Nebulized Magnesium Sulfate and Sildenafil for Persistent Pulmonary Hypertension of Newborn

This trial is testing two treatments — nebulized magnesium sulfate (inhaled through a breathing mask) and sildenafil (commonly known as Viagra, but used here to relax blood vessels in the lungs) — for newborns with persistent pulmonary hypertension (PPHN), a serious condition where blood pressure in the lungs is dangerously high. **You may be eligible if...** - Your baby is at least 36 weeks gestational age - Your baby weighs between 2.5 and 4 kg at birth - Your baby is between 6 and 72 hours old - Your baby has been diagnosed with PPHN confirmed by heart ultrasound (echocardiography) - Your baby has a high oxygen index (OI >30 on two readings) and is on a ventilator **You may NOT be eligible if...** - The mother received magnesium sulfate within 48 hours before delivery - Your baby has a congenital heart defect (other than patent ductus arteriosus or patent foramen ovale) - Your baby has a major birth defect (like a diaphragmatic hernia) - Your baby has needed resuscitation at birth - Your baby has very low blood pressure not responding to medications - Your baby has kidney problems or GI bleeding - Your baby has previously received drugs to lower lung blood pressure Talk to your doctor to see if this trial is right for you.