Journal of clinical pharmacy and therapeutics
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of the beta1-selectivity of three beta1-selective beta-blockers.
To determine the relative beta1-selectivity of three beta-blockers (nebivolol, bisoprolol and atenolol), administered orally at normal therapeutic doses, by assessing their impact on the beta2-mediated, haemodynamic and biochemical responses to a terbutaline infusion, which decreases serum potassium and increases serum glucose and insulin. ⋯ The beta1-selectivity of three different beta1-blockers has been demonstrated in healthy volunteers using the blocking of biochemical and haemodynamic responses to a beta2 stimulus. Terbutaline alone caused an increase in heart rate, a rise in systolic blood pressure, a fall in serum potassium and a rise in both serum glucose and insulin. In this study, for both haemodynamic and biochemical responses, atenolol 100 mg had the greatest beta2-blocking effect, nebivolol 5 mg the least. Bisoprolol 10 mg and atenolol 50 mg had intermediate effects; bisoprolol was the more beta1-selective of these two.
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Salbutamol is commonly delivered as a racemic mixture of pharmacologically active (R)-salbutamol and inactive (S)-salbutamol. This study investigated inactive (S)- and active (R)-salbutamol plasma levels and their relationship to dose in patients with severe asthma. ⋯ Only a small fraction of total plasma salbutamol concentration was found to consist of active enantiomer in patients with an acute severe exacerbation of asthma actively undergoing treatment with racemic-salbutamol. As a result of the possible contribution of (S)-salbutamol to poor asthma control further enantioselective investigations are warranted in severe asthma.