1 In a single blind study seventeen patients with mild or moderate essential hypertension and normal renal function were treated with labetalol alone in increasing doses from 300 via 600 to 1200 mg daily. 2 Average supine BP (systolic/diastolic) was reduced by 24/19 mm Hg. Seven patients attained a diastolic BP less than or equal to Hg. A significant postural fall in systolic BP was recorded, but no symptomatic orthostatic hypotension occurred. 3 In twelve patients measurements of plasma volume (125I‐albumin), extracellular volume (82Br‐space) and glomerular filtration rate (51Cr‐EDTA clearance) on placebo and subsequently labetalol showed no systemic changes. 4 Side effects were few causing two withdrawals because of impotence and arthralgia. 5 It is concluded that monotherapy with labetalol results in clinically relevant, persistent and dose dependent reduction in BP in patients with mild or moderate essential hypertension, apparently without concomitant expansion of body fluid volumes or influence on glomerular filtration rate.
ABSTRACT. Changes in blood pressure, plasma volume (PV) (125I‐albumin space), extracellular volume (ECV) (82Br‐space) and glomerular filtration rate (GFR) (51Cr‐EDTA clearance) were measured in 12 patients with mild to moderate essential hypertension on placebo and during long‐term treatment with prazosin. During the study, BP decreased from an average of 172/107 to 166/102 mmHg (n.s.). PV increased from 3278 to 3324 ml (n.s.) and ECV from 18360 to 18639 ml (n.s.). GFR was almost unchanged, 95 and 93 ml/min, prespectively. An inverse significant correlation was found between the changes in mean BP and changes in ECV, i.e. fluid retention was demonstrated in patients with the smallest BP reduction. It is concluded that inadequate BP response during treatment with prazosin may in part be due to fluid retention. It is therefore suggested that prazosin should in principle be used together with a diuretic in order to prevent fluid retention.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.