Scintigraphic evaluation of the short- and long-term renal effects of oral felodipine using technetium-99m-mercaptoacetyl triglycine.
The short- and long-term effect of felodipine on renal perfusion and tubular function was investigated using a new renal tubular imaging agent, 99mTc-mercaptoacetyl triglycine (99mTc-MAG3). Twelve patients with essential hypertension (mean age = 49 +/- 8 years) were studied. Renal scintigraphies with 180 MBq 99mTc-MAG3 were performed at baseline, at the 2nd hour following oral administration of 5 mg felodipine and 4 weeks later on 5-10 mg daily felodipine therapy. The time-activity curves of each kidney were obtained following background subtraction. The 99mTc-MAG3 clearance value was measured for each kidney. In addition, perfusion index (PI), reno index, time to maximum, half-maximum and two thirds of maximum activity values of each kidney were calculated. Systolic and diastolic blood pressures were significantly lowered with long-term administration of felodipine (from 159 +/- 12/105 +/- 5 to 141 +/- 11/87 +/- 7 mm Hg, p = 0.01 and p = 0.002, respectively). Heart rate did not change significantly. Initially, a decrease in PI indicating an increase in renal blood flow (from 246 +/- 96 to 194 +/- 54, p = 0.01) was observed, whereas no change was noted during the chronic administration (to 230 +/- 69, p = NS). Total clearance of 99mTc-MAG3 was decreased nonsignificantly following the initial dose of felodipine (from 361 +/- 93 to 351 +/- 91 ml/min, p = NS). During long-term therapy, felodipine did not alter the perfusion and tubular function of the kidneys. Our results indicated that felodipine causes a significant increase in renal blood flow initially, even with a nonsignificant change in systemic blood pressure.
Ozdemir
O
O
Department of Internal Medicine, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
Erbas
B
B
Ugur
O
O
Varoglu
E
E
Erbengi
G
G
Bekdik
C
C
Oram
E
E
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D015736:Felodipine / Q000008:administration & dosage*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000503:physiopathology; D007668:Kidney / Q000000981:diagnostic imaging* / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D011866:Radioisotope Renography; D017263:Technetium Tc 99m Mertiatide; D013997:Time Factors
D017263:Technetium Tc 99m Mertiatide; D015736:Felodipine