Prazosin GITS vs sustained release nifedipine in patients with hypertension and abnormal lipid profile: a randomized, controlled, multicenter study. Madras Hypertension Study Group.

OBJECTIVE

To compare the long-term antihypertensive efficacy, tolerability, and metabolic effects of prazosin GITS and a sustained release (SR) preparation of nifedipine.

DESIGN

Randomized, controlled, multicenter study of 26 weeks duration.

SETTING

Office practices of 24 physicians in Chennai, Tamil Nadu, India.

PATIENTS

Males and females, aged 30 to 70 yrs, with hypertension of JNC V stage 1 or 2 at the end of a 2-week placebo run-in period, and an abnormal lipid profile. Sufficient number of patients recruited so that at least 60 complete the entire study.

INTERVENTIONS

Prazosin GITS (Minipress XL, 2.5-5 mg once daily) or sustained release nifedipine (Nicardia Retard 10-20 mg twice daily) for upto 6 weeks, continued upto 24 weeks in those showing a pre-defined response (SBP and/or DBP normalized, or DBP fall of at least 10 mm Hg with actual value of DBP < 95 mm Hg). Patients allocated to either of the two interventions by randomization.

OUTCOME MEASURES

Percent patients showing pre-defined BP response at week 6; percent patients with DBP < 90 mm Hg, SBP < 140 mm Hg, and both; percent patients with DBP fall > or = 10 mm Hg; mean fall in BP among those receiving treatment for 24 weeks; mean change in blood glucose and serum lipids at the end of weeks 8, 16, and 24 of treatment; frequency and intensity of adverse events judged probably or definitely related to the drug.

RESULTS

54 patients randomized to prazosin GITS group and 52 to nifedipine SR group. Of these, 39 in prazosin GITS group (M 23, F 16; mean age-50. 6 yr, SEM 1.66) and 36 in nifedipine SR group (M 20, F 16; mean age-52.3 yr, SEM 1.71) completed the study. Percent patients with DBP < 90 mm Hg at 24 weeks: prazosin GITS--100%, nifedipine SR--100%; SBP < 140 mm Hg: prazosin GITS--94.9%, nifedipine SR--91.7%; both DBP < 90 mm Hg and SBP < 140 mm Hg: prazosin GITS--92.3%, nifedipine SR--91.7%; percent patients with DBP fall of 10 mm Hg or more at 24 weeks: prazosin GITS--76.9%, nifedipine SR--83.3%. The mean fall in the systolic and diastolic blood pressure from the end-of-placebo-phase values to all the other time points was comparable in the 2 groups. Treatment with prazosin GITS did not produce any statistically or clinically significant change in the metabolic parameters at the end of 24 weeks, while with nifedipine SR there was a significant increase in the serum LDL values at 24 weeks (p = 0.009). Adverse events probably or definitely related to the drug: prazosin GITS--1.9%, nifedipine SR--2.1%.

CONCLUSION

Both drugs were equally effective and well tolerated. While prazosin GITS was neutral on serum lipids, use of nifedipine SR was associated with a significant increase in serum LDL cholesterol at the end of 24 weeks.