Azithromycin

C. diff Risk

Medium

Oral Bioavailability

Moderate

Approximate Cost

Dosing

Respiratory infection: 500 mg PO/IV daily for 3 days, OR 500mg PO/IV on day 1 then 250mg PO/IV daily for 4 days Chlamydia trachomatis: 1g PO x 1 dose

General Information

Common Usage

Community acquired pneumonia, Pertussis, upper respiratory tract infections, Chlamydial infections, mycobacterial infections, Mycobacterium avium complex (MAC) prophylaxis in HIV patients

Drug Monitoring

Monitor QTc in patients with increased risk

Adverse Effects

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

Prolonged half life may contribute to macrolide resistance

Major Interactions

Other drugs that prolong QTc

Increases cyclosporine levels

May increase digoxin levels

Statins increased risk of rhabdomyolysis

Increases INR with warfarin

Additional Information

Very high tissue penetration and concentration intracellularly means in vivo activity may not be predicted by in vitro testing - i.e. Salmonella spp

May exacerbate muscle weakness in persons with myasthenia gravis. Use with caution.

Pharmacology

Antimicrobial class: Macrolide

Pregnancy category: B

Average serum half life: 68.0

Biliary penetration: Therapeutic

CSF penetration: Poor

Lung penetration: Therapeutic

Urine penetration: Poor