Good for combatting certain types of bacteria
Cefazolin is a 1st generation Cephalosporin. While it does well against many gram positive bacteria (typically those with an uncovered, thick outer wall around the cell), it is very ineffective against gram negative bacteria (those with a thin wall that is protected by an extra membrane). While it does not cover everything, Cefazolin is easier on the body than many other antibiotics. For this reason, it is often used as a preoperative prophylaxis, given in IV fluids prior to surgery. Though its usefulness starts to diminish when dealing with "evolutionarily younger" bacteria, which are usually either gram negative or are developing resistances to certain classes of antibiotics, it remains a regularly used staple in the vet med world. It is commonly used for pneumonia, sepsis, certain bladder and urinary tract infections, or in conjunction with antibiotics that target gram negative bacteria to achieve as broad of a spectrum of treatment as possible in an unidentified infection..
From S Dean - Trainer and Former Vet Tech 100 days ago