Long-Term Electrolyte Effects during Initiation of Antihypertensive Therapy with Amlodipine or Hydrochlorothiazide in Diabetic Nigerians

Information is scarce regarding the effects of amlodipine or hydrochlorothiazide therapy on serum and urine electrolyte profiles in hypertensive Nigerians with type 2 diabetes mellitus. Therefore, to evaluate whether amlodipine or hydrochlorothiazide would be preferable to initiate treatment, we randomized 40 newly diagnosed hypertensive subjects with controlled type 2 diabetes mellitus aged 43-68years to amlodipine and hydrochlorothiazide treatment groups of 20 patients each (10 males, 10 females), and they were treated respectively, with amlodipine 10mg and hydrochlorothiazide 25mg, both drugs being given once daily for 48 weeks. Body mass index, blood pressure, 24h urine volume, serum and urine electrolytes were assessed at baseline and at the end of weeks 1, 3, 6, 12, 24, 36 and 48. The two drugs significantly reduced blood pressure, though the effect of amlodipine was significantly greater compared with that of hydrochlorothiazide (P < 0.01). Diuresis was significant in hydrochlorothiazide group (P < 0.01). Observed male/female serum Na loss was 9.18±2.32/10.90±2.50 and 13.30±1.34/15.10±1.77mmol/L for amlodipine and hydrochlorothiazide subgroups, respectively. There was a parallel significant (P < 0.05) natriuresis. Significant (P < 0.05) hypokalemia occurred in hydrochlorothiazide subgroups and overall male/female serum K loss was 0.10/0.08 and 0.16/0.24mmol/L for amlodipine and hydrochlorothiazide, respectively. However, there was no significant parallel kaliuresis. Significant (P < 0.05) disproportionate hypochloremia occurred in all subgroups, so also was the parallel chloriuria. By providing effective blood pressure control and beneficial biochemical effects, amlodipine therapy appears suitable for treatment of hypertension in these diabetic patients. Similarly, low dose hydrochlorothiazide therapy, which seems to have more marked effects in females, appears to have moderate biochemical complications in these patients and is, therefore, a logical alternative to substitute for or add to amlodipine therapy.