Treating hypertensive diabetics: a comparison of verapamil and metoprolol in black and white patients.

Ca2+ antagonists may be particularly effective in "low-renin" patients, including black subjects and diabetics, as metabolically sound antihypertensive therapy. This paper reports a double-blind randomized crossover trial of verapamil SR (to 240 mg b.i.d.) versus metoprolol (to 100 mg b.i.d.) in 20 black and 15 Caucasian non-insulin-dependent patients with entry blood pressures (BP) greater than 160/90 mm Hg. Mean age was 61 +/- 4.8 years; duration of diabetes 5.8 +/- 4.9 years. Each subject took 4 weeks placebo, then two 6 week active phases, with an intervening 2 week washout. Erect (E)/lying (L) BP, weight, and fasting blood were taken at each visit with overnight urine collections. In blacks mean entry BP (L) +/- SD were 165.8 +/- 16/98.7 +/- 11 mm Hg. On verapamil BP (L) fell significantly by -12.6 +/- 16/-6.6 +/- 9.7 mm Hg (p less than 0.01), but there was no overall fall on metoprolol (+1.65 +/- 14.5/-1.3 +/- 9.7 mm Hg). Heart rates fell on both drugs from 76.1 +/- 18.3 to 68.4 +/- 11 and 59.4 +/- 7.6 beats/min, respectively, indicating tablet compliance. In whites, BP fell on both drugs, as did heart rates. Changes in HbA1c, plasma glucose, and renin were statistically insignificant. Change in BP was unrelated to initial renin levels in either blacks or whites. In blacks, mean entry urine Na, K, and Ca were 77.4 +/- 39.3, 20.9 +/- 10, and 2.35 +/- 1.5 mmol/l and in whites 84.1 +/- 42, 22 +/- 17.2, and 3.56 +/- 3.2 mmol/l, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)