title: Effects of efonidipine, an L- and T-Type dual calcium channel blocker, on heart rate and blood pressure in patients with mild to severe hypertension: an uncontrolled, open-label pilot study.
abstract: BACKGROUND
  Dihydropyridines (DHPs), a type of calcium channel blocker (CCB), are commonly prescribed for the treatment of hypertension and angina pectoris. DHPs act mainly on L-type calcium channels, essentially causing reflex tachycardia (elevated heart rate [HR]), which negatively affects cardiac function. Because T-type calcium channels in the sinoatrial node attenuate reflex tachycardia, a dual L- and T-type CCB (eg, efonidipine hydrochloride) may favorably affect cardiac pacing, thereby reducing reflex tachycardia. The effect of efonidipine as a DHP on HR deserves special consideration with regard to reflex tachycardia.
  
  
  OBJECTIVE
  The aim of this study was to determine whether the L- and T-type CCB efonidipine can decrease the elevated HR induced by prior treatment using traditional DHPs.
  
  
  METHODS
  This uncontrolled, open-label pilot study was conducted at the Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine (Tokyo, Japan). Patients aged 48 to 80 years with mild to severe hypertension and angina pectoris and who were receiving therapy with a DHP other than efonidipine were eligible. During an 8-week observation period, patients continued therapy with their DHP. After those 8 weeks, therapy was switched to oral efonidipine (40-mg tablet once daily) in patients whose blood pressure (BP) was stable and well controlled and whose HR was >80 bpm. BP and HR were monitored every 4 weeks of treatment with efonidipine.
  
  
  RESULTS
  Eighteen patients (12 men, 6 women; mean [SD] age, 62.6 [12] years) were enrolled. After the switch to efonidipine, mean (SD) HR decreased significantly, from 94 (7) bpm to 86 (11) bpm at 12 weeks (P<0.05). The antihypertensive effect of efonidipine was similar to that of the DHPs used before the switch to efonidipine therapy, and reflex tachycardia was attenuated.
  
  
  CONCLUSIONS
  In this study of a small sample of patients with mild to severe essential hypertension and angina pectoris, efonidipine was as effective as other DHPs. Moreover, the drug attenuated the reflex tachycardia that occurred with traditional DHPs.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Mitsuyuki
authors.initials: M
authors.lastname: Shimizu
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ogawa
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Uehara
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Otsuka
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okumura
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kusaka
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Hasuda
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Yamada
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Seibu
authors.initials: S
authors.lastname: Mochizuki
keywords: T-type calcium channel; calcium channel blocker, reflex tachycardia; efonidipine; heart rate; hypertension