Lecture 3-5 Antibiotics

Question 1

What are the functions of Penicillin G and V

Answer 1

• Penicillin G -> IV and IM
• Penicillin V -> Oral
  used in Gram + ( S.Pneumonemia, pyogens and actinomycos )
  used in Gram - ( N.meningitidis and T.pallidium)

Question 2

What are the side effects of Penicillin G and V

Answer 2

1) hypersenstivity ( anaphylaxis, renal failure and rashes) treated by Epinephrine and Corticosteroids
2) Hemolytic anemia ( drug act as haptan and Ig are developed against RBCs because Penicillin and RBCs have similar Antigens)
3) Drug induced interstial nephritis (HS3) ( High keratinine and high eosinophils and IgE)
4) Jarish-Herxhimer reaction ( caused by T.pallidium) ( with the 1st dose of penicillin G patient get fever and systemic reactions )
5) Steve-Jhonson syndrome ( Drug accumlate under skin causing dermal-epidermal detachment and necrosis of the epidermal layer due to T cell attacking it

Question 3

Signs of Steve-jhonson syndrome and risks of it

Answer 3

1- Blue lips, blue spots on trunk and chest
2- Increases the risk of Septic shock

Question 4

What are the penicillin Sensitive Drugs ( AAA)

Answer 4

Amoxicillin ( highest Bioavailability)
Ampicillin
Aminopenicillin

Question 5

What are the usages ( HHEELPSS) and Side effects of Penicillin sensitive Drugs

Answer 5

Usages: H.pylori, H.influenza, E.coli, Listeria moncytogens, Proteus mirabilis, Salmonella and Shigella
Side effects:
1) same as penicillin
2) Pseudomembranous Colitis (V.IMP) caused by usage of amoxicillin for more than 2-3 weeks

Question 6

what is pseudomembranous colitis and how is it treated?

Answer 6

• Pseudomembranous colitis is damage to epithelial layer of cytoskeleton due increase in Clostiridiodes Difficle bacteria in the gut causing diarrhea especially seen in patient with stomach ulcer, You will see White plaques in colon wall
• Treated by Oral Vancomycin

Question 7

What is Piperacillin

Answer 7

Anti-pseudomonal used for P.argenusa because it develops Resistancy alot and it is used with B-Lactamase INH

Question 8

What are the Penicillin Resistant Drugs

Answer 8

Used in bacteria that develop Resistancy to B-lactamse but not enough to destroy the drug.
- Dicloxacillin, Naficillin and Oxalicillin

Question 9

Use and side effects of Penicillin Resistant Drugs

Answer 9

• used in S.auerus ( except MRSA)
• same side effects as penicillin
• not used in MRSA because they have altered PBP
  -> Patient is Post.OP -> MRSA

Question 10

What are cephalosporins

Answer 10

INH cell wall synthesis but less susceptible to penicillinase
include 5 generations

Question 11

What are the 5 generations of Cephalosporins

Answer 11

1st Gen: Cefazolin and Cephalexin
used for PEcK ( Proteous mirabilis, Ecoli, Klabsella)
2nd Gen: Cefactor, Cefoxtin, Cefuroxime and Cefotetan) used for HENS PEcK ( H.influenza, Enterobacter aergnosa, NIsseria and Serratia and PEcK)
3rd Gen: Ceftriaxone, Cefpdoxime, Ceftazidine and Cefixime)
- Ceftriaxone cross BBB-> 1st line for bacterial meningitis and lyme disease and gonorrhea
- Ceftazidime -> for pseudomonas
4th Gen: Cefepim: Inc activity against pseudomonas
5th Gen: MRSA, Enterococcus facilis ( appedicitis)

Question 12

what is the function of Cefazolin

Answer 12

Prevent S-aeurous wound infection used Pre.OPw

Question 13

what is the different between Viral meningits and Bacterial Meningitis

Answer 13

1- Viral: Normal neutrophil but High monocytes
2- Bacterial: High neutrophil

Question 14

what are the side effects of cephalosporins

Answer 14

1- HS
2- Autoimmunity
3- Hemolytic anemia
4-DIsulfiram like reaction
5- Vitamin K deficiency ( due low y-Glutamyl Carboxylase)
6- Nephrotoxicity when used with aminoglyosides
7- Low allergy rate even with penicillin allergic patients

Question 15

what are the B-lactamse INH

Answer 15

1- Clavulanate -> INH Amoxicillin
2- Avibactum -> INH Ceftazidime
3- Sulbactame -> INH Ampicillin
4- Tazobactam -> INH piperecillin

Question 16

what are the Uses of Carbapenems

Answer 16

Imipenem, Meropenem and Ertapenem
always administred with Cilastin to inhibit Renal Dehydropeptidase1 to decrease the inactivation of the drug in renal tubule
- Used in Life threating infections after other drugs have failed
- Ertapenem is not used for pseudomonas

Question 17

what are the side effects of Carbapenems

Answer 17

1- Seizure -> Penem metbaolized accumlate in blood and go to the CSF and then attack neurons and block GABA causing activation of neurons
- Meropenem has low risk of seizure and is stable to renal Dehydropeptidase 1

Question 18

what are the usages of Aztreonam
what is the mechanism of it and it side effects

Answer 18

When patient is super allergic to penicillin
Gram - rods infection, patient cant tolerate aminoglycosides and has Renal failure
- It prevents peptidoglycan corss-linking by binding to PBP
Side effect: diarrhea

Question 19

What is mechanism of action for Vancomycin

Answer 19

-> INH cell wall peptidoglycan formation by binding to D-Ala-D-Ala
- used only for Gram + and Serious multidrug resistant ( MRSA, S.epidermatitis and Sensitive Enterococcus)
-> its given only Orally because plasma level should be low ( due to slow absoprtion)

Question 20

what are the side effects of Vancomycin

Answer 20

1- Nephrotoxicity
2- Ototoxicity
3- Thrombophlebitis ( Renal vein pus accumulation)
4- Red Man syndrome ( with fast infusion Rate causing mast cell degranulation but No IgE )( pseudoallergy) seen in drug abuses, and endocarditis by S.auerus ( treated by Anti-Histamine and slower infusion rate)
5- DRESS syndrome ( type 4HS)( Rash,Eosinophilia, Hepatitis, nephritis and myocarditis)

Question 21

what is the mechanism of resistance to Vancomycin

Answer 21

Aminoacid modification D-Ala-D-Ala to D-Ala-D-Lac