Effectiveness of oral vs rectal acetaminophen: a meta-analysis

To determine, on the basis of published studies, the efficacy of rectal vs oral acetaminophen as treatment of fever and pain.

MEDLINE, PubMed, and the Cochrane database as well as major pharmacologic textbooks and the references of all included studies were searched for studies comparing oral and rectal administration of acetaminophen.

Randomized and quasi-randomized controlled studies comparing rectal and oral administration of acetaminophen were included. Reviews, letters, and studies that compared combined treatments or additional drugs were excluded. Main Exposure Oral vs rectal acetaminophen.

Standardized measures of temperature and pain reduction.

For temperature reduction, 4 studies met the inclusion criteria. The decline in temperature 1 hour after administration of acetaminophen was no different between rectal and oral administration (weighted mean difference [WMD], -0.14 degrees C; 95% confidence interval [CI], -0.36 degrees C to 0.08 degrees C; P for heterogeneity = .49). There was no difference in the decline of temperature 3 hours after administration (WMD, -0.10 degrees C; 95% CI, -0.41 degrees C to 0.21 degrees C; P = .84), the maximum decline in temperature (WMD, -0.10 degrees C; 95% CI, -0.24 degrees C to 0.04 degrees C; P > .99), or the average time to temperature reduction of 1 degrees C (WMD, -0.06 degrees C; 95% CI, -1.34 degrees C to 1.23 degrees C; P < .001). We did not perform a meta-analysis comparing rectal and oral acetaminophen for pain reduction because only 1 study fulfilled the inclusion criteria.

Rectal and oral acetaminophen are comparable with respect to temperature reduction. The American Academy of Pediatrics recommendation to refrain from rectal acetaminophen in children should possibly be revised.