Pharmacological properties of parenteral cephalosporins - Rationale for ambulatory use

Parenteral cephalosporins are among the most frequently used antibiotics in hospital therapy. They are characterised by an extended spectrum of activi ty against Gram-positive and Gram-negative bacteria, and some also have goo d activity against anaerobes. They kill proliferating bacterial cells rapid ly, and generally show only a low tendency to select resistant mutants. How ever, there are cephalosporin compounds which induce cephalosporinases very rapidly in certain microorganisms. Together with other p-lactam antibiotic s, parenteral cephalosporins interfere with bacterial cell wall synthesis b y inhibiting peptido-glycan cross-linkage Because of this specific target, they are nontoxic to mammalian cells, and have a very favourable adverse ef fect profile. The chemical stability of parenteral cephalosporins in aqueou s solution is good. After intravenous injection, high concentrations of the se agents are achieved in serum and tissue. Most cephalosporins are elimina ted unchanged via the kidney, with a half-life of 1 to 2 hours. But there a re also derivatives with a serum half-life of more than 2 and up to 8 hours , allowing 12- or 24-hour dosage intervals. Because of their reliable effic acy and low risk of adverse effects, the parenteral cephalosporins offer a high degree of tolerability even in the setting of outpatient antibiotic th erapy. In particular, the derivatives of the third generation are character ised by unique pharmacological properties.