Use of Tapentadol Oral Solution for Pain After Surgery in Children From Newborn to Less Than 2 Years Old

This is a multicenter, open-label (all people involved know the identity of the intervention), single dose trial to evaluate the pharmacokinetic (PK) profile (how drugs are absorbed in the body, how are they distributed within the body and how are they removed from the body over time) in children aged from birth to less than 2 years after a surgical procedure that routinely produces moderate to severe acute post-surgical pain. The trial will also evaluate the safety and tolerability of tapentadol oral solution in the population studied and the effect of tapentadol oral solution on pain.