antibiotics simplified
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Antibiotics
By :
Abdullah Taskin -4th year med. Student -
BY : Abdullah Taskin 4th y.
•Classified according to their MOA into :
BY : Abdullah Taskin 4th y.
BY : Abdullah Taskin 4th y.
BY : Abdullah Taskin 4th y.
Penicillin's
1. Benzyl penicillin 2. Aminopenicillin (ampicillin IV - amoxicillin PO)3. Isoxozoyl penicillin (cloxacillin, methicillin, ) 4. Ureidopenicillin ( piperacillin ) 5. Lactamase Inhibitors (Augmentin – tazobactam ) 6. Cephalosporins ( 1 , 2 , 3 & 4 ) 7. Carbapenems (imipenem ) 8. Vancomycin (Vancocin®)
BY : Abdullah Taskin 4th y.
penicillin Coverage :
GP exceptStaphylococcus, Enterococcus
Oral anaerobes(except
Bacteroides, Treponema)
MOA :Bactericidal:
β-lactam inhibits (PBP) and
prevents cross-linking of
peptidoglycans
Indications:actinomycosis, streptococcalpharyngitis,
streptococcal skin and soft
tissue infections, syphilis
Contraindications:Hypersensitivity to
penicillinBY : Abdullah Taskin 4th y.
Aminopenicillin( Amoxicillin )
Coverage :sam as
B.penicillin
MOA :sam as
B.penicillin
Indications:bacterial meningitis ,
endocarditis , streptococcal ,
part of H. pylori treatment, UTI
Contraindications:Hypersensitivity to
penicillinBY : Abdullah Taskin 4th y.
Isoxozoyl penicillin(methicillin )
Coverage :sam as B.penicillin
MOA :sam as B.penicillin
Indications ( only diff. ) :also cover some staph.a
Contraindications:Hypersensitivity to
Penicillin&
> Interstitial nephritis
BY : Abdullah Taskin 4th y.
Ureidopenicillin(Tazocin®)
Coverage :sam as
B.penicillin
MOA :sam as
B.penicillin
Indications :Same as penicillin &GN: Pseudomonas
Anaerobes
Enterococcus
Contraindications:Hypersensitivity to
penicillinBY : Abdullah Taskin 4th y.
Lactamase Inhibitors (Augmentin®)
Coverage :sam as B.penicillin
MOA :sam as B.penicillin
Indications :Same as penicillin
+/&Staphylococcus
H. influenzaeEnterococcus
Contraindications:Hypersensitivity to
Penicillin&
jaundice or hepatic
dysfunction
BY : Abdullah Taskin 4th y.
Cephalosporins ( 1 , 2 , 3 & 4 )
widely used
BY : Abdullah Taskin 4th y.
Coverage :GP except
Enterococcus&
GN exceptE. coli,
Klebsiella, Proteus
MOA :same as penicillin
(B-lactam)
Indications:GP “more” & GN
Contraindications:
Hypersensitivity to Penicillin or ceha.S.
&Nephrotoxicity
Ceph.S. 1st
(cephalexin , cefazolin)
BY : Abdullah Taskin 4th y.
Coverage :GP week
& GN&
anaerobes
MOA :same as penicillin
(B-lactam)
Contraindications:Hypersensitivity to
Penicillin or ceha.S.
Ceph.S. 2nd (Ceftin®) , Cefprozil (Cefzil®))
BY : Abdullah Taskin 4th y.
Coverage :GP
Staph & strep.&
GNbroad
+ pseudomonas
MOA :same as penicillin
(B-lactam)
Indications:RTI, gonorrhea (use cefixime),
meningitis, septicemia, abdominal infections
Contraindications:Hypersensitivity to
Penicillin or ceha.S.
Ceph.S. 3rd
(cefixime, ceftriaxone , cefotaxime& ceftazidime )
BY : Abdullah Taskin 4th y.
