ZITHROMAX (azithromycin for injection) is indicated for the treatment of patients with infections caused by susceptible strains of the designated microorganisms in the conditions listed below.

As recommended dosages, durations of therapy, and applicable patient populations vary among these infections, please seeDOSAGE AND ADMINISTRATION for dosing recommendations.Community-acquired pneumonia due to Chlamydia pneumoniae, Haemophilus influenzae, Legionella pneumophila, Moraxella catarrhalis, Mycoplasma pneumoniae, Staphylococcus aureus, or Streptococcus pneumoniae in patients who require initial intravenous therapy.Pelvic inflammatory disease due to Chlamydia trachomatis, Neisseria gonorrhoeae, or Mycoplasma hominis in patients who require initial intravenous therapy.

If anaerobic microorganisms are suspected of contributing to the infection, an antimicrobial agent with anaerobic activity should be administered in combination with ZITHROMAX.ZITHROMAX (azithromycin for injection) should be followed by ZITHROMAX by the oral route as required.

(See DOSAGE AND ADMINISTRATION.)Appropriate culture and susceptibility tests should be performed before treatment to determine the causative microorganism and its susceptibility to azithromycin.

Therapy with ZITHROMAX may be initiated before results of these tests are known; once the results become available, antimicrobial therapy should be adjusted accordingly.To reduce the development of drug-resistant bacteria and maintain the effectiveness of ZITHROMAX (azithromycin) and other antibacterial drugs, ZITHROMAX (azithromycin) should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria.

When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy.

In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

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Infection -- Invasion of the host organism by microorganisms that can cause pathological conditions or diseases.

Pneumonia -- Inflammation of any part, segment or lobe, of the lung parenchyma.

Mycoplasma pneumonia -- Interstitial pneumonia caused by extensive infection of the lungs (LUNG) and BRONCHI, particularly the lower lobes of the lungs, by MYCOPLASMA PNEUMONIAE in humans. In SHEEP, it is caused by MYCOPLASMA OVIPNEUMONIAE. In CATTLE, it may be caused by MYCOPLASMA DISPAR.

Pelvic Inflammatory Disease -- A spectrum of inflammation involving the female upper genital tract and the supporting tissues. It is usually caused by an ascending infection of organisms from the endocervix. Infection may be confined to the uterus (ENDOMETRITIS), the FALLOPIAN TUBES; (SALPINGITIS); the ovaries (OOPHORITIS), the supporting ligaments (PARAMETRITIS), or may involve several of the above uterine appendages. Such inflammation can lead to functional impairment and infertility.

Communicable Diseases -- broad class of diseases whose causative agents may be passed between individuals in many different ways.

ZITHROMAX is contraindicated in patients with known hypersensitivity to azithromycin, erythromycin, any macrolide or ketolide antibiotic.

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Hypersensitivity -- Altered reactivity to an antigen, which can result in pathologic reactions upon subsequent exposure to that particular antigen.

Serious allergic reactions, including angioedema, anaphylaxis, and dermatologic reactions including Stevens Johnson Syndrome and toxic epidermal necrolysis have been reported rarely in patients on azithromycin therapy.

Although rare, fatalities have been reported.

(See CONTRAINDICATIONS.) Despite initially successful symptomatic treatment of the allergic symptoms, when symptomatic therapy was discontinued, the allergic symptomsrecurred soon thereafter in some patients without further azithromycin exposure.

These patients required prolonged periods of observation and symptomatic treatment.

The relationship of these episodes to the long tissue half-life of azithromycin and subsequent prolonged exposure to antigen is unknown at present.If an allergic reaction occurs, the drug should be discontinued and appropriate therapy should be instituted.

Physicians should be aware that reappearance of the allergic symptoms may occur when symptomatic therapy is discontinued.Pseudomembranous colitis has been reported with nearly all antibacterial agents and may range in severity from mild to life-threatening.

Therefore, it is important to consider this diagnosis in patients who present with diarrhea subsequent to the administration of antibacterial agents.Treatment with antibacterial agents alters the normal flora of the colon and may permit overgrowth of clostridia.

Studies indicate that a toxin produced by Clostridium difficile is a primary cause of "antibiotic-associated colitis."After the diagnosis of pseudomembranous colitis has been established, therapeutic measures should be initiated.

Mild cases of pseudomembranous colitis usually respond to discontinuation of the drug alone.

In moderate to severe cases, consideration should be given to management with fluids and electrolytes, protein supplementation, and treatment with an antibacterial drug clinically effective against Clostridium difficile colitis.