Combined effect of a low fat diet and doxazosin on blood pressure control and blood lipids. Hunter Hypertension Research Group.

Doxazosin, a once daily alpha-blocking drug has been demonstrated to reduce both BP and hyperlipidaemia, related risk factors for premature vascular disease. This study was designed to see if a low fat diet altered the favourable effect of doxazosin on blood lipids in adults with mild to moderate hypertension and mild to moderate hypercholesterolaemia (5.6-8.0 mmol/l). Following a six week period on a low fat diet, patients were randomly allocated to additional doxazosin (2-8 mg/day) or 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 enalapril (12.5 +/- 6.5 mg/day) produced a comparable lowering of sitting and standing BP at all visits and also produced similar 24h BP control. The expected increase in HDL cholesterol concentration previously noted in this patient population in association with doxazosin treatment was not detected suggesting that the low cholesterol-high carbohydrate diet, at least acutely, attenuates this potentially beneficial effect on plasma lipids. In summary, doxazosin has a comparable tolerability and BP lowering ability to enalapril. However, its ability to increase HDL cholesterol may be reduced in patients on low fat diets.