Coverage :(good for gram +ve and –ve)
& pseudomonas
“penetrates the CSF”
MOA :same as penicillin
(B-lactam)
Contraindications:Hypersensitivity to
Penicillin or ceha.S.
Ceph.S. 4th
(cefepime)
BY : Abdullah Taskin 4th y.
Cephalosporins (β-Lactam) :
a) Renal elimination
b) Ceftriaxone & Cefoperazone biotransformation in the liver.
c) Thrombocytopenia associated with cefamandole and cefoperazone NOT cefotetan!!
d) Pyrogenic (highest rates of drug induced fever)
BY : Abdullah Taskin 4th y.
Coverage :GN only
& work with
aminoglycosides
MOA :(B-lactam)
Indications:patients who are allergic to penicillins
or cephalosporins
Contraindications:
Not allergic .
Monobactams β-Lactam Aztreonam
BY : Abdullah Taskin 4th y.
Coverage :GP except
Enterococcus, MRSA
GN includingPseudomonas + Enterobacter
Anaerobes
MOA :(B-lactam)
Indications:LARGEST SPECTRUM OF ACTIVITY of any B-lactam
Rx: Septicemia of unknown origin
Major disadvantages:metabolize by kidney > cause decreased urinary
concentration. SE: seizers ,rashso IMIPENAM + CILASTATIN (inhibitor of
enzyme) are given
together.
Carbapenams β-Lactam:(Imipenam )
BY : Abdullah Taskin 4th y.
Coverage :GP except
Enterococcus, MRSA
GN includingPseudomonas + Enterobacter
Anaerobes
MOA :(B-lactam)
Major disadvantages:not need CILASTATIN
&Less seizures
Carbapenams β-Lactam:(meropenem )
BY : Abdullah Taskin 4th y.
Coverage :GP (strong)
MOA :Glycopeptide
stearicallyinhibits addition of
peptidoglycan subunits
Indications:GP: (RESISTANT to methicillin)
e.g. MRSA & MRSEmust be given IV NO GI
Major disadvantages:Red Man Syndrome
, Nephrotoxicity , Ototoxicity , Neutropenia, Thrombocytopenia
NON β-Lactam:( VANCOMYCIN )
BY : Abdullah Taskin 4th y.
Coverage :Gram +ve and –
ve spectrum
MOA :inhibit cell wall
Indications:SINGLE DOSE Of uncomplicated UTI :
treatment of ONLY IN FEMALES!!
NON β-Lactam:(FOSFOMYCIN )
BY : Abdullah Taskin 4th y.
Contraindicated in pregnancy
1. Aminoglycosides
2. Erythromycin
3. Clarithromycin
4. Tetracyclines
5. Fluoroquinolones
BY : Abdullah Taskin 4th y.
Protein synthesis inhibitors :
BY : Abdullah Taskin 4th y.
Protein synthesis inhibitors
50 S 30 S
A- Macrolides B- Lincosamides
1) Erythromycin
2) clarithromycin
3) azithromycin
1) clindamycin
2) Chloramphenico
3) linezolid
1- Aminoglycosides
2- Tetracyclines
BY : Abdullah Taskin 4th y.
Coverage :GP except
Enterococcus&
GN“Atypicals”
MOA :inhibit 50 S
Indications:Clarithromycin = H.pyloricAzithromycin = Co-drug of choice for Chlamydia & Safe in pregnancy .
Major disadvantages:GI upset , acute cholestatic hepatitis
Prolonged QTHypersensitivity
Macrolides
BY : Abdullah Taskin 4th y.
Coverage :GP except
Enterococcus&
Anaerobes
MOA :inhibit 50 S
clindamycin =Pseudomembranous colitisChloramphenicol= Aplastic anemia & Grey baby syndrome
linezolid = HTN , myelosuppressionoptic neuropathy, peripheral neuropathy
clindamycin
BY : Abdullah Taskin 4th y.
