Similar to what Mofe'ny found, I found this tidbit in my Neonatal Medications & Nutrition: A Comprehensive Guide, 3rd Edition by Zenk, Sills, & Koeppel on page 323 where it speaks to Administration of Indomethacin (Indocin IV):
"Although the manufacturer recommends infusion over 5-10 seconds, rapid administration may cause significant decrease in mesenteric artery and cerebral blood flow, which may contribute to development of NEC or cerebral ischemia. Hammerman and associates found that slow, continuous infusion at 11 mcg/kg/hour for 36 hours (=396 mcg/kg) was effective in closing the ductus and minimized the potential adverse effects of reduction in cerebral blood flow velocity and increase in serum creatinine, compared with an equivalent dose of 0.2 mg/kg, then 0.1 mg/kg, 0.1 mg/kg every 12 hours IV, by rapid 1-minute injection for 2 additional doses (=400 mcg/kg). Further study is needed, however, because this study had a small number of patients."
References for this information include:
Coombs RC, et al. 1990. Gut blood flow velocities in the newborn: Effects of patent ductus arteriosus and parenteral indomethacin. Archives of Disease in Childhood 65(10 spec.no.): 1067-1071.
Hammerman C, et al. 1995. Continuous versus multiple rapid infusions of indomethacin: Effects on cerebral blood flow velocity. Pediatrics 95(2): 244-248.
All in all, it seems like a good idea to give it slower if it works to close the PDA, yet doesn't have such detrimental effects on babies brain development and intestinal health... Don't we just love research that helps us take care of babies better? I wonder if any other studies have been done which correlate with the one Hammerman, et al. did.....