Hypertension is a major risk factor for cardiovascular disease, particularly in combination with other factors such as obesity, smoking, diabetes and dyslipidemia. Effective management of hypertension results in reduced morbidity and mortality. The latest report from the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) recommended the use of diuretics or beta blockers as initial therapy for uncomplicated hypertension unless there are specific indications for the use of another drug. This recommendation is based on evidence from 17 long-term, controlled trials in which these agents reduced morbidity and mortality from cerebro- and cardiovascular disease. Despite these recommendations, many clinicians are hesitant to prescribe these two medications as initial therapy. Some physicians have expressed concern about the potential adverse effects on lipids. Weir and Moser summarized results from numerous clinical trials to assess the potential impact of these medications on the serum lipid profile.
After evaluating many of the studies of long-term treatment with thiazide diuretics, they noticed that a modest elevation in serum cholesterol may occur during the first year, but it subsides back to or below baseline values after this time. The effect appears dose-related, with higher dosages of thiazides (more than 50 mg per day) increasing total cholesterol by 4 percent. With lower dosages of thiazides (25 to 50 mg per day), the differences in serum cholesterol are small and of questionable clinical significance. In reviewing the use of beta blockers, it was found that nonselective beta blockers may decrease high-density lipoprotein cholesterol levels by 10 to 20 percent or increase triglyceride levels 20 to 50 percent. Cardioselective beta blockers (e.g., atenolol and metaprolol) have a lesser effect on serum cholesterol.
The results of this review demonstrated that low dosages of thiazide diuretics or cardioselective beta blockers alone or in combination result in minimal changes in the lipid profile. The authors conclude that there is little or no evidence that the minimal changes in serum lipid profile associated with the use of these drugs result in negating the beneficial effects of the agents on blood pressure.