Effects of efonidipine hydrochloride on renal parenchymal hypertension: Evaluation by 24-hour ambulatory blood pressure monitoring

Although blood pressure (BP) control in renal parenchymal hypertension constitutes one of the most important therapeutic strategies not only to halt the progression of renal damage but also to prevent other organ injury, circadian BP variation should also be taken into consideration for these purposes. Both angiotensin converting enzyme inhibitors and angiotensin II receptor blockers are recommended for the treatment of hypertension with renal disease. Furthermore, calcium channel blockers (CCBs) are also useful in the treatment of hypertension with renal disease, since CCBs are well tolerated and exert beneficial action because of its high efficacy and less adverse effects on renal function in the presence of impaired renal function. We therefore examined the antihypertensive effect of a CCB efonidipine hydrochloride which possesses renal protective action of particular efficacy on BP with special reference to circadian variation and drug safety in patients with renal parenchymal hypertension. After evaluation of inclusion and exclusion criteria, in-patients with renal parenchymal hypertension were treated with efonidipine hydrochloride for 4-16 days at a starting dose of 20 mg/day (once a day) up to a maximal dose of 60 mg/day as required to obtain optimal BP control. BP and pulse rates were measured hourly for more than 24 hours at the end of the observation period and the treatment period using automatic ambulatory BP monitoring device, and laboratory parameters including serum creatinine and creatinine clearance, as well as subjective and objective symptoms, were assessed during each period. In 10 patients, the treatment with efonidipine hydrochloride significantly reduced the mean values of circadian variation of systolic (-11.1 mmHg) and diastolic BP (-6.7 mmHg), although no significant change was noted in the range of circadian BP variation or any effect on the mean values and range of circadian variation of pulse rates. In 14 subjects assessed for safety, no untoward effect on renal parameters such as serum creatinine and creatinine clearance was observed, although mild adverse events were seen in 4 cases, including adverse drug reactions (2 cases). In conclusion, the present study indicates that efonidipine hydrochloride (20-60 mg/day), when administered once a day after breakfast, exerts potent and sustained depressor action, but causes less adverse effect in renal parenchymal hypertension.