Comparison of the efficacy of dihydropyridine calcium channel blockers in African American patients with hypertension. ISHIB Investigators Group. International Society on Hypertension in Blacks.
BACKGROUND
Hypertension is a prevalent disease among African Americans, and successful treatment rates are low. Since calcium channel blockers are well-tolerated and efficacious in African Americans, we undertook this study to compare the efficacy, safety, and tolerability of 3 commonly prescribed calcium channel blockers: amlodipine besylate (Norvasc), nifedipine coat core (CC) (Adalat CC), and nifedipine gastrointestinal therapeutic system (GITS) (Procardia XL).


METHODS
One hundred ninety-two hypertensive patients across 10 study centers were randomly assigned to double-blind monotherapy with amlodipine besylate (5 mg/d), nifedipine CC (30 mg/d), or nifedipine GITS (30 mg/d) for 8 weeks. Patients not achieving therapeutic response after 4 weeks had their dose doubled for the next 4 weeks. The primary end point was a comparison of the average reduction (week 8 minus baseline) in 24-hour ambulatory diastolic blood pressure (DBP). Secondary end points included a comparison of average 24-hour ambulatory systolic blood pressure (SBP), office SBP or DBP reduction, responder rates, safety, and tolerability.


RESULTS
One hundred sixty-three patients were evaluable for efficacy after 8 weeks. There was no significant difference in the average 24-hour ambulatory DBP (-8.5, -9.0, and -6.1 mm Hg, respectively) or SBP (-14.3, -15.7, and -11.8 mm Hg, respectively) reduction. Average office SBP and DBP were reduced to a comparable degree (19-22 mm Hg [P =.50] and 12-14 mm Hg [P =.51], respectively). Responder rates (DBP <90 or reduced by > or = 10 mm Hg) were similar (P = .38). Discontinuation rates and adverse event frequency were distributed similarly across the 3 treatment groups.


CONCLUSIONS
The efficacy, safety, and tolerability of the 3 dihydropyridine calcium channel blockers are equivalent in African Americans with stages 1 and 2 hypertension.
Hall
W D
WD
Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA.
Reed
J W
JW
Flack
J M
JM
Yunis
C
C
Preisser
J
J
D000328:Adult; D000368:Aged; D017311:Amlodipine / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000009:adverse effects / Q000627:therapeutic use*; D044383:Black People; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000009:adverse effects / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000208:ethnology*; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000627:therapeutic use; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D001741:Black or African American
D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; D017311:Amlodipine; D009543:Nifedipine