All the following drugs are used in hepatic encephalopathy except:

L.O.L.A: L-ornithine stimulates the urea cycle, with resulting loss of ammonia. Both L-ornithine and L-aspaate are substrates for glutamate transaminase. Their administration results increased glutamate levels. Ammonia is subsequently used in the conversion of glutamate to glutamine by glutamine synthetase. Ammonia absorption can be decreased by the administration of lactulose, a non-absorbable disaccharide that acts as an osmotic laxative. Rifaximin at a dose of 400 mg taken orally 3 times a day improves hepatic encephalopathy symptoms. Similarly, rifaximin was as effective as neomycin and paromomycin.