Coverage :GN &
psudomonas
MOA :inhibit 30 S
Indications:G - & no alternatives .
Major disadvantages:Nephrotoxicity
Ototoxicity
Aminoglycosides
BY : Abdullah Taskin 4th y.
Coverage :GP
AnaerobesAtypicals:
Chlamydophila, Mycoplasma,Treponemaprophylaxis
MOA :inhibit 30 S
Indications:Rickettsial infections, Chlamydophila, acne malaria prophylaxis (doxycycline).
Major disadvantages:Hepato-renal toxicity, Fanconi’s syndrome,
Photosensitivity, Teratogenic, Yellow teeth and stunted , bone growth in children,( not in preg.)
Tetracyclines
BY : Abdullah Taskin 4th y.
Coverage :Poor GP activity
GN
AtypicalsFIncludes anaerobes
No Pseudomonas coverage
except : ciprofloxacin
MOA :Inhibits DNA gyrase
Dysglycemia
Indications:Only use when necessaryto prevent resistance
Major disadvantages:Allergy , Seizures , Prolonged QT
TOPOISOMERASE INHIBITORS :Fluoroquinolones
BY : Abdullah Taskin 4th y.
Coverage :GPC
N. meningitidisH. influenza
Mycobacteria
MOA :Inhibits RNA polymerase
Indications:TB , latent TB , Endocarditis & prophlaxis N. meningitides exposure
Major disadvantages:Hepatic dysfunction, P450, Orange
tears/saliva/urine & Jaundice
TOPOISOMERASE INHIBITORS :Rifampin
BY : Abdullah Taskin 4th y.
Coverage :AnaerobesProtozoa
MOA :Forms toxic
metabolites inbacterial cell which
damagemicrobial DNA
Indications:Protozoal infections(trichomonas, amebiasis,giardiasis), bacterial vaginosis, anaerobic bacterial infections
Major disadvantages:Seizures
Peripheral neuropathy ,
TOPOISOMERASE INHIBITORS :Metronidazole (Flagyl®)
BY : Abdullah Taskin 4th y.
Coverage :GP
GN: entericNocardia
Other: Pneumocystis,Toxoplasmosis
MOA :Inhibits folic acid
production(TMP inhibits DHFR and
SMX is a competitive inhibitor of PABA)
Major disadvantages:Hepatitis , Stevens Johnson syndromeTMP:- Megaloblastic anemia- Leuko/granulocytopenia- HyperkalemiaSMX:- Hypersensitivity- Interstitial nephritis- BM suppression
ANTI-METABOLITE:Trimethoprim- Sulfamethoxazole
(TMP/SMX)
BY : Abdullah Taskin 4th y.
Remain :
• Antimyobacterial ( rifampicin covered above )
BY : Abdullah Taskin 4th y.
Appendix
BY : Abdullah Taskin 4th y.
Basic : G.ngative vs. G.positive
BY : Abdullah Taskin 4th y.
BY : Abdullah Taskin 4th y.
Properties of penicillin :• All penicillin has Beta lactam ring .
• Trans-peptidase or (penicillin-binding protein)• Function : Synthesis of peptidoglycan layer .
• To be effective Penicillin must :
I. Penetrate cell layer II. Keeps it beta lactam ring intact III.Bind to Trans-peptidase .
BY : Abdullah Taskin 4th y.
How bacteria defended from penicillin ?
In three ways :
1) G. negatives prevent penetration of cell layers by alteration of porins.
2)G. negatives destroy beta-lactam in periplasmic space .
3) Bacteria inhibit binding of B.lactam to trans-peptidase by altering structure of Trans-peptidase .
BY : Abdullah Taskin 4th y.
References :
• Ananthanarayan & Pinker’s 8th edition .
• Clinical Microbiology Made Ridiculously Simple – 3rd edition
BY : Abdullah Taskin 4th y.
Thank you …
BY : Abdullah Taskin 4th y.
BY : Abdullah Taskin 4th y.
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