The Effect of Pregabalin on the Minimum Alveolar Concentration of Sevoflurane: A Randomized, Placebo-Controlled, Double-Blind Clinical Trial

Abstract

Background: Pregabalin is commonly used perioperatively to reduce post-operative pain and opioid consumption and to prevent the development of chronic pain. It has been shown to reduce anesthetic consumption in balanced anesthesia, but studies investigating its effect on the minimum alveolar concentration (MAC) of volatile anesthetics are lacking. The aim of this study was to investigate the effect of two different doses of pregabalin on the MAC of sevoflurane.

Methods: In a randomized, double-blinded, placebo controlled clinical study, 75 patients were assigned to receive placebo, 300 mg pregabalin, or 150 mg pregabalin, as a capsule 1 h before anesthesia induction with sevoflurane only. After equilibration, the response to skin incision (movement vs. non-movement) was monitored. The MAC was assessed using an up- and down-titration method.

Results: The MAC of sevoflurane was estimated as 2.16% (95% CI, 2.07-2.32%) in the placebo group, 1.44% (95% CI, 1.26-1.70%) in the 300 mg pregabalin group, and 1.81% (95% CI, 1.49-2.13%) in the 150 mg pregabalin group. We therefore report a 33% reduction in the MAC of sevoflurane in the 300 mg pregabalin group as compared to placebo. The MAC of the 150 mg pregabalin group was reduced by 16% as compared to placebo but was not statistically significant.

Conclusions: The administration of 300 mg pregabalin reduced the MAC of sevoflurane by 33%, while the administration of 150 mg pregabalin did not significantly reduce the MAC of sevoflurane. Pregabalin use led to a small reduction in post-operative pain levels but increased side effects in a dose-dependent manner.

Keywords: anesthesia; depth of anesthesia; minimum alveolar concentration (MAC); pregabalin; premedication before anesthesia; sevoflurane.

Figure 1

CONSORT flow diagram. CONSORT, Consolidated standards of reporting trials. ^aReasons for exclusion: 4 patients received sedative premedication. ^bReasons for not receiving allocated intervention: 3 patients developed mild laryngospasm at induction that required intravenous anesthetics.

Figure 2

Titration process in the study groups. Circles indicate patients who moved, and rhombi indicate patients who did not move. Solid horizontal lines indicate the bootstrap estimates for the MAC, dashed horizontal lines indicate the 95% confidence intervals. MAC, minimum alveolar concentration.