Effects and Safety of Doxazosin in Mild to Moderate Essential Hypertension

The study was performed to evaluate the antihypertensive effectivity and safety of a new alpfa-1 adrenergic receptor antagonist, doxazosin, in patients with mild to moderate essential hypertension. Twently patients above 18 years of age and a diastolic blood pressure between 95-115 mmHg under no antihypertensive medication made up the study population. Eleven were female, 9 were male and the mean age was 41.2±11.4 (range: 31-68). Following a 2-week placebo period, they were started on doxazosin, 1 mg/day, and the dose was adjusted to a maximum of 8 mg/day at controls performed by two week intervals Laboratory investigations involving blood biochemistry, lipid profile, complete blood count and urine analysis were performed both at the beginning and at the end of a 14 week long followup period. Five patients left the study on their own will due to nonmedical reasons. One patient had to be excluded from the study due to severe headache. The remaining 14 patients successfully completed the 14-week followup. There was no significant difference between blood pressure recordings obtained at entry to the study and at the end of the placebo period (159.6±213/103.1±6.9 mmHg vs 154.9±14.5/100.3 ± 4.9 mmHg, p>0.05). On the other hand, blood pressure values obtained at the 2nd week of doxazosin treatment were significantly lower than those recorded at entry (159.6±21.3/103.1±6.9 mmHg vs 140.8±9/90.4±8.5 mmHg, p<0.05). This antihypertensive effect was preserved during 14 weeks of followup and the blood pressure values recorded at the end of the study were significantly lower when compared to the beginning (137.2±9.9 / 88.0 ± 7.1 mmHg, p<0.005). The mean effective antihypertensive dose was 2.71±1.2 mg/day. No significant change was observed at the pulse rate values recorded throughout the followup period. No significant difference in any laboratory parameter except fasting blood glucose level was evident at the end of the study. The fasting blood glucose level tended to be higher after the therapy although the difference did not reach statistical significance (88.6 ± 11.9 vs 101.4±20.1 mg/dl, p=0.05). Total cholesterol, LDL-cholesterol, HDL-holesterol, trigliseride, apolipoprotein A1 and apolipoprotein B levels did not show any significant difference at the end of the followup period. The drug had to be stopped due to severe headache in only one patient. Two other patients described mild and spontaneously resolving side effects. No side effects were recorded in the remaining twelve. In conclusion, this study suggests that doxazosin is an effective and safe agent in the treatment of patients with to moderate essenital hypertension.