CeftazidiMe

Absorption

Ceftazidime administered intravenously in healthy males produced mean Cmax values of between 42 and 170 μg/mL for doses between 500 mg and 2 g, and are reached immediately following the end of the infusion period. The Cmax for 1 g of ceftazidime administered intramuscularly is attained approximately one hour following injection and is between 37 and 43 mg/L. Following intramuscular administration of 500 mg and 1 g of ceftazidime, the serum concentration remained above 4 μg/mL for six and eight hours, respectively.
Ceftazidime Cmax and AUC show linear proportionality to the dose over the therapeutic range. In individuals with normal renal function, ceftazidime given intravenously every eight hours for 10 days as either 1 or 2 g doses showed no accumulation.

Toxicity

Ceftazidime overdosage has occurred in patients with renal failure. Reactions included seizure activity, encephalopathy, asterixis, neuromuscular excitability, and coma. Patients who receive an acute overdosage should be carefully observed and given supportive treatment. In the presence of renal insufficiency, hemodialysis or peritoneal dialysis may aid in the removal of ceftazidime from the body.

Description

In ceftazidime the oxime moiety is more complex, containing two methyl groups and a carboxylic acid. This assemblage conveys even more pronounced β-lactamase stability, greater anti–Pseudomonas aerugi nosa, and increased activity against Gram-positive organisms. The C-3 side chain has been replaced by a charged pyridinium moiety. The latter considerably enhances water solubility and also highly activates the β-lactam bond toward cleavage. The drug must be protected against heat and light and may darken without significant loss of potency. It is not stable under some conditions. such as the presence of aminoglycosides and vancomycin. It also is attacked readily in sodium bicarbonate solutions. Resistance is mediated by chromosomally mediated β-lactamases and by lack of penetration into target bacteria. Otherwise, it has a very broad antibacterial spectrum.

The Uses of CeftazidiMe

Like most of the third-generation cephalosporin antibiotics described above, ceftazidime has a broad spectrum of antimicrobial action, including the most clinically important microorganisms: Gram-positive, Gram-negative, aerobic, and anaerobic. It is resistant to most beta-lactamases of Gram-positive and Gram-negative bacteria. It is used for treating most serious bacterial infections. Synonyms of this drug are fortum, ceftim, stacef, and tazicef.

Indications

Ceftazidime is indicated for the treatment of lower respiratory tract infections, skin and skin structure infections, urinary tract infections, bacterial septicemia, bone and joint infections, gynecologic infections, intra-abdominal infections (including peritonitis), and central nervous system infections (including meningitis) caused by susceptible bacteria.
Ceftazidime is indicated in combination with avibactam to treat infections caused by susceptible Gram-negative organisms, including complicated intra-abdominal infections (cIAI), in conjunction with metronidazole, and complicated urinary tract infections (cUTI), including pyelonephritis, in patients aged three months and older. This combination is also indicated to treat hospital-acquired and ventilator-associated bacterial pneumonia (HABP/VABP) in patients aged 18 years and older.
In all cases, to mitigate the risk of bacterial resistance and preserve clinical efficacy, ceftazidime should only be used for infections that are confirmed or strongly suspected to be caused by susceptible bacterial strains.

Background

Bacteria possess a cell wall comprising a glycopeptide polymer commonly known as peptidoglycan, which is synthesized and remodelled through the action of a family of enzymes known as "penicillin-binding proteins" (PBPs). β-lactam antibiotics, including cephalosporins, are PBP inhibitors that, through inhibition of essential PBPs, result in impaired cell wall homeostasis, loss of cell integrity, and ultimately bacterial cell death. Ceftazidime is a third-generation cephalosporin with broad-spectrum antibacterial activity, including against some treatment-resistant bacteria such as Pseudomonas aeruginosa.
Ceftazidime was approved by the FDA on July 19, 1985, and is currently available either alone or in combination with the non-β-lactam β-lactamase inhibitor avibactam to treat a variety of bacterial infections.

What are the applications of Application

Ceftazidime is an antimicrobial small molecule

Pharmacokinetics

Ceftazidime is a semisynthetic, broad-spectrum, third-generation cephalosporin antibiotic that is bactericidal through inhibition of enzymes responsible for cell-wall synthesis, primarily penicillin-binding protein 3 (PBP3). Among cephalosporins, ceftazidime is notable for its resistance to numerous β-lactamases and its broad spectrum of activity against Gram-negative bacteria, including Pseudomonas aeruginosa. However, it is less active than first- and second-generation cephalosporins against Staphylococcus aureus and other Gram-positive bacteria and also has low activity against anaerobes. Ceftazidime has confirmed activity against clinically relevant Gram-negative bacteria including Citrobacter spp., Enterobacter spp., Klebsiella spp., Proteus spp., Serratia spp., _Escherichia coli, Haemophilus influenzae, Neisseria meningitidis, Pseudomonas aeruginosa, and some Gram-positive bacteria including Staphylococcus spp. and Streptococcus spp. There are also in vitro data for ceftazidime efficacy against a wide variety of other bacteria, such as Acinetobacter baumannii and Neisseria gonorrhoeae, but no clear clinical studies to support the use of ceftazidime for infections caused by these bacteria.
Although β-lactam antibiotics like ceftazidime are generally well tolerated, there remains a risk of serious acute hypersensitivity reactions, which is higher in patients with a known allergy to ceftazidime or any other β-lactam antibiotic. As with all antibiotics, ceftazidime may result in the overgrowth of non-susceptible organisms and potentially serious effects including Clostridium difficile-associated diarrhea (CDAD); CDAD should be considered in patients who develop diarrhea and, in confirmed cases, supportive care initiated immediately. Ceftazidime is primarily renally excreted such that high and prolonged serum concentrations can occur in patients with renal insufficiency, leading to seizures, nonconvulsive status epilepticus (NCSE), encephalopathy, coma, asterixis, neuromuscular excitability, and myoclonia. Treatment may lead to the development or induction of resistance with a risk of treatment failure. Periodic susceptibility testing should be considered, and monotherapy failure may necessitate the addition of another antibiotic such as an aminoglycoside. Cephalosporin use may decrease prothrombin activity, which may be improved by exogenous vitamin K. Inadvertent intra-arterial administration of ceftazidime may result in distal necrosis.

Metabolism

Ceftazidime is not appreciably metabolized.