For that weight I get .6ml to 1.2ml three times a day, so if you aren't seeing any improvement, then ask your dr if you can go higher. They have a book that they use to work out the doseage, there is a minimum and maximum, even if he is on the maximum it won't hurt him, zantac is a really safe drug that has been around for a long time.

I would find when Parker was on zantac that it would work great for a week and then things would go bad. The doctor showed me how to work out the dose so I could adjust it with weight gain and it worked better if we increased it with his weight.

If after trying the increase for say a couple of days to a week, then go back to the losec, if you are on a good dose and it isn't working I would just move on. PPI's like losec are safe too but work differently. Just remember that they can take up to two weeks to see a difference sometimes longer to see the true effect since it depends on how much healing has to be done