Numerous studies have demonstrated that antihypertensive agents differentially affect blood lipids. Thiazide diuretics increase total cholesterol, low-density lipoprotein, and triglycerides and cause a slight reduction in high-density lipoprotein (HDL). Most beta-blockers are associated with large increases in triglycerides and substantial reductions in HDL. Conversely, alpha 1-inhibitors, such as prazosin, doxazosin, and terazosin, lower total cholesterol, increases HDL, and favorably alter the HDL/total cholesterol ratio. Results of major clinical trials have demonstrated that lowering total cholesterol or low-density lipoprotein and increasing HDL reduces the risk of coronary heart disease. Therefore concerns have increased that the lipid effects of thiazides and some beta-blockers may totally or partly negate the beneficial reduction on coronary heart disease afforded by blood pressure reduction. Trial data can be used to estimate the potential secondary costs of disease outcomes that would be associated with lipid differences. Because there are presumably no secondary costs with alpha 1-inhibitors as a result of their favorable effects on lipids and because there are substantial secondary costs associated with thiazides, the cost of long-term treatment would be similar for the two agents.