Cephalosporins

Cephalosporins

Cephalosporins structure

A large class antibiotics related to penicillin; examples include cephalexin, cefazolin and others.

Information about Cephalosporins

The cephalosporins are a family of bactericidal antibiotics structurally related to penicillin which were first derived from the fungus, Cephalosporum acremonium. Their basic structure is similar to penicillin with a thiazolidine and beta-lactam ring, which has a variable side chain.

Mechanism of action of Cephalosporins

Cephalosporins bind to the penicillin-binding proteins on bacteria and inhibit synthesis of the bacterial cell wall, causing cell lysis particularly in rapidly growing organisms. Their differences in activity relate to the range of penicillin-binding proteins that they inhibit. They have a broader activity than the standard penicillins, but are also sensitive to some extent to beta-lactamase.

Types

1. Apple Guava (Psidium guajava) - Apple guava is the most commonly cultivated variety of guava. It is also known as tropical guava and is native to Central and South America. The fruit has a round or oval shape and a greenish-yellow skin that turns yellow when ripe. The flesh is creamy white or pinkish, and it is sweet and fragrant. Apple guava is rich in vitamin C, fiber, and antioxidants.
2. Pineapple Guava (Feijoa sellowiana) - Pineapple guava is also known as feijoa, and it is native to South America. The fruit has a greenish-gray skin that is rough to the touch, and the flesh is creamy white with a sweet and tangy flavor. Pineapple guava is high in vitamin C and antioxidants.
3. Strawberry Guava (Psidium cattleianum) - Strawberry guava is native to South America and is also known as Cattley guava. The fruit has a small size, and its skin is thin, smooth, and red or yellow. The flesh is white, pink, or red and has a sweet and tangy flavor. Strawberry guava is high in vitamin C and antioxidants.
4. Lemon Guava (Psidium guineense) - Lemon guava is native to Brazil and has a round shape with a yellowish-green skin. The flesh is yellow and has a tangy flavor similar to lemon. Lemon guava is rich in vitamin C and antioxidants.

Five generations of cephalosporins have been developed with varying antibacterial activity. Cephalosporins are indicated for infections with susceptible organisms. Cephalosporins have variable oral absorption and many must be given parenterally. In the lists below, formulations that are available in oral and parenteral forms are shown separately.

First generation cephalosporins include cefadroxil, cefazolin, cephalexin, and cephradine, and these are active against many gram-positive cocci, including penicillinase-producing Staphylococcus aureus.

Second generation cephalosporins include cefaclor, cefoxitin, cefprozil, cefonicid, and cefuroxime; these have broader antibacterial activity, and additional sensitive organisms including Citrobacter, Enterobacter, Haemophilus influenzae, Neisseria and Serratia species.

Third generation cephalosporins include cefdinir, cefditoren, cefixime, cefoperazone, cefotaxime, cefpodoxime, ceftazidime, ceftibuten, ceftizoxime, and ceftriaxone, which are less active than first- and second generation drugs against gram-positive bacteria, but more active against gram-negative organisms and have greater stability against beta-lactamases.

Fourth generation cephalosporins include cefepime, which are active against a wide range of both gram-positive and gram-negative organisms.

Fifth generation cephalosporins include ceftaroline and ceftolozane/tazabactam, which are active against a wide range of both gram-positive and gram-negative organisms including methicillin resistant Staphylococcus aureus (MRSA). These agents are sometimes referred to as advanced generation rather than fifth generation cephalosporins.

Side effects of Cephalosporins

Cephalosporins have side effects similar to penicillin, and drug-allergy and hypersensitivity are often (but not always) shared. The cephalosporins in general have been associated with little hepatotoxicity and only rare instances of drug induced liver injury due to these agents have been published. A special exception is ceftriaxone, a third generation cephalosporin which, when given parenterally, can cause biliary sludge with symptoms of cholecystitis and cholestatic jaundice. For these reasons, other than for ceftriaxone, the cephalosporins will be discussed as a general class rather than individual agents, and separately for the intravenous and oral forms.

Liver toxicity of Cephalosporins

A few cephalosporins have been implicated in only a few cases, but in general the liver injury from cephalosporins is similar from case to case. The typical case of liver injury from cephalosporins is a self-limited cholestatic hepatitis with mild if any immunoallergic features that arises 1 to 3 weeks after starting therapy, sometimes occurring after a single parenteral dose.

Oral Cephalosporins

• Cefaclor (2nd)
• Cefadroxil (1st)
• Cefdinir (3rd)
• Cefditoren (3rd)
• Cefixime (3rd)
• Cefpodoxime (3rd)
• Cefprozil (2nd)
• Ceftibuten (1st)
• Cephalexin (1st)
• Cefuroxime (2nd)
• Cephradine (1st)
• Loracarbef (2nd)

Parenteral Cephalosporins

• Cefazolin (1st)
• Cefepime (4th)
• Cefoperazone (3rd)
• Cefotaxime (3rd)
• Cefoxitin (2nd)
• Ceftaroline (5th)
• Ceftazidime (3rd)
• Ceftibuten (3rd)
• Ceftizoxime (3rd)
• Ceftolozane/Tazobactam (5th)
• Cefuroxime (2nd)
• Cephradine (1st)
• Ceftriaxone (3rd)

• Dailymed label info on Cephalosporins
• FDA Cephalosporins

Cephalosporins Resources
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