Constipation severity was significantly lower in the neomycin and rifaximin group ( 28.630.8 ) compared to neomycin alone ( 61.224.1 ) ( P = 0.0042 ) , with greater improvement in constipation ( P = 0.007 ) , straining ( P = 0.017 ) and bloating ( P = 0.020 ) , but not abdominal pain .