The beta-lactam antibiotics share common chemical features and include penicillins and cephalosporins. Their primary action
is to interfere with the cell walls of the bacteria that are causing your infection.
Penicillins The most widely prescribed antibiotic for sinusitis has been amoxicillin (Amoxil, Polymox, Trimox, or any generic formulation). Amoxicillin is inexpensive and at one time was highly effective against the Streptococcus pneumoniae bacteria. However, bacterial resistance to amoxicillin has increased significantly, both among Streptococcus pneumoniae and H. influenzae. Amoxicillin-clavulanate (Augmentin) is known as augmented penicillin and is often used. Augmentin works against a wide spectrum of bacteria and is more effective against resistant strains than amoxicillin alone because the clavulanate strengthens the amoxicillin.
Ampicillin is another form of penicillin. It is an inexpensive alternative to amoxicillin but requires more doses and has more severe gastrointestinal side effects than amoxicillin. There is significant resistance to ampicillin. Dicloxacillin is a penicillin that can be used if there is an abscess in the sinus because it is effective against Staphylococcus aureus. UniSyn is available for intravenous use for more severe cases.
Cephalosporins These broad-spectrum antibiotics are used against Streptococcus pneumoniae and some are effective against H. influenzae. They are often classed by “generation.”
■ First-generation agents include cephalexin (Keflex), cefadroxil (Duricef), and cefaclor (Ceclor).
■ Second - and third-generation drugs include cefuroxime (Ceftin), cefprozil (Cefzil), cefpodoxime (Vantin), loracarbef (Lorabid), ce - fixime (Suprax),and cefdbuten (Cidex). These are effective against a wide spectrum of bacteria and are increasingly used for respiratory infections. There are Streptococcus pneumoniae bacteria that are resistant to cephalosporins. Rocephin is a third-generation cephalosporin that is available only for intravenous use.