Key result
Propranolol added to minoxidil decreased heart rate in proportion to log plasma concentration, while maximum reduction in plasma renin activity occurred at lower concentrations.
Why the study?
Does the addition of propranolol to minoxidil reduce minoxidil-induced increases in heart rate and plasma renin activity in patients with essential hypertension?
Does the addition of propranolol to minoxidil reduce minoxidil-induced increases in heart rate and plasma renin activity in patients with essential hypertension?
Maximum antagonism of adrenergically mediated increases in plasma renin activity is produced by much lower concentrations of propranolol than maximum suppression of adrenergically mediated increases in heart rate.
Answers are grounded in this paper and cite their sources.
Lower propranolol concentrations may suffice for renin suppression than heart rate control with minoxidil; leaves open dose optimization in essential hypertension.
The relationship between PPC and its effect on minoxidil‐induced increases in PHA and heart rate was examined in 9 patients with essential hypertension. Concomitant with the minoxidil‐induced depression of mean arterial pressure (30.7 ± 3.5 mm Hg, mean ± SEM), heart rate increased from 79.1 ± 3.0 to 100.4 ± 4.6 BPM, and PHA increased from 1.12 ± 0.28 to 8.58 ± 2.83 nglmllhr. Addition of propranolol to minoxidil caused a decrease in heart rate in proportion to log PPC: Δ heart rate = 1.1 − 12.8 log PPC (r, 0.59, p < 0.005) The relationship between PPC and the reduction in PHA was more complex. While a major reduction in PHA was observed at PPC in the range 20 to 60 nglmllhr, there was no consistent effect on PHA at higher PPC. Therefore, maximum antagonism of adrenergicaUy mediated increases in PHA is produced by much lower concentrations of propranolol than maximum suppression of adrenergically mediated increases in heart rate.
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Velasco et al. (1974) studied Essential hypertension (n=9). Propranolol vs. Minoxidil alone was evaluated on Heart rate and plasma renin activity (PHA) (r=0.59, p=<0.005). Propranolol added to minoxidil decreased heart rate in proportion to log plasma concentration, while maximum reduction in plasma renin activity occurred at lower concentrations.
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