Background Due to haemorrhagic risks, ibuprofen lysine may have advantages over indomethacin, when used to effect closure of a neonate’s patent ductus arteriosus (PDA). Platelet plug formation is impaired after the administration of indomethacin, but it is unclear whether this occurs with ibuprofen.

Methods We performed template bleeding times and platelet function analyser (PFA)-100 tests on 20 neonates at intervals before and after ibuprofen. Bleeding times were done per our previous reports, using the Surgicutt Newborn (International Technidyne). Our haematology laboratory performed the PFA-100 tests (Dade Schering).

Results Patients ranged from 23 to 40 weeks gestation and weighed 511–2566 g. The first dose of ibuprofen was administered at 72 (18–363) h after birth (median, range). No bleeding problems were noted during ibuprofen dosing. Bleeding times before dosing ranged from 135 to 450 s. Repeat tests were done in groups of four, at 2, 4–6, 12–18, 24 h after the first dose and 2 h after the third dose of ibuprofen. No change in bleeding times was detected (p = 0.299). The 10 patients weighing <1000 g tended to have a shortened bleeding time (mean of 20 s shorter), whereas the 10 weighing >1000 g tended to have a prolongation in bleeding time (mean of 41 s longer). Before ibuprofen, PFA-100 times ranged from 52 to 300 s. A paired t test showed slight but statistically significant lengthening in PFA-100 time after the ibuprofen administration (p = 0.019).

Conclusions We found ibuprofen lysine administered to neonates with a PDA according to the manufacturer’s recommendations has little adverse effect on platelet plug formation and might be a factor when choosing between indomethacin and ibuprofen.