Background and objective: Cognitive impairment occurs more frequently in hypertensives than in normotensive individuals. Early signs of cognitive impairment are predictors of dementia in late life. Felodipine is capable of almost normalizing plasma viscosity, which is elevated in most of hypertensive patients, thus improving microcirculation. The aim of this study was to evaluate whether this hemorheologic property of felodipine in addition to its blood pressure lowering effect can improve cognitive performance in hypertensive patients.
Patients and methods: Randomized, double-blind comparison between felodipine 10 mg and hydrochlorothiazide 50 mg amiloride 5 mg (HCT/amiloride) in patients 50-70 years of age with impaired cognitive function (c.l. test 1-2 points) and with resting blood pressure values of diastolic > 95 and < or = 115 mmHg and/or systolic > 160 and < or = 210 mmHg. Blood pressure measurements and evaluation of total short term storage capacity were done at the beginning and after 12 weeks of treatment.
Results: 31 patients (14 felodipine and 17 HCT/amiloride) were included in the per protocol analysis. Blood pressure values at the beginning and after 12 weeks of treatment were (mmHg): for felodipine systolic 168 +/- 4 and 150 +/- 6 (p < 0.01), diastolic 108 +/- 3 and 88 +/- 4 (p < 0.001). For amiloride/HCT systolic 173 +/- 8 and 150 +/- 10 (p < 0.01), diastolic 105 +/- 5 and 88 +/- 5 (p < 0.001). Short term storage capacity improved by 15 +/- 6 bits during felodipine treatment (p < 0.001) and by 9 +/- 9 bits during amiloride/HCT treatment (p < 0.05). Thus cognitive improvement was superior by 67% in the felodipine group compared to amiloride/HCT (p < 0.05).
Conclusion: In this study a pronounced improvement of mental performance occurred in patients treated with felodipine. Since the cognitive gain was significantly superior to amiloride/HCT treatment there must be an additional blood pressure-independent effect of felodipine, such as enhancing microcirculation. Whether these properties possibly counteract the development of dementia in hypertensives has to be evaluated in long term studies in more patients.