Related Experiment Video
Updated: Jul 7, 2026

Optogenetic Activation of Afferent Pathways in Brain Slices and Modulation of Responses by Volatile Anesthetics
Published on: July 23, 2020
[Sympathomimetic effects of low-dose S(+)-ketamine. Effect of propofol dosage]
Claudia Timm1, U Linstedt, T Weiss
1Klinik für Anaesthesiologie, Intensiv-, Palliativ- und Schmerzmedizin, Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil GmbH, Ruhr-Universität Bochum, Bürkle-de-la Camp Platz 1, 44789, Bochum. heinrichs@anaesthesia.de
Background:
In analgetic dosages ketamine has stimulatory effects on the cardiovascular system, which limits its use in patients with heart disease. The aim of this study was to clarify whether low-dose S(+)-ketamine used to prevent chronic pain similarly stimulates the cardiovascular system and to determine the impact of propofol dosage on this effect.
Methods:
A total of 80 patients undergoing surgery under spinal or epidural anesthesia were randomly assigned to receive double-blinded S(+)-ketamine [0.25 mg/kg body weight (BW) bolus followed by infusion of 0.06 mg/kg BW/h] or placebo in the presence of continuous propofol infusion (2-5 mg/kg BW/h). The heart rate, blood pressure and calculated rate-pressure product (RPP) were monitored.
Results:
Following the S(+)-ketamine bolus, the heart rate, blood pressure and RPP increased significantly. In the presence of a propofol dosage >3 mg/kg BW/h the stimulatory cardiovascular effect could no longer be observed.
Conclusion:
Even low-dose S(+)-ketamine has a stimulatory effect on the cardiovascular system. This stimulatory effect is nullified in the presence of a continuous propofol infusion at a dosage of more than 3 mg/kg BW/h.
Related Concept Videos
Parenteral Anesthetics: Overview
Skeletal Muscle Relaxants: Adverse Effects
Unlike...
Sedatives and Hypnotics Drugs: Miscellaneous Agents
Melatonin congeners like ramelteon (Rozerem) and tasimelteon (Hetlioz) selectively bind to melatonin receptors (MT1 and MT2) and thus mimic the actions of melatonin, a hormone that regulates sleep-wake cycles. Tasimelteon is primarily used for non-24-hour sleep-wake disorder, common in blind patients. They are also used to treat conditions like insomnia...
Stages of General Anesthesia
Depolarizing Blockers: Pharmocokinetics
Inhalational Anesthetics: Overview