Brief Answer:
both of them are supposed to help

Detailed Answer:
Hello,

first of all GERD does not usually go away. If you're prone to reflux then you'll probably have the same problem throughout your life unless a surgical treatment is applied. GERD can be treated though. Ranitidine is an acid lowering agent but not the most potent one. Proton pump inhibitors (like omeprazole for example) are supposed to work better). You can avoid some 'bad habits' to decrease the incidents of reflux too.

Avoiding eating too much, lying down right after eating, drinking a lot of coffee, citrus fruit juice and fatty meals will help. Walking for a while after eating would help.

Regarding your drugs, gaviscon is supposed to reduce or eliminate the symptoms within minutes. Ranitidine works fast too, perhaps not as fast though but has a lasting effect.

I hope you find my comments helpful!
You can contact me again, if you'd like any clarification or further information.

Kind Regards!

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