Antibiotics Flashcards
Name the 4 types of Penicillins
- Natural Penicillins
- Aminopenicillins
- Penicillinase-resistant Penicillins
- Extended spectrum Penicllins
Name the 3 Natural Penicillins
- Pen G
- Pen G Procaine
- Pen B
Name the 2 Aminopenicillins
- Amoxicillin
2. Ampicilllin
Name the 4 Penicillinase-resistant Penicillins
- Cloxicililn
- Oxicillin
- Nafcillin
- Mehtycillin
Name the 3 extended spectrum Penicillins
- Tigercillin
- Pepercillin
- Azocillin
All Penicillins contain a nucleus composed of a _-______ ring
B-Lactam
What is the MOA of Natural Penicillins?
They exert bactericidal action against penicillin-susceptible microorganisms during the stage of active replication
-interfere w/bacterial cell wall synthesis by reacting w/>1 Penicillin binding protein
Bacteria produce how many different types of Penicillin-Binding proteins?
4
How does Penicillin resistance happen?
Production of B-Lactamase; an enzyme intermediate that destroys Penicillin activity.
True/False: Metabolism and disposition vary significantly among Pencillins & w/age of pt.
True
Penicillins Are/Are not well absorbed from the GI tract?
Are NOT (except Pen-V)
Which Penicillin is used perenterally?
Pen G
Penicillins bind to proteins, mainly which one?
Albumin
Do Penicillins penetrate the CSF well?
No
Penicillin acts synergistically with what other meds?
Against many strains of?
Gentamycin & Tobramycin
Enterococci
Name the types (general) of bacteria Penicillins work against?
Gram + cocci Gram + bacilli (listeria) Gram - Bacteria Anaerobic Spirochetes
Clinical uses of Penicillins are effective to treat?
Group A streptococci Group B streptococci Meningococci Actinomyces T. Pallidium Also: susceptible Streptococcus pneumoniae, Enterococci, & Gonococci
What Penicilin can be used for primary, secondary, early or late latent Syphilis (except for neuro-syphylis)?
IM Benzathine PCN
What Penicilins are used for Congenital Syphilis?
Pen G or Procaine Pen
What is considered the major s/e of Penicillins?
Severe/fatal anaphylaxis
0.01-0.05 % of people receiving PCN’s
Name the Adverse Reactions of Pencillins
- Allergic reactions
- Hematologic Toxicity (coombs + anemia, leukopenia, thrombocytopenia)
- Sodium Overload
- Hypokalemia
- Neurologic toxicity/seizures (following massive doses)
Pts given continuous IV tx w/PenG/K in high doesage may suffer?
Severe and fatal K+ poisoning..especially w/renal insufficiency
Concurrent administration of bacteriostatic Abx may ________ the bactericidal effects of PCN’s by slowing?
Decrease
Slowing rate of bacterial growth
Probenecid blocks renal tubular secretion of?
PCN’s (so may have increased blood levels w/concurrent admin)
Aminopenicillins contain a free ______ group at the Alpha position on the B-Lactam ring of the PCN nucleus–>incrasing ability to penetrate _____ _________ organisms
Amino
Gram Negative
What is the MOA of Aminopenicillins?
Exert bactericidal action against penicillin-susceptible microorganisms during the stage of active replication
How is Resistance to Aminopenicillins achieved?
They are inactivated by the B-Lactamases produced by Gram + or Gram - bacteria
Aminopenicillins achieve therapeutic levels in most body fluids including:
CSF, Pelural, Joint, Peritoneal
Aminopenicillins are cleared by?
Kidneys
Which Aminopenicillin has better absorption/bioavailability?
Amoxicillin–the preferred PO aminopenicillin. Absorption is not affected by food.
What is the spectrum of Aminopenicillins?
Increased efficacy against most Enterococci, L. Monocytogenes, H. Influenza, N. Gonorrhea
What strains are resistant to Aminopenicillins?
Some E-Coli, Shigella, Salmonella
What Aminopenicillin is drug of choice for Otitis media and Lyme’s dz?
Amoxicillin
What Aminopenicillin is widely used for septic neonates?
Why?
Ampicillin
D/t it’s coverage against Listeria
What are the adverse effects of Aminopenicillins?
Hypersensitivity reactions
Penicillinase-Resistant Penicillins are what derivitives?
Semisynthetic Penicillin Derivitives
What is the MOA of Penicillinase-Resistant PCN’s?
- Bind to Penicillin Binding Proteins and prevent cell wall synthesis
- Resistant to action of bacterial PCN-ases; prevents opening of B-Lactam ring
What is the Spectrum of PCN-ase Resistant PCN’s?
Effective against B-Lactamase-producing isolates of Staphylcoccus Aureus & Coagulase-Negative Stahpylococci
True/False: Ater Oral admin, PCN-ase resistant PCN’s are adversely affected by food?
How are they excreted?
True
Urinary/Biliary excretion
What are PCN-ase resistant PCN’s used for?
Empiric tx of skin and skin-structure infections, bone, joit infections where Staphylococcus Aureus is likely
What are the Adverse effects of PCN-ase resistant PCN’s?
Interstitial Nephritis (Methicillin) -C.M.'s= Fever, rash, eosinophilia, proteinuria, hematuria
Choestasis
- Usually w/o Jaundice
- Reported w/Oxicillin use (usually Liver enzymes return to normal after D/C use)
With what 2 drugs might you have adverse effects when giving PCN-ase resistant PCN’s?
Warfarin
Cyclosporine
Extended spectrum Penicillins have Broader/Narrower spectrum than both Natural and Aminopenicillