Anesth 2001; 94(3):385-9

Reviewed by: R. Prasad, MD

Summary:

• Loading dose 40mg/kg FeverAll suppositories followed by 20mg/kg q6h (all rectal) results in serum concentration 10-20 mcg/ml (which has been reported to be antipyretic, and probably also provides analgesia).

• Important info since so many of our outpatient kids get rectal Tylenol
• Don't forget to tell parents when it's OK to give the next dose!

• 16 kids, age 2-12yr for elective ortho surgery
• ASA 1-3, Hct > 30%
• Venous blood q30min x 4h, then q60min x 6h, then q4h x 16h
• Used FeverAll suppositories
• Determined the fraction of time that each pt maintained "therapeutic" level (10-20 mcg.ml) from initial dose until 6h after last dose given.
• Also, tested if their model (to predict serum levels) was accurate.

• All initial doses within 6% desired (used various combinations of rectal doses)
• Incomplete sampling due to pt discharges, loss of IV, etc.
• 6 pts only got initial bolus: serum levels in target range 38 +/- 25% of the time.
• 10 pts got >1 dose: in target range 60 +/- 29% of the time.

• Initial absorption highly variable - explains low % in target range initially.
• Serum levels >20 mcg/ml in 5 pts, but peak always <40. Hepatotoxicity risk low - generally not seen at concentrations < 120 mcg/ml.
• Data somewhat different from other studies - may be due to formulation used (different ones have different bioavailability)
• Desired target range of 10-20 mcg/ml is probably analgesic, but not entirely clear.
• Results may not apply outside 3-12yo range (esp premies, neonates who may have different clearance)