Improving Tolerance of Treatment of Pulmonary MAC Infections

As part of this study, investigators will review medical records to be sure that the patient
meets the required criteria and is healthy enough to take part in this study.

The study will consist of five separate visits to the Clinical research Center at the
University of Florida and each visit will last anywhere from 6-8 hours. Patients will be
given a diary of questionnaires where they will record when they take their medication and
any side effects they might have. Patients will also have Electrocardiograms (ECGs) to make
sure they are healthy enough to be a participant in the study and to measure the effects of
their medication on their heart. During this study, patients will continue treatment of
their Mycobacterium avium Complex infections. Patients will be observed taking their
medication on each of the five separate days. On each of these days patients will have blood
drawn at 2 and 6 hours after their drugs are taken in order to measure drug levels in their
blood. We will also use this blood to measure levels of proteins and hormones and to make
sure the medications are not affecting the patient's heart. The patient will fill out
several questionnaires and do a dietary assessment online. Investigators will assess the
patient's body make-up using a device called the Bod Pod. The patient will also be assigned
to one of two treatment groups: (1) Ondansetron 8mg (Zofran®, GlaxoSmithKline, Research
Triangle Park, NC) every morning before breakfast versus (2) a dietary supplement prior to
taking daily medication. The patient will be assigned to the first treatment group for a
period of two weeks. On the third study visit investigators will switch the patient to the
second group.

Although the incidence of tuberculosis has decreased in the United States over the last few
decades, the incidence of chronic pulmonary infections with nontuberculous mycobacteria
(NTM) appears to be increasing. Unfortunately, a common problem in the management of these
infections is the inability of elderly patients to tolerate the currently recommended
multidrug regimen of (1) azithromycin or clarithromycin, (2) rifampin or rifabutin, and (3)
ethambutol. The most frequent adverse reactions of MAC treatment are gastrointestinal (GI),
most commonly associated with the macrolides and rifampin. Although macrolide toxicity is
generally dose-related, the role of routine monitoring of drug concentrations and subsequent
dose adjustment has not been studied. The role of anti-emetics or dietary supplements to
mitigate these symptoms is also not defined.

Inclusion Criteria:

- Physician diagnosis of Mycobacterium avium Complex with nodular bronchiectasis

- On daily treatment for Mycobacterium avium Complex consisting of 250mg of
Azithromycin, 600mg of Rifampin, and 15mg/kg of Ethambutol

- Experiencing gastrointestinal symptoms due to their multi-drug treatment regimen

- Has access to the internet

Exclusion Criteria:

- Claustrophobia

- Currently smokes cigarettes

- Persons with disseminated Mycobacterium avium Complex infections

- Persons with a known and diagnosed immunosuppressive disorder (i.e. cancer, HIV)

- Persons with physician diagnosed Irritable Bowel Syndrome, Crohn's Disease, or
Ulcerative Colitis

- Persons with moderate to severe kidney or liver dysfunction

- Persons who are co-colonized with an NTM aside from Mycobacterium avium Complex

- Persons who initially present with a prolonged QT interval (defined as greater 500
milliseconds) on any baseline ECG

- Previous adverse reaction or allergy to Zofran (Ondansetron)