28)Cephalosporins

Question 1

Cephalosporins

Answer 1

B-lactam antibiotics

• Used to treat :pneumonia,
• skin & soft tissue infections,
• sinusitis,
• URT infection
• Otitis

Question 2

Mechanism of action

Answer 2

Same as penicillin:

• Bactericidal in growing bacteria
• Attach to specific binding proteins
• Inhibit bacterial cell wall peptidoglycan synthesis
• Inactivate inhibitor of autolytic enzymes in cell wall ⇢ activates bacterial cell lysis & death

Question 3

1st gen

Answer 3

• Oral + IV
• Gram⁺ activity against penicillinase-producing methicillin susceptible staphylococci + streptococci
• Gram^-ve activity against E.coli + Klebsiella pneumoniae
• Eg: Cephalexin, Cefadroxil + Cefazolin

Question 4

2nd gen

Answer 4

• Oral + IV
• ⇣ Gram⁺ activity compared to 1st gen
• ⇡ Gram^-ve activity compared to 1st gen
• Eg: Cefuroxime axetil

Question 5

3rd gen

Answer 5

• Broad Gram^-ve range
• Limited Gram⁺ range
• Treat RT, meningitis, intra-abdominal, skin, URT, bacterial septicaemia + Bone & joint infections
• Non-antipseudomonal ⇢ Ceftriaxone + Cefotaxime
• Anti-pseudomonal ⇢ Ceftazidime

Question 6

4th gen

Answer 6

• Gram⁺ extended spectrum - similar to 1st gen
• Gram^-ve effective ⇢ zwitterions can penetrate outer membrane
• Treat ⇢ pneumonia, URT infection + Skin infections
• Eg: Cefepime IV ⇢ Penetrate BBB w/greater resistance to B-lactamases

Question 7

5th gen

Answer 7

• IV ⇢ well distributed throughout body
• Less susceptible to resistance
• Powerful anti-pseudomonal effect
• Eg: Ceftobiprole + Ceftaroline

Question 8

Side effects

Answer 8

Allergic reactions

Kidney problems

Shortness of breath

Pounding heart

Rash

Craps

Fever

Diarrhoea

Cannot breastfeed on cephalosporins

Answer 9