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35 Cards in this Set

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Penicillins
Sturcture?
examples?
Core beta lactam ring.
R-group modify acid stability and beta-lactamase susceptibility

e.g. Narrow: Penicillin G/V, cloxacillin. Broad: Ampicillin, piperacillin, ticarcillin
Penicillins
Mech?
Binding to PBPs (Penicillin binding proteins) results in:
1. Activation of autolysins
2. Inhibition of transpeptidase crosslinking of cell wall.
Penicillins
PKs?
1. moderate to poor absorption thru GI tract.
2. VOD 0.1-0.3L/kg
3. Renal elimination mainly
4. half life is 1 hr
Penicillins
SEs?
low!
1. hypersensitivity to beta lactam ring; rash to anaphylaxis
2. seizures and interstitial nephritis at higher concentrations
3. Antibiotic asso. diarrhea (C.difficelle)
Cephalosporins
Mech?
Inhibits crosslinking of bacterial cell walls. With every cephalosporin generation gram+ve activity lost and gram-ve gained.
Cephalosporins
Structure?
examples?
7-cephalosporanic acid.
R-group at position 3 affects PK (methyl -> better oral absorption)
R-group at position 7 affects beta-lactamase stability (methoxy -> better stability but loss of gram +ve spectrum)

eg. cefazolin (1st gen), ceftriaxone & ceftazidime (3rd gen)
Cephalosporins
PKs?
Very similar to penicillins
1. Absorption from GI moderate to poor
2. VOD 0.1-0.4L/kg
3. Renal elimination
4. half life 1-8 hrs
Cephalosporins
SEs?
Again similar to penicillins
1. hypersensitivity
2. cross reactivity with penicillin
3. seizures and interstitial nephritis at higher doses.
4. INR increase with 2nd and 3rd gen due to inhibition of vitK carboxylase.
Beta lactamase inhibitors combinations?
clavulanic acid with ampicillin and ticarcillin

tazobactam with pipercillin
Carbapenems
Mech?
inhibit cell wall synthesis like penicillins and cephalosporins
Carbapenems
Structure?
examples?
beta lactam ring BUT different stereochem making them resistant to beta lactamase

e.g. Meropenem, Imipenem(given with cilastatin to protect from dehydropeptidase)
Carbapenems
SEs?
1. cross react with penicillin
2. seizures at high doses
Vancomycin
Mech?
A glycopeptide that inhibits cell wall synthesis by inhibiting transfer of pentapeptide from carrier to growing polymer

mainly gram+ve spectrum including MRSAs
Vancomycin
PKs?
Usually given parenterally (MRSA) but orally against C.difficelle.
1. not absorbed systemically when given per os
2. VOD 0.5-0.9 L/kg
3. half-life 6-9 hrs
4. Renal clearance
Vancomycin
SEs?
1. ototoxicity
2. nephrotoxicity
3. infusion related rash (red man syndrome)
Vancomycin
Resistance?
1. VRE (Vanco resistant enterococcus)
2. VISA (Vanco intermediate sensitive S.aureus)
3. AAs changes in carrier molecule
Aminoglycosides. Mechanism of Action?
Inhibit protein synthesis by binding to Ribosomal 30S subunit;
1. Inhibit initiation complex
2. Miscode AAs in growing protein chain
3. Cause ribosome to fall off mRNA

Bacteriacidal. good activity against gram -ve aerobes
Aminoglycosides
Properties?
1. Large highly water soluble (Polar)
2. Postively charged (intxn w/ -ve cell wall residues; limited in anaerobes)
3. Bactericidal (often used with cell wall inhibitors)

e.g. gentamicin
Aminoglycosides
PKs?
Concentration Dependent Killing (like Quinolones, unlike Penicillins [time-dependent])
1. low VOD 0.3-0.4L/kg (extracellular space)
2. Absorp'n from GI = poor
3. Renal elimination (think H2O soluble)
4. Poor CNS penetration (think size an charge)
5. short half life 2-3hrs
Aminoglycosides
SEs?
1. nephrotoxicity and ottotoxicity (Readily accumulates in kidneys and inner ear)
2. neuromuscular blockade (presynaptic release, and post-synaptic receptors)
Aminoglycosides
Interactions?
1.Neuromuscular blockage agents
2. Nephrotoxic agents (Vancomycin, cyclosporine)
Aminoglycosides
Resistance?
1. Change in membrane potential (think charge) = less uptake
2. Acetylating and Phosphorylating enzymes mod. drug
Protein inhibitors
Macrolides
Structure?
Mech?
- 14 ring structure
- inhibit protein syn. by reversible binding to 50S subunit.
- Bacteriostatic!

e.g Erythro-, Clarithro-, Azithromycin (the latter two Erythro modified for better oral absorption and less GI SEs)
Macrolides
SEs?
DIs?
- nausea/vomiting, diarrhea (erthro given to diabetics in low dose to stim gut motility)
- QT !

- anti-arrhythmic drugs, will potentiate QT
Protein inhibitors
Lincosamides
Mech?
e.g. clindamycin
- inhibit 50S subunit
- bacteriostatic
- mainly gram+ve aerobe and anaerobe coverage.
Lincosamides
PKs?
SEs?
- good oral absorption and VOD
- good penetration
- liver metabolism
- T1/2 2-3 hrs

- Antibiotic asso. diarrhea
- Resistance increasing in bacteriodes and staph.
Common Fluoroquinolones and Mech. of action
Cipro-, Moxi-, and Levofloxacin.
They inhibit DNA gyrase (opens DNA strands) and topoisomerase (break and re-ligate DNA)
Quinolones
PKs?
1. Very good oral absorption (60-90%), same i.v.
2. VOD good 1-2.5L/kg
3. distributes to most body tissues but not readily to CNS
Quinolones
Resistance?
Increasing: S.pneumoniae, E.coli, Pseudomonas
Quinolones
SEs?
interactions?
1. Glucose abnormalities
2. increases QT interval
3. Al, Mg, Ca decrease absorption, and vise versa (not taken with food)
4. liver enzyme function tests
5. prevent GABA binding to receptor
DNA inhibitors
Metronidazole
- Reduced in e-transport chain in bacteria to active metabolite => DNA breaks
- Mammalian cells lack enzyme, thus not susceptible
- Anaerobic activity only(gram+ve and -ve)
Metronidazole
PKs?
- Good oral absorption
- VOD 0.85L/kg
- good tissue penetration includ. CNS
- Liver metabolism
- T1/2 6-8 hrs
Metronidazole
SEs?
DIs?
- peripheral neuropathies

- Inhibits alcohol dehydrogenase (avoid alcohol); nausea/vomiting
Folic acid Syn, inhibitors
Sulfonamides
Mech?
e.g sulfamethoxazole ususally in combo with trimethoprim

- inhibit folic acid syn from PABA.
- folic acid is needed in nucleoside production
- bacteriostatic!
Sulfanomides
PKs?
SEs?
- good oral absorption
- renal elimination, T1/2 10 hrs

Crystaluria, thrombocyto- and leukopenia, hepatitis