The Effectiveness and Safety of Doxazosin GITS in Hypertension when Added to non-Responders to Monotherapy

ABSTRACT

BACKGROUND AND OBJECTIVES: Doxazosin GITS (Gastrointestinal Therapeutic System) greatly minimizes the need for titration by changing the drug-delivery rate and pharmacokinetic profile. No data are available on the safety and efficacy of Doxazosin GITS among Korean hypertensive patients. This study was designed to evaluate the effectiveness and safety of Doxazosin GITS as an add-on therapy, under standard usage conditions, through a multi center study in patients with hypertension. SUBJECTS AND METHODS: A total of 595 hypertensive patients, not adequately controlled with a single agent, were enrolled into this study. The demographic profiles were gathered at the baseline, and the patients followed up at 4 and 8 week intervals for dose adjustment and for final assessment of the efficacy, respectively. The blood pressure, heart rate, fasting glucose and lipid profiles were assessed at each visit and any adverse events also observed. RESULTS: A total of 595 patients, in whom Doxazosin GITS had been administered, and evaluated at least once according to its related parameters, were analyzed to assess its safety. Of the 595 patients 534 completed this study and fulfilled the requirements for the efficacy analysis. Eight weeks after treatment, the responders (BP<140/90 mmHg or BP<130/85 mmHg in patients with diabetes) were 68.5% of the total patients and 71.3% of the hypertensive patients without diabetes. The blood pressure was significantly improved, with a mean change from the baseline of -18.9+/-19.5/-1 0.6+/-11.8 mmHg (mean+/-standard deviation expressed as SBP/DBP)(p<0.05). In addition, Doxazosin GITS showed a change in the heart rate of -1.5+/-6.8 bpm (p<0.05), and brought favorable metabolic effects, such as improved glucose metabolism and reductions in the total cholesterol and triglyceride. A total of 18 adverse events were reported among the 595 patients (3.0%), with mild to moderate severity. CONCLUSION: Doxazosin GITS as an add-on therapy significantly improved the blood pressure and heart rate, with favorable metabolic effects. Doxazosin GITS could be a safe and effective drug for hypertension not adequately controlled with a single agent.