Comparison of intraosseous versus intravenous loading of phenytoin in pigs and effect on bone marrow.

Much recent literature supports the resurgence of the intraosseous route of access in pediatrics. Intraosseous lines provide a timely noncollapsable route to the circulation in medical or traumatic emergencies when intravenous access is not possible. There has been no controlled study comparing intravenous and intraosseous loading of phenytoin. A 15 mg/kg dose of phenytoin was administered over 15 minutes to pigs by either the intravenous (n = 6) or tibial intraosseous route (n = 6). Femoral artery blood samples were drawn every 5 minutes for 35 minutes after initiation of infusion to determine phenytoin levels. There was no statistical difference between the two groups using analysis of variance repeated measures (P = .160). Microscopic examination of the cortex and marrow at the intraosseous site in these pigs was normal 5 weeks postinfusion. The authors conclude that the intraosseous route is an effective alternative to intravenous loading of phenytoin without permanent damage to the marrow.