Before starting baseline ECG and LFTs are required
Azithromycin has been known to cause prolongation of the QT interval on ECGs in some patients, which can potentially lead to dangerous Arrhythmias. It can also sometimes cause elevations in liver enzymes. Doing baseline tests allows doctors to identify any pre-existing issues and monitor for any changes while on the drug.
Can be given as prophylaxis to COPD patients with >3 exacerbations requiring steroid therapy and at least one exacerbation requiring hospital admission in the previous year. Prophylaxis with azithromycin should be considered for a minimum of 6-12 months to assess efficacy of reducing exacerbations