Pneumonia - Surgery

Antibiotic and Antiviral Drug Classes

Beta-Lactams

Beta-lactam antibiotics share common chemical features. They include penicillins, cephalosporins, and some newer similar medications. They interfere with bacterial cell walls.

Penicillins. Penicillin was the first antibiotic. There are many forms of this still-important drug:

• Natural penicillins include penicillin G (for intravenous use) and V (for oral use).
• Penicillin derivatives called aminopenicillins, particularly amoxicillin (Amoxil, Polymox, Trimox, Wymox, or any generic formulation), are now the most common penicillins used. Amoxicillin is inexpensive and, at one time, was highly effective against S. pneumoniae. Unfortunately, bacterial resistance to amoxicillin has increased significantly, both among S. pneumoniae and H. influenzae. Ampicillin is similar and is an alternative to amoxicillin, but requires more doses and has more severe gastrointestinal side effects.
• Amoxicillin-clavulanate (Augmentin) is a type of penicillin that works against a wide variety of bacteria. An extended-release form has been approved for treating adults with community-acquired pneumonia caused by bacterial strains that have become partially resistant to penicillin.
• Antistaphylococcal penicillins were developed to treat Staphylococcus aureus. The standard drug was methicillin, but it is no longer used routinely, due to very high rates of resistance in hospital-acquired pneumonias. Resistance in community-acquired Staphylococcus aureus is also increasing. Alternatives include vancomycin and linezolid. There are also other options for this type of bacteria.
• Penicillins used against Pseudomonas aeruginosa include ticarcillin and piperacillin. Piperacillin is more effective than ticarcillin.

Many people have a history of an allergic reaction to penicillin, but research suggests that the allergy may not occur again in a significant number of adults. Skin tests are available to help determine if those with a history of penicillin allergies could use these important antibiotics.

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