A double-blind and cross-over comparison of once daily doxazosin and placebo with steady-state pharmacokinetics in elderly hypertensive patients.

The alpha 1-adrenoceptor antagonist doxazosin has been compared with placebo in 40 elderly hypertensive patients (mean age 71.4 years). At the end of 10 weeks once daily treatment with doxazosin the mean 24-h post-dose changes in standing and supine blood pressure compared with placebo were -6.9/-5.6 mmHg (systolic/diastolic) and -6.2/-5.5 mmHg respectively. The reductions in standing and supine diastolic blood pressures were statistically significant compared with placebo. At the end of treatment steady-state pharmaco-kinetics were evaluated in 18 patients. The plasma elimination half-life during the dose interval in these patients was 16.1 h (range 10.1-27.1 h) and the median time to peak plasma concentration was 3 h (range 1-4 h). One patient was withdrawn because of adverse effects (headache, weakness, and sweating) during doxazosin treatment. Once daily doxazosin reduced diastolic blood pressure and was well tolerated in these elderly hypertensive patients.