I split mine up. I am also on synthroid so when I wake up, I take it. I wait 2 hours and take my first dose of ethambutol and my only dose of azithomycin. Before I go to bed I take my other dose of ethambutol and rifampin. I have not had gut issues and I've been on for a year. I do have ringing in my ears and it wouldn't matter what time of day I took my drugs for that. I am on 3 times a week too but they are talking about going to daily. If someone has a better regimen I'd like to hear it too. The rifampin was interfering with my synthroid. It seems to be working giving a 2 hour split.