This is from a care takers perspective and expertise over 10 years

My wife had NASH she was deemed disabled due to the liver failure and the brain tumor that caused the Nash so she stayed home. However, she had bathroom issues with lactulose at higher dosages . My experience as a caregiver was that it really depended on the dosage and that is a tricky critter to manage. The hepatologist had her on 40 g three times a day and it seemed like we were always having run ins with high ammonia levels creeping up . It was only when I discovered that the hospital was using 60 g three times a day and told hepatologist that we figured out she need a slightly larger dose . That increase the frequency of incidents with accidents .Plus My wife had a really hard time keeping it down because of the taste . I was never able to find a way to mask it some people have had luck with juices, chocolate, milk, etc. We switched to the powdered form 0 taste she could take it in bottled water but it was $500 for 30 days vs $100 for 30 days .. Then we had a battle with the new insurance over the extra cost when I changed jobs, the old one was cool with it the new one well not so much and I could not do the $500 a month out of pocket for long .The hepatologist switched my wife to MiraLAX $20 a month OTC .it is not the same mechanism. It does not bind to the ammonia like lactulose does ( or so I read ) . as I remember, it is an osmotic so works differently . However apparently it has a track record of it being effective on some patients but not all. My wife was one of them thank the lord . It is not nearly as brutal on the bathroom end of things as lactulose is . The accidents pretty much went away. I will throw in some caveats .If she picked up a UTI due to the use of Xaifan or a bug . She would slowly start showing symptoms of encephalopathy . I was lucky any bouts with encephalopathy with my wife manifested early on the rather benign tells of hand tremors and then slowed speech cadence it did take me a few rounds with it to figure out her tells, my understanding is everybody’s different . I always kept some of the lactulose on hand and had her take a few doses to help get the ammonia levels down first sign of any tells instead of the MiraLAX Our hepatologist said that was fine (, I never did anything without clearing out with the hepatologist, ) . I’m not a doctor( I fix machines) , but my personal experience with my wife was MiraLAX was great for maintenance, but lactulose was better for getting levels back down if they were up and of course we always got medical attention to ascertain why her ammonia levels had gone up . Every time in her case it was due to some sort of secondary infection.Talk to your hepatologist maybe MiraLAX is a viable option for him . Hope this helps you.