Clinical evidence for drug treatments in obesity-associated hypertensive patients--a discussion paper.

The association between obesity and hypertension is well known. The hemodynamic features of obesity-related hypertension are an expansion of extracellular volume inducing hypervolaemia and increased cardiac output, with activation of both the sympathetic nervous system and the renin--angiotensin system. It is suggested that obesity-related hypertension may be considered as a subset of essential hypertension, and treated as an identity. Orlistat and sibutramine both reduce body weight in the obese patients. The use of orlistat in obese hypertensive patients is associated with a small decrease in blood pressure, whereas sibutramine may increase the blood pressure. Thus, orlistat may be preferred in the obese hypertensive patients. Diuretics and beta-blockers decrease insulin sensitivity, which is an unwanted effect in obesity, and should be used with caution in obese hypertensive patients. The calcium channel blockers have no or minor effects on insulin sensitivity and may be considered for use in obese hypertensive patients. Inhibitors of the effects of angiotensin may be the antihypertensive drugs of choice for obese hypertensive patients, as in addition to reducing blood pressure, ACE inhibitors and AT(1) receptor antagonists have no effect or improve insulin sensitivity, and are renoprotective. More clinical trials are needed for the centrally acting antihypertensives (clonidine, rilmenidine) in obese hypertensive patients, as they inhibit the sympathetic nervous and renin--angiotensin systems, which are overactive in this population.