[Hypotensive agents].

Carvedilol (Kredex, Coreg) is a multiple action antihypertensive drug that has been shown to protect cell membranes from lipid peroxidative damages. In this study the physical and structural effects of carvedilol on lipid bilayers are investigated by fluorescence techniques, differential scanning calorimetry and other physical methods. Carvedilol binds to liposomal membranes (9:1 DMPC:DMPG) strongly with an apparent binding constant on the order of 10(4) M-1 in PBS (pH 7.4). The characteristic changes in its intrinsic fluorescence properties when bound to liposomes suggest that this compound is situated in a non-polar environment. The Stern-Volmer and bimolecular quenching constants, determined using nitrate as the fluorescence quencher, for the free and bound carvedilol indicate that the carbazole moiety is at a depth of > 11 A in the lipid bilayer. Fluorescence anisotropy measurements show that, unlike the membrane probes DPH and TMA-DPH, carvedilol is relatively mobile, and does not have a rigidly-defined molecular orientation in the bilayers. Differential scanning calorimetry results indicate that carvedilol is an effective membrane "fluidizer' as it dose-dependently lowers the gel to liquid crystalline transition temperature and broadens the endothermic transition. Comparative studies of interactions of carbazole, 4-OH carbazole and carvedilol with the model liposomal membranes reveal a possible role of membrane-partitioning in their antioxidant efficacy. These findings are discussed in perspective with the membrane biophysical properties of different classes of therapeutic significant lipid antioxidants in mind.

Antihypertensive Agents↗

PubMed1996

The impact of ethnicity on response to antihypertensive therapy.

The aim of this review is to assess the prevalence of complications and responses to various antihypertensive drug therapies in ethnic minority groups in the United States. In some instances, these comments are extended to responses of citizens in their countries of origin. The incidence of hypertension, mortality from hypertensive heart disease, stroke, and hypertensive renal disease are higher in African Americans. Although some Hispanic Americans have a lesser risk for hypertension, they have a greater risk for other risk factors such as diabetes and dyslipidemia. There is a similar association between income and mortality for both African Americans and Hispanic Americans. When compared to European Americans and other ethnic minorities, African Americans respond less favorably to beta blockers and angiotensin-converting enzyme (ACE) inhibitors. Nevertheless, the observed response in African Americans to ACE inhibitors and beta blockers is clinically significant. The available literature indicates that Asian American responses to calcium antagonists seem to be more favorable than responses to ACE inhibitors and equivalent to their responses to diuretic and beta blocker therapy. Although there are few published studies of drug efficacy in Hispanic Americans, there appears to be no hierarchy in response to the various antihypertensive drug classes. Ethnicity is not an accurate criterion for predicting poor response to any class of antihypertensive therapy. Thus, there is little justification to use racial profiling as a criterion for the avoidance of selected drug classes because of presumed lack of efficacy. Observed differences in the incidence of hypertension and its poor outcomes have led some investigators to postulate that the etiology of hypertension in ethnic minority groups is intrinsically different from whites. Awareness of racial differences in hypertension outcomes evolved in the United States within a historical context that does not fully appreciate that race is often a surrogate for many social and economic factors that influence health status and healthcare delivery. Poor outcomes in ethnic minority groups occur in many diseases, not only hypertension. The goal of ethnicity-related research should be to describe the diversity of disease expression in humans and to target at-risk groups for prevention and early intervention. The use of racial descriptors to explain genetic differences in ethnic groups should take a lesser priority.

Antihypertensive Agents↗