Reflux in 7 week old baby?

hi my son has been diagnosed with reflux and the doc has prescribed him infant gaviscon but surely its bad to be puttn it in every bottle. it says on leaflet dont use over a long period but the doc seems happy to keep putting it on repeat prescription.if i dnt put it in everybottle all his symptons reappear and hes in agony.so every bottle he has has a sachet of gaviscon on it....how long will he have to keep taking this for??/ help and advice greatly appreciated sorri if this is poor punctuation or dnt make sense windn and feedding baby as i type lol xxxx