I have managed to get my DD out of silent reflux so would like to share with you how it worked.
As a reminder, silent reflux is when acid generated by the digestion of the milk goes up and down the throatpipe because the stomach does not close properly, but the baby does not vomit all the milk (that would be fullblown reflux). Reflux subsides when the baby is able to sit and then stand, thanks to the vertical position and having more strength in the chest area.
From 3 weeks old DD would scream in pain for about 45 minutes, two hours after her last bottle. That would happen only during the day, once after her 11am bottle (so around 1pm) and once after her 3pm bottle (so around 5pm). She would also do a lot of spits I would give her the breast thinking she was hungry and that would soothe her, but the pediatrician explained to me that it was because the milk would act as a lining to her throatpipe, but later of course compound the problem. Her weight gain was great (following the median line, which is exceptional for a breastfed baby), and she would sleep well at night.
I had to carry her on my shoulder for 2 hours each day enduring her crying and screaming in pain not being able to do anything about it, and almost had a nervous breakdown.
First she was given infant gaviscon. That definitely helps reduce spits because the milk becomes heavier and tends to stay more in the stomach. But it is useless in curing infant reflux, all the symptoms continued. DD is now 7 months old and I've been able to stop Gaviscon, she does not need it anymore, the milk stays down and there have been no more spits for quite a while.
We then tried Ranitidine: it helped a bit at first, on and off, but then the symptoms came back. I found the effects of this medicine were quite unpredictable and not reliable.
Then after 4 months of reflux, being French, I discussed it with friends who have children in Paris who had silent reflux as babies, and over there pediatricians immediately prescribe omeprazole (Mopral; in England it's called Losec) for silent refluxers. So we started Losec (omeprazole) and also Domperidone. After a few days Losec really started to kick in and the crying completely disappeared. SHE HAS NOT HAD SILENT REFLUX ever since taking 10mg Losec.
There are a couple of tricks to make it work:
(1) at first the pediatrician told us to give it in the evening. It would not be fully effective that way because her silent reflux happened from 1pm. So I took the initiative of giving it in the morning (first thing when she woke up) and that worked PERFECTLY WELL, she had no more reflux at all. She has not had any side effects whatsoever.
(2) It is better to buy the capsules, then you open them in two and put the little granules in a bit of fruit puree in a spoon. When DD was not diversified I put it in a gel similar to Dentinox or Infacol, in a spoon. Then I would give her 2.5mls of water with a small syringe, to wash it down. At first we tried to dissolve tablets of omeprazole to give a lower dose: that was not effective, and very difficult to administer the dissolved granules. Also, you need to give a big dose (she's been on 10mg almost from the start, at 4 months) for it to work well.
(3) Domperidone: at first I found it helpful because it would definitely reduce her spitting, but after a few weeks she did not need it anymore. You have to give it between 15mn and 30mn before her feed. Strongly recommend you buy the small 2.5ml syringes at pharmacies rather than use the ones the pharmacy gives you, which are too big for the baby's mouth.
Things that don't work: it helps a bit to put a towel under your baby's mattress where her head is, to make a gentle slope, but keeping your baby in a seat or other upright position is very bad for her skeleton, and also for her oxygenation, and does not help with reflux.
Hope this helps.