NOTES FROM THE UNDERGROUND; PWA Health Group - April, 1996
Andy Young

These two studies are important, because many PWAs with less than 100 T cells take Rifabutin to prevent MAC. (Rifabutin use has to be stopped or the dosage changed when used with protease inhibitors.) Rifabutin is currently the only drug approved by the FDA for the prevention of MAC.

In one study, 1200 patients with less than 100 T cells took Rifabutin, Clarithromycin, or both. 9% of patients who took Clarithromycin developed MAC, 15% of those on Rifabutin, and 7% on the combo...not very big differences (in terms of statistical significance). The key finding was that almost 30% of people who took Clarithromycin alone or in the combo developed resistance to it. Clarithromycin is the standard treatment for active MAC infections. Resistance to it before a person actually becomes sick with the monster is way bad news.

The other large trial looked at 699 PWAs on Rifabutin, Azithromycin or both in combination. The combination was again the best preventative treatment. 2.5% of PWAs who took Azithromycin and Rifabutin together got MAC, compared to 8.8% who used Azithromycin alone, and 11.6% who took only Rifabutin. One scary thing is that 11% of people who developed active MAC infections in this study became resistant to both Azithromycin and Clarithromycin. This happens because the two drugs are so similar in chemical structure that resistance to one can be functionally resistant to both. Cross resistance between Azithromycin and Clarithromycin would leave Rifabutin alone as the treatment for an active MAC infection.

These studies tell us that there are other and possibly more effective ways to prevent MAC than just taking Rifabutin alone. The successful use of Azithromycin is really interesting because it only was taken once a week. A potential problem is cross resistance between Azithromycin and Clarithromycin, which also spells trouble in treating an active MAC infection. People do not develop resistance to Rifabutin from taking it, or from the other drugs discussed here, but it was shown in both studies to be the least succesful way to avoid a MAC infection.

As a footnote, Roxithromycin, another antibiotic in the same family as Azithromycin and Clarithromycin, that we carry here, has also been shown to work as MAC prevention and as a treatment for cryptosporidiosis. Treatment and prevention for MAC is a dicey proposition at best. All the medicines are strong and can be difficult to take, both physically and in regards to which other medicines have to be avoided. But truth be told, I’d rather make my doctor work to figure out which drugs of many I should use, than have no options to choose from.

Copyright © 1996 - NOTES FROM THE UNDERGROUND - The PWA Health Group Newsletter. All rights reserved. No part of this publication may be copied or reproduced in any form or by any means without the written permission from the PWA Health Group. NOTE: The PWA Health Group is no longer in existence, as per notification in 2003. An organization called Visionary Health Concepts has succeded them. VHConcepts is a HIV/Hepatitis+ owned and operated health education company specializing in providing free HIV & Hepatitis treatment programs For more information please contact Email: edu@vhconcepts.com. .