Chronobiologic Evaluation of the Efficacy of a New Calcium Antagonist, Nicardipine Hydrochloride, in Essential Hypertension

Purpose: The efficacy of a newly developed calcium antagonist, nicardipine hydrochloride, was evaluated to essential hypertension chronobiologically.Methods: Thirteen patients with essential hypertension (7 male, 6 female; age range, 34-74yrs) were examined by the ambulatory blood pressure monitoring of Nippon Colin (Komaki, Japan). The monitoring was performed before the treatment for 48hr. Each patient was subsequently started on nicardipine hydrochloride twice daily for 1wk. The monitoring was repeated similarly thereafter. The least-square fit of a cosine with a period of 24hr was calculated to obtain MESOR, amplitude and acrophase. These data were evaluated comparing with chronodesm obtained from 334 Japanese in our laboratory.Results and conclusions: 1) The drug was well tolerated. While blood pressure reduction was observed throughout the day, it was rather uniform and less reduced the blood pressure during night rest span and did suppress active span rise of the blood pressure. 2) This provided that the pharmacokinetic value showed a discrepancy from the pressure value and it could not predict the efficacy of the pressure reduction. 3) Therefore, the chronobiological evaluation of this drug was essential to start the antihypertensive therapy. Chronotherapy was imperative by this type of the therapy.