1.17 ml/s) and moderate hypertension. Following a 2 week washout phase, lacidipine w as administered for 24 weeks in a dose of 2 mg/day with the dose being titrated at 2 weekly intervals to a maximum of 6 mg/day in order to a chieve adequate blood pressure control. Frusemide was introduced if bl ood pressure was not controlled on the maximum lacidipine dose. Blood pressure, creatinine clearance, 24 h urinary albumin excretion and pla sma creatinine and albumin concentrations were measured at regular int ervals throughout the study. Isotopic GFR was determined at the end of the washout period and at week 24. Lacidipine was not very effective in controlling blood pressure and had an adverse effect on renal funct ion. In 3 patients with an incipient nephrotic syndrome this necessita ted withdrawal from the study. Mean GFR of the 10 patients who complet ed the study decreased from 0.69 ml/s/1.73 m(2) at baseline to 0.56 ml /s/1.73 m(2) at week 24 (p = 0.006) with a decline in GFR being observ ed in 9 of these patients. The decrease in GFR was greatest in patient s with poorly controlled blood pressure. An insignificant increase in mean urinary albumin excretion occurred during the study with this inc rease being observed only in patients with albuminuria >1 g/24 h at ba seline. These findings indicated that systemic hypertension altered gl omerular hemodynamics and that the vasodilatation of pre-glomerular ve ssels which followed introduction of the calcium antagonist may have e xacerbated this situation. The withdrawal of an angiotensin converting enzyme inhibitor during the washout period may have contributed to th ese changes. We suggest that renal function should be monitored closel y in patients with renal insufficiency when a calcium antagonise is be ing used to control blood pressure, particularly in those with either marginal blood pressure control, significant albuminuria or an incipie nt nephrotic syndrome.