COMBINED EFFECT OF A LOW-FAT DIET AND DOXAZOSIN ON BLOOD-PRESSURE CONTROL AND BLOOD-LIPIDS

Doxazosin, a once daily alpha-blocking drug has been demonstrated to r educe both BP and hyperlipidaemia, related risk factors for premature vascular disease. This study was designed to see if a low fat diet alt ered the favourable effect of doxazosin on blood lipids in adults with mild to moderate hypertension and mild to moderate hypercholesterolae mia (5.6-8.0 mmol/l). Following a six week period on a low fat diet, p atients were randomly allocated to additional doxazosin (2-8 mg/day) o r enalapril (5-20 mg/day) treatment for a further 10 weeks. Forty-four of 55 subjects completed the study. A low fat diet reduced mean body weight by 2 kg without significantly altering blood lipids (total and HDL cholesterol, triglycerides). Doxazosin (4.5 +/- 2.9 mg/day) and en alapril (12.5 +/- 6.5 mg/day) produced a comparable lowering of sittin g and standing BP at all visits and also produced similar 24h BP contr ol. The expected increase in HDL cholesterol concentration previously noted in this patient population in association with doxazosin treatme nt was not detected suggesting that the low cholesterol-high carbohydr ate diet, at least acutely, attenuates this potentially beneficial eff ect on plasma lipids. In summary, doxazosin has a comparable tolerabil ity and BP lowering ability to enalapril. However, its ability to incr ease HDL cholesterol may be reduced in patients on low fat diets.