The effects of a nonselective beta-adrenergic blocking drug with beta-2 agonist activity (dilevalol 200 mg) on proteinuria and renal hemodynamics were evaluated in a double-blind crossover study versus an ACE inhibitor (enalapril 5 mg) in eight patients with glomerulonephritis, moderate renal function impairment and proteinuria > 1 g/24 hr. Patients were studied after a one week placebo phase while off all other medications, except steroids in a few cases, and after three weeks of treatment. A 10-day placebo washout period was included between the various drug treatments. During each period renal hemodynamics were measured by clearance techniques, and urinary protein excretion as well as fractional clearance of albumin and IgG were determined. Both drugs reduced mean arterial pressure and proteinuria to a similar extent [mean arterial pressure: placebo 108 +/- 13 mm Hg; dilevalol 103 +/- 11 mm Hg (P < 0.05); enalapril 103 +/- 12 mm Hg (P < 0.05); protein excretion: placebo 5.1 +/- 4.2 g/day; dilevalol 3.3 +/- 3.0 g/day (P < 0.05); enalapril 2.8 +/- 2.8 g/day (P < 0.05)]. The antiproteinuric effect was greater with enalapril than dilevalol. Dilevalol reduced GFR [baseline inulin clearance: 73.3 +/- 38 ml/min/1.73 m2; after dilevalol: 63.3 +/- 28 ml/min/1.73 m2 (P < 0.05)] and the decrease of proteinuria correlated positively with the reduction of GFR. Enalapril did not significantly lower the GFR (inulin clearance during enalapril 66.8 +/- 23 ml/min/1.73 m2) and the reduction of proteinuria did not correlate with the lowering of the GFR. Renal blood flow was not significantly changed either by enalapril or by dilevalol (baseline levels of PAH clearance: 363 +/- 182 ml/min/1.73 m2; after dilevalol 382 +/- 185 ml/min/1.73 m2 and after enalapril 397 +/- 159 ml/min/1.73 m2). Enalapril reduced the albumin excretion rate but dilevalol did not [baseline levels: 1.5 +/- 1.0 mg/min, dilevalol 1.3 +/- 1.0 mg/min, enalapril 0.9 +/- 1.2 mg/min (P < 0.05)]. In conclusion, both drugs reduce proteinuria in patients with moderate renal function impairment and proteinuria > 1 g/24 hr and show similar effects on hemodynamics. This reduction is supposed to be related to a reduction of GFR and FF in case of dilevalol. Enalapril showed a more pronounced reduction of proteinuria, which could be based on an increased charge selectivity of the glomerular barrier.
