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Doses for the Big 3 meds for MAC
I have had MAC for about 3 or 4 years. I’ve been in the “watch” stage with no meds. I also have Wegeners Disease which is under control but the meds bring down my immune system. I’ve had pneumonia for the last couple of months so my ID doctor is starting me on the Big 3 this week. I’m curious about the dosage that others are taking. Here’s what I have been given:
Azithromycin- 500mg
Ethambutol HCL - 1600 mg
Rifampin - 600mg
All 3 x week starting with the Azithromycin 1st & gradually adding the others.
Does anyone think the ethambutol a high dosage? Im 5’4 & weigh 145lbs.
Thanks for your input.
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I don’t know about the dosage. 3x a week may be different from daily. How often are you seeing an ophthalmologist? Ethambutol can cause optic and peripheral neuropathy.
I will start the meds Monday. I’ve been to an opthamologist to get a baseline & will continue to see him on a regular basis.
@deb62 I don't remember which, but only one of these meds has a different dose depending on weight. But your prescription is the same as mine was when taking 3' per week. The rifampin and ethambutol were lower doses when I took them daily.
You should also get a baseline hearing test and be alert for any changes.
I am glad that your doc is starting the meds one at a time to let your body adjust.
I was on the exact doses as you are. I was weary about the ethambutol dose and questioned the doctor. I weighed a 60kg at the time conversion a little less than you. And it is the ethambutol that is weight based. Unfortunately I experienced neuropathy early in the days of beginning. However, others have had no symptoms so just be aware of anything not the norm for you. Good luck with your treatment.
@cd33 thank you for your response.
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1 Reaction@sueinmn thank you for responding. Yes I go next week to have the hearing test. It sounds like I’m ready to start.
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2 ReactionsI've been on your exact dose and frequency for MAC since Oct 2025. I'm 5'7", 147 lbs. I've had hearing and vision exams showing no problems.
Hi - I'm 5'1", 100 lb. I'd ask the doctor about the criteria for choosing the dose and also how long he expects you'll be on it.
My dosing has been as follows:
Sep-Dec 2025:
Azithromycin- 500mg x 1 tablet = 500 mg Mon, Wed, Fri
Ethambutol HCL - 400 mg x 2 tablets = 800 mg Mon, Wed, Fri
Rifampin - 300mg x 2 tablets = 600 mg Mon, Wed, Fri
Dec 2025 - present (May 2026):
Removed Ethambutol in December, continued the others as above. My cough disappeared 2 weeks into the above regimen and I've been stable since then. I'd love to get off the others as well, but he wants me to be on them for a full year.
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1 Reaction@rc4mc
I was on the big 3 MWF and didn't feel well with the relatively high doses of medication, Rifampin in particular. My UCSF doctor took me off Rifampin and switched me to daily M-F medications at much lower doses. It has worked well for me and now I am adding Arikayce. If you have a hard time with the higher doses, I suggest you ask your doctor about switching to daily doses. Also, I'd like any feedback on Arikayce that anyone can offer. I have read studies that say it is more effective as one of the Big 3, but I am worried about tinnitus, which I already have from Azithrymicin, and the time it takes to nebulize in addition to daily saline nebulizing. I may switch to Chlorfazamine (spelling?) and am interested in learning more about this group's personal experiences and pros and cons of both. Good luck to you.
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1 Reaction@capletcher Thank you! I'm going to ask my doctor again about getting off Rifampin early (like in a couple weeks, when I see him). Then I'd just be on Azithromycin unless he adds something else.