(934) Guanfacine Compared to Clonidine for Discontinuing Dexmedetomidine Infusions

Introduction: Continuous dexmedetomidine infusions longer than 72 hours carry risk for symptomatic withdrawal upon discontinuation. Both clonidine and guanfacine have been studied to aid in dexmedetomidine discontinuation. Like dexmedetomidine, clonidine is non-selective for alpha-2 subtypes and imidazoline receptors, theoretically increasing the risk for hypotension. Guanfacine is a selective alpha-2a agonist that works centrally and may provide a more favorable side effect profile. The aim of this study was to evaluate the efficacy and safety of guanfacine compared to clonidine for discontinuing long-term dexmedetomidine infusions.

Methods: This multi-center, retrospective, cohort study evaluated adult patients who received continuous infusion dexmedetomidine for 72 hours or longer prior to enteral alpha-2 agonist initiation. The primary outcome was response to guanfacine or clonidine within 24 hours. Secondary outcomes included intensive care unit (ICU) length of stay, total duration of dexmedetomidine infusion, and addition or dose increase of concurrent psychoactive medications during the wean period.

Results: Seventy-nine patients were included in the final analysis. Mean age was 50 years, 57 (72.2%) were male, and 49 (62%) of patients were on dexmedetomidine for more than 168 hours prior to the first dose of guanfacine or clonidine. Clinical response at 24 hours was seen in 7 (25%) of guanfacine group compared to 20 (39.2%) with clonidine (p=0.2). Within the 72 hours monitored, 16 (57.2%) responded to guanfacine and 33 (64.7%) responded to clonidine (p=0.5). ICU length of stay was similar between groups. Hypotension and bradycardia occurred in 17 (60.7%) and 1 (3.6%) of patients with guanfacine and 25 (9.8%) and 5 (9.8%) with clonidine.

Conclusions: In patients on continuous dexmedetomidine infusions for longer than 72 hours, both clonidine and guanfacine may be effective oral agents to aid in dexmedetomidine discontinuation. Prospective studies in this area are warranted to further assess efficacy, safety, and cost-effectiveness.