Plastic of this kind is quite rough compared to glass which is smooth, so add some roughness to the glass shader.
But best thing here I suspect would be to make a custom glass shader from the start:
Fresnel to mix refraction and glossy as a standard glass.
However, the refraction part should be mixed with another mix of diffuse and translucency to fake some scattering effect. You could also try some volume scatter, but I find it very costly.
When I append your bottle object, geometry seems far too big and appears very messy.