Pneumonia - Medications

Medications

Dozens of antibiotics are available for treating pneumonia, but selecting the best drug is sometimes difficult. Patients with pneumonia need an antibiotic that is effective against the organism causing the disease. When the organism is unknown, "empiric therapy" is given, meaning the doctor chooses which antibiotic is likely to work based on factors such as the patient's age, health, and severity of the illness.

In determining the appropriate antibiotic, the physician must first answer a number of questions:

• How severe is the pneumonia? Mild-to-moderate cases can be treated at home with oral antibiotics. Severe pneumonia usually needs intravenous antibiotics administered in the hospital.
• If the organism causing the pneumonia is not known, was the disorder community- or hospital-acquired? Different organisms are usually involved in each setting, and the physician can use this information to guess the most likely organism causing the pneumonia.
• If the organism is known, is it typical or atypical? Community-acquired pneumonias, for example, are usually caused by the typical bacteria Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis, which were previously treated with related antibiotics. These antibiotics do not treat organisms such as legionella, mycoplasma, or chlamydia. These organisms are generally treated with a macrolide or possibly a newer quinolone.
• Does the patient have an impaired immune system? Antibiotics used to treat such patients may differ from those used in patients with healthy immune systems.

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Once an antibiotic has been chosen, there are still difficulties:

• Individuals respond differently to the same antibiotic, depending on their age, health, size, and other factors.
• Patients can be allergic to certain antibiotics, thus requiring alternatives.
• Patients may have strains of bacteria that are resistant to certain antibiotics.

Antibiotic Treatments for Community-Acquired Pneumonia

Joint guidelines issued in 2007 by the Infectious Disease Society of America and the American Thoracic Society (ITSA/ATS) recommend that mild CAP in otherwise healthy patients be treated with oral macrolide antibiotics (azithromycin, clarithromycin, or erythromycin).

The British Thoracic Society recommends amoxicillan, or doxycycline or clarithromycin as alternatives.