Quality of life and calcium channel blockade with nifedipine GITS versus amlodipine in hypertensive patients in Spain

Objective Compliance with hypertension treatment is affected by treatment-r elated factors (complexity, side effects), efficacy and compound-specific e ffects that impact on quality of life. This study examined the differences in quality of life produced by two once-daily calcium channel blockers usin g different delivery systems: nifedipine gastrointestinal therapeutic syste m (GITS) and amlodipine. Design This was a double-blind, double-dummy, randomized clinical trial com paring nifedipine GITS (30 mg) and amlodipine (5 mg) for 24 weeks following a placebo run-in. Clinical, laboratory evaluations and quality-of-life dat a were assessed at screening, baseline randomization and three times during active therapy. Setting The study was conducted in 13 medical clinics in Spain. Patients The sample comprised 430 screened and 356 randomized patients with mild to moderate hypertension (diastolic blood pressure 95-114 mmHg), Main outcome measures Change in systolic and diastolic blood pressure and i n health-related quality of life were the main outcome measures. Results There were no significant differences between active treatment grou ps in the blood pressure changes (systolic blood pressure: nifedipine GITS -15.5 mmHg; amlodipine -15.7 mmHg), Spontaneous adverse events consistent w ith calcium channel blockage were not different. The nifedipine GITS group improved in all quality-of-life measures except Sexual Symptom Distress and showed a significantly greater improvement than amlodipine in overall Qual ity of Life (P < 0.05), General Perceived Health (P< 0.026) and its subscal e Vitality (P < 0.019). The amlodipine group declined in overall Quality of Life, General Perceived Health, Vitality and Sleep Disturbance, and signif icantly in Sexual Symptom Distress (P< 0.045). However, this group improved in self-reported Cognitive Functioning (P= 0.036), Mental Acuity (P< 0.005 ) and Detachment/disorientation (P= 0.01), Conclusions These results suggest compound-specific effects on quality of l ife that may be due to differences in the delivery system. Nifedipine GITS is short-acting (2 h half-life) and is delivered continuously over a 24 h p eriod, while amlodipine has a half-life of 40 h, which may produce more sus tained low-revel effects, While a more beneficial profile was observed for nifedipine, amlodipine demonstrated potential positive effects on cognitive functioning. (C) Lippincott Williams & Wilkins.