Prior diagnosis or high suspicion for asthma based on investigator judgment; pulmonary edema, pneumonia, interstitial lung disease or significant bronchiectasis based on admission chest x-ray; intubated and mechanically ventilated at the time of evaluation; active liver disease, or transaminase elevations (> 3xULN); history of alcoholism or heavy ethanol use; history of suicidal behavior ≤ 2 years or suicidal ideation ≤ 6 months prior to enrollment; pregnant or lactating females. Those on the following excluded medications: P450 inducers (e.g., rifampicin, phenobarbital, carbamazepine, and phenytoin) and CYP3A4 inhibitors or dual inhibitors that inhibit both CYP3A4 and CYP1A2 simultaneously (e.g., erythromycin, ketoconazole, fluvoxamine, enoxacin, cimetidine.