June 26, 2001

Dexamethasone is a cost-effective alternative to ondansetron in preventing PONV after paediatric strabismus repair.
Subramaniam B, Madan R, Sadhasivam S, et al. Br J Anaesth 86:84-89, 2001

Commentary by Kathryn McGoldrick, M.D.

In children, strabismus repair is associated with a high incidence of PONV, which ranges from 41 to 88% in those who have not received antiemetic prophylaxis. [1,2] (Historically the basal incidence of PONV was 80% at institutions of the authors of this paper). Several studies have shown that ondansetron is effective in the prevention of PONV after strabismus surgery [3-6], but a meta-analysis [7] has challenged the clinical utility of prophylactic ondansetron in preventing PONV on the basis of its efficacy and side-effects (headache, liver function abnormalities). Moreover, the relatively high cost of ondansetron causes concern.

Dexamethasone has been shown to be an effective antiemetic in children undergoing ambulatory adenotonsillectomy [8.9]. Although the mechanisms of its antiemetic effects have yet to be clearly established, dexamethasone may act via prostaglandin antagonism[10], serotonin inhibition in the gut [11], and by endorphin release [12].

This prospective, randomized, placebo-controlled, double-blinded study convincingly demonstrated that the incidence of PONV was significantly greater in the placebo group than in the ondansetron (P=0.0001) and dexamethasone groups (P<0.0001). The incidence of early PONV (0-6 hr) was significantly lower in the ondansetron and dexamethasone groups than in the placebo group. The incidence of PONV in the late postoperative period (6-24 hr) was significantly lower in the dexamethasone group (6.67%) than in the ondansetron (24.4%; P=0.04) and placebo groups (31.1%; P=0.003). Indeed, the incidence of late PONV was comparable in the ondansetron and placebo groups (P=0.48). Moreover, the severity of late PONV was markedly less in the dexamethasone group than in the ondansetron group.

The prolonged antiemetic efficacy of dexamethasone is not surprising given its biological half-life of 36-72 hr. Of interest, however, was the finding that the requirement for postoperative analgesic supplements was notably lower in the dexamethasone group. This is consistent with an earlier investigation showing that betamethasone prophylaxis decreased postoperative pain and late PONV in ambulatory surgical patients [13].

Finally, it should be noted that the sample size of the current study was inadequate to identify an adverse effect with an incidence of less than 2.2 percent. However, a recent meta-analysis of dexamethasone and PONV did not disclose any notable side effects [14]. As yet, I am unaware of any evidence in the literature of dexamethasone’s potential side-effects, such as delayed wound healing and hypothalamic-pituitary-adrenal axis suppression, occurring after single dose administration.

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14. Henzi I, Walder B, Tramer MR. Dexamethasone for the prevention of postoperative nausea and vomiting: a quantitative systematic review. Anesth Analg 2000; 90:186-94.
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Dexamethasone is a cost-effective alternative to ondansetron in preventing PONV after paediatric strabismus repair

AUTHORS:
Subramaniam B, Madan R, Sadhasivam S, et al.

SOURCE:
Br J Anaesth 86:84-89, 2001

ABSTRACT:
No abstract available