Have been sitting on this reply since the day the site crashed. So here it is - better late than never....
Now I know the title of this thread includes "a possibility other than reflux" but I do want to point out a couple of things related to reflux.
Reflux babies notoriously eat better when they are sleepy. They don't seem to be as aware of their surroundings and consequently don't make the connection between feeding and pain that they do when they are awake. Once they are taking more at night than during the day it is termed reverse cycling. My DS2 took up to 75% of his intake during the night and when he was just awake until I got his reflux under control with medications and then gave him time to unlearn the association.
sleepyhummel - Firstly a huge pile of (((Hugs))). This is a horrible time for you and I wish I could say or do something to make it better. I do want to give you some suggestions that I hope will help you.
Firstly if your DS is still on Zantac it sounds like he has developed a tolerance to it (very common in LO's) and needs to be on different medication. There is another group of medications called Proton Pump Inhibitors that work in a different manner than Zantac but the end result is the same. The common ones that I've seen used in LO's are Omeprazole and Lansoprazole. The chances of tolerance developing in LOs on a PPI are very small.
He may also benefit from a medication to speed the progress of food through his stomach so it isn't there long enough to come back up. The 2 most commonly used ones are Domperidone and Metoclopramide.
If the LO has latching/sucking issues then please, please, please get them assessed for tongue-tie. I know it is mentioned earlier in the thread. I also know that the general thought is that a bottle fed LO shouldn't be affected by a tongue-tie. This isn't always the case. And if the tongue-tie is located in such a place that the LO cannot co-ordinate their sucking and swallowing, then it stands to reason that they would choke on their food. I wonder if this was the original issue for you Wendy, and if it still is.
I'm no expert on formulas. But from the mothers on the Reflux board and from doing some researching on-line about them, this is what I found. I borrowed this info from this website http://foodallergies.about.com/od/adultfoodallergies/p/hypoallergenic.htm
as it is worded very well and seems pretty easy to understand.
Hypoallergenic formulas come in three main varieties: partially hydrolyzed, extensively hydrolyzed, and free amino acid-based. Hydrolyzed formulas have had the larger protein chains broken down into shorter, easy-to-digest proteins, while free amino acid-based formulas do not include protein chains at all but rather contain all the basic amino acids. Partially hydrolyzed formulas differ from extensively hydrolyzed formulas in that their protein chains can be longer. Alimentum, Nutramigen, and Pregestimil are among brands of hydrolyzed formulas, while Neocate, Elecare, and Nutramigen AA are amino acid formulas.
If your LO has a particularly sensitive stomach and intestines then maybe the partially or extensively hydrolyzed formulas are still exposing them to enough cows milk proteins that they are reacting. I know the amino acid formulas are sometimes only available by prescription and that they are expensive. But if it's that bad, IMHO cost becomes irrelevant.
If your LO has a milk protein intolerance, they may also have a condition known as eosinophilic esophagitis. This condition is "resistant" to all reflux drugs. These two pages have information about this condition http://www.allergycapital.com.au/Pages/Eosin_Esophagitis.htmlhttp://www.apfed.org/downloads/EE_Information.pdf
And one of our 'seasoned' reflux mothers has a DS who has eosinophilic colitis. Her story is on this page http://www.babywhispererforums.com/index.php?topic=107244.0
In terms of the blase attitude and the "he isn't the biggest of babies but he isn't failure to thrive yet" comment, it makes my blood boil. It is totally unacceptable to wait until a child is in the catagory of failure to start to 'panic'. Once they reach that stage it is a hard work to get them to eat etc as they have usually developed severe food intolerances/aversions etc. Keep going back to the doctors. I would even change doctors if you can and especially if you don't feel that this particular one is listening to your concerns and taking you seriously.
Ok. This was supposed to be a short note and is now an epistle. Hopefully there is something here that helps someone.