azithromycin
(ay zi thro my' sin)
Zithromax, Zmax
Pregnancy Category B
Drug class
Macrolide antibiotic
Therapeutic actions
Bacteriostatic or bactericidal in susceptible bacteria.
Indications
· Treatment of lower respiratory infections: Acute bacterial exacerbations of COPD due to H. influenzae, Moraxella catarrhalis, S. pneumoniae; community-acquired pneumonia due to S. pneumoniae, H. influenzae
· Treatment of lower respiratory infections: Streptococcal pharyngitis and tonsillitis due to Streptococcus pyogenes in those who cannot take penicillins
· Treatment of uncomplicated skin infections due to Staphylococcus aureus, S. pyogenes, Streptococcus agalactiae
· Treatment of nongonococcal urethritis and cervicitis due to C. trachomatis; treatment of PID
· Treatment of acute sinusitis
· Treatment of otitis media caused by H. influenzae, M. catarrhalis, S. pneumoniae in children > 6 mo
· Treatment of pharyngitis and tonsillitis in children > 2 yr who cannot use first-line therapy
· Prevention and treatment of disseminated Mycobacterium avium complex (MAC) in patients with advanced AIDS
· Treatment of patients with mild to moderate acute bacterial sinusitis caused by H. influenzae, Moracellis catarrhalis, Streptococcus pneumoniae (Zmax)
· Treatment of mild to moderate community-acquired pneumonia caused by Chlamydophila pneumoniae, H. influenzae, Mycoplasma pneumoniae, Streptococcus pneumoniae (Zmax)
· Unlabeled uses: Uncomplicated gonococcal infections caused by N. gonorrhoeae; gonococcal pharyngitis caused by N. gonorrhoeae; chlamydial infections caused by C. trachomatis; prophylaxis after sexual attack
Contraindications and cautions
· Contraindicated with hypersensitivity to azithromycin, erythromycin, or any macrolide antibiotic.
· Use cautiously with gonorrhea or syphilis, pseudomembranous colitis, hepatic or renal impairment, lactation.
Available forms
Tablets—250, 500, 600 mg; powder for injection—500 mg; powder for oral suspension—100 mg/5 mL, 200 mg/5 mL, 1 g/packet; bottles—2 g to be reconstituted with 60 mL water (Zmax)
Dosages
ADULTS
· Mild to moderate acute bacterial exacerbations of COPD, pneumonia, pharyngitis and tonsillitis (as second-line): 500 mg PO single dose on first day, followed by 250 mg PO daily on days 2–5 for a total dose of 1.5 g or 500 mg/day PO for 3 days.
· Nongonococcal urethritis and cervicitis due to C. trachomatis: A single 1-g PO dose.
· Gonococcal urethritis and cervicitis: A single dose of 2 g PO.
· Disseminated MAC infections: For prevention, 1,200 mg PO taken once weekly. For treatment, 600 mg/day PO with etambutol.
· Acute sinusitis: 500 mg/day PO for 3 days.
· Mild to moderate acute bacterial sinusitis, community-acquired pneumonia: 2 g/day PO as a single dose (Zmax).
PEDIATRIC PATIENTS
· Otitis media: Initially, 10 mg/kg PO as a single dose, then 5 mg/kg on days 2–5 or 30 mg/kg PO as a single dose.
· Community-acquired pneumonia: 10 mg/kg PO as a single dose on first day, then 5 mg/kg PO on days 2–5.
· Pharyngitis or tonsillitis: 12 mg/kg/day PO on days 1–5.
· Acute sinusitis: 10 mg/kg/day PO for 3 days.
Pharmacokinetics
Route | Onset | Peak | Duration |
Oral | Varies | 2.5–3.2 hr | 24 hr |
Metabolism: T1/2: 11–48 hr
Distribution: Crosses placenta; enters breast milk
Excretion: Bile, urine—unchanged
Adverse effects
· CNS: Dizziness, headache, vertigo, somnolence, fatigue
· GI: Diarrhea, abdominal pain, nausea, dyspepsia, flatulence, vomiting, melena, pseudomembranous colitis
· Other: Superinfections, angioedema, rash, photosensitivity, vaginitis
Interactions
Drug-drug
· Decreased serum levels and effectiveness of azithromycin with aluminum and magnesium-containing antacids
· Possible increased effects of theophylline
· Possible increased anticoagulant effects of warfarin
Drug-food
· Food greatly decreases the absorption of azithromycin
Nursing considerations
Assessment
· History: Hypersensitivity to azithromycin, erythromycin, or any macrolide antibiotic; gonorrhea or syphilis, pseudomembranous colitis, hepatic or renal impairment, lactation
· Physical: Site of infection; skin color, lesions; orientation, GI output, bowel sounds, liver evaluation; culture and sensitivity tests of infection, urinalysis, LFTs, renal function tests
Interventions
· Culture site of infection before therapy.
· Administer on an empty stomach 1 hr before or 2–3 hr after meals. Food affects the absorption of this drug.
· Prepare Zmax by adding 60 mL water to bottle, shake well.
· Counsel patients being treated for STDs about appropriate precautions and additional therapy.
Teaching points
· Take the full course prescribed. Do not take with antacids. Tablets and oral suspension can be taken with or without food.
· Prepare Zmax by adding 60 mL (1/4 cup) water to bottle, shake well, drink all at once.
· You may experience these side effects: Stomach cramping, discomfort, diarrhea; fatigue, headache (medication may help); additional infections in the mouth or vagina (consult with health care provider for treatment).
· Report severe or watery diarrhea, severe nausea or vomiting, rash or itching, mouth sores, vaginal sores.
Adverse effects in Italic are most common; those in Bold are life-threatening.
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