My 11 month old has had reflux since she was born. It was finally diagnosed at four months, and we started Zantac. It really helped a lot with her pain--the constant screaming subsided substantially, but she continued to spit up. At her nine-month well check, she had flattened out on her growth chart for both height and weight. She had an upper GI study done, and the only abnormality found was the reflux. I believe she was just not keeping enough food down. The more we fed her, the more she spit up.
We then started Prilosec, and it has been wonderful. She is not in any pain or discomfort AND the spitting has all but subsided. She may spit a tiny bit every few days or so, but nothing like before. I would certainly give the Zantac a try and see how it works for you. Just keep an eye on the frequency/amount of spit up and your child's growth.
Things that help--keeping the baby upright for 1/2 hour or so after eating, sleeping on an incline, swaddling (the pressure on the belly helps). We found the Miracle Blanket to be really helpful--it is the only thing that put our daughter to sleep (www.miracleblanket.com). Please feel free to contact me with any questions. I've been through a tough first year with a reflux/milk allergy baby, and I've lived to tell about it! I'm always willing to help another mother so she does not have to go through all the guess work I did. Best of luck!