Monitor QTc in patients with increased risk

Prolongation of QTc interval. Association with increased cardiovascular mortality in observational studies.

Prolonged half life may contribute to macrolide resistance.

• Other drugs that prolong QTc
• Increases cyclosporine levels
• May increase digoxin levels
• Potential increased risk of rhabdomyolysis when used with statins

Very high tissue penetration and concentration intracellularly means in vivo activity may not be predicted by in vitro testing.