Human orthostatic reflexes after taking temazepam at night

Area of Science:

• Pharmacology
• Cardiovascular Physiology
• Sleep Medicine

Background:

• Cardiovascular orthostatic reflexes are crucial for maintaining blood pressure.
• Temazepam is a benzodiazepine commonly used for insomnia.
• Understanding the impact of hypnotics on autonomic function is important for patient safety.

Purpose of the Study:

• To investigate the effects of temazepam on cardiovascular orthostatic reflexes.
• To assess the dose-dependent effects of temazepam on heart rate, blood pressure, and forearm blood flow.
• To determine the time course of temazepam's influence on autonomic responses.

Main Methods:

• A placebo-controlled, double-blind, cross-over study was conducted.
• 12 healthy male subjects received placebo or temazepam (10 or 20 mg) at night.
• Orthostatic reflexes were tested using lower body negative pressure (LBNP) at varying pressures (30, 40, 50 mm Hg).
• Measurements included heart rate, blood pressure, and forearm blood flow at baseline, 1.5, and 9.5 hours post-administration.

Main Results:

• Temazepam did not affect pre-suction resting values.
• 1.5 hours after 20 mg temazepam, subjects exhibited significantly greater tachycardia and reduced forearm vasoconstriction in response to LBNP compared to placebo.
• The effects of 10 mg temazepam were equivocal.
• No residual effects were observed the following morning.

Conclusions:

• Temazepam administration at night alters cardiovascular orthostatic reflexes, specifically increasing heart rate and decreasing vasoconstriction.
• These acute alterations did not compromise arterial blood pressure maintenance in healthy individuals.
• The findings suggest a transient impact of temazepam on autonomic cardiovascular control.