IbuprofenAnti-Inflammatory Agents, Non-SteroidalAnalgesics, Non-NarcoticAcetaminophenCyclooxygenase InhibitorsNaproxenDiclofenacAntipyreticsDuctus Arteriosus, PatentDouble-Blind MethodKetoprofenTherapeutic EquivalencyAdministration, OralTreatment OutcomeCyclooxygenase 2 InhibitorsDose-Response Relationship, Drug