Journal of cardiovascular pharmacology
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J. Cardiovasc. Pharmacol. · Aug 1998
Randomized Controlled Trial Clinical TrialNoninvasive indices of autonomic regulation after alprazolam and lorazepam: effects on sympathovagal balance.
Skin conductance level (SCL) and spectral analysis of variations in heart rate (HR) and blood pressure (BP), in relation to plasma catecholamine concentrations, were used to evaluate autonomic nervous system activity during situations of supine rest within a period of 4 h after oral administration of 1 mg alprazolam and 2 mg lorazepam. Twelve healthy men received in a double-blind, randomized crossover design, either 1 mg alprazolam, or 2 mg lorazepam, or a placebo on different days. ECG, BP, respiration, and SCL were monitored continuously during each session. ⋯ Alprazolam and lorazepam had no effect on respiratory frequency. Noninvasive indices of autonomic regulation revealed several small, but significant, time-dependent effects of 1 mg alprazolam on sympathetic and parasympathetic processes, whereas for 2 mg lorazepam, these effects were less clear. The reduction in noninvasive indices of sympathetic tone after alprazolam administration corresponded with the attenuation of plasma noradrenaline concentrations by alprazolam.