Targeted Therapy of Bronchiolitis Obliterans Syndrome

Inclusion Criteria:

* Diagnosis of BOS after HCT within the 6 months before study enrollment; for this study, BOS is defined as:

* Forced expiratory volume in 1 second (FEV1) \< 75% of the predicted normal and FEV1 to slow or inspiratory vital capacity ratio (FEV1/SVC or FEV1/IVC) =\< 0.7, both measured before and after administration of bronchodilator OR
* Pathologic diagnosis of BOS demonstrated by lung biopsy
* The baseline absolute FEV1 must be \>= 10% lower than the pre-transplant absolute FEV1 as defined by the pre-transplant FEV1 minus the baseline FEV1, both measured before administration of a bronchodilator
* Participant (or parent/guardian) has the ability to understand and willingness to sign a written consent document

Exclusion Criteria:

* Recurrent or progressive malignancy requiring anticancer treatment
* Known history of allergy to or intolerance of montelukast, zafirlukast, azithromycin, erythromycin, or clarithromycin
* Pregnancy or nursing; all females of childbearing potential must have a negative serum or urine pregnancy test \< 7 days before study drug administration
* Transaminases \> 5 X upper limit of normal (ULN)
* Total bilirubin \> 3 X ULN
* Chronic treatment with any inhaled steroid for \> 1 month in the past three months
* Treatment with montelukast or zafirlukast for \> 1 month during the past three months
* Treatment with prednisone at \> 1.2 mg/kg/day (or equivalent steroid)
* Treatment with rifampin or phenobarbital, aspirin at doses \> 325 mg/day, or ibuprofen at doses \> 1200 mg/day
* Treatment with any Food and Drug Administration (FDA) non approved study medication within the past 4 weeks; off-label treatment with an FDA-approved medication is allowed
* Chronic oxygen therapy
* Evidence of any viral, bacterial or fungal infection involving the lung and not responding to appropriate treatment
* Clinical asthma (variable and recurring symptoms of airflow obstruction and bronchial hyper-responsiveness)
* Any condition that, in the opinion of the enrolling investigator, would interfere with the subject's ability to comply with the study requirements
* Uncontrolled substance abuse or psychiatric disorder
* Inability to perform pulmonary function tests (PFT) reliably, as determined by the enrolling investigator or PFT lab
* Life expectancy \< 6 months at the time of enrollment as judged by the enrolling investigator
* Baseline post-bronchodilator FEV1 \< 20% of predicted normal before or after albuterol