Background: Postoperative sore throat (POST) is an undesirable complaint after orotracheal intubation. Magnesium is a noncompetitive N-methyl-D-aspartate receptor antagonist thought to be involved in the modulation of pain. The present study aimed to investigate the effect of preoperative administration of oral magnesium lozenge on POST.
Methods: Seventy patients undergoing orthopedic surgery were randomly allocated into two groups, to either receive placebo (control) or magnesium lozenges (magnesium) to be dissolved by sucking 30 min preoperatively. Patients were assessed for incidence and severity (four-point scale, 0-3) of POST at 0, 2, 4, and 24 h postoperatively. The primary outcome was sore throat at 4 h after surgery. The secondary outcome was the severity of POST at four evaluation time-points postoperatively.
Results: The incidence of POST at 4 h was higher in control group than in magnesium group (95% CI: 26%, 14-42%; P=0.032). The highest incidence of POST occurred at the second hour after surgery, with the rate of 23% in the magnesium group and 57% in the control group (95% CI: 34%, 20-51%; P=0.007). The severity of POST was significantly lower in the magnesium group at 0 (P=0.007) and 2 h (P=0.002). The incidences of POST at 0 and 24 h and severity scores at 4 and 24 h were not significantly different between the groups.
Conclusions: The administration of magnesium lozenge 30 min preoperatively is effective to reduce both incidence and severity of POST in the immediate postoperative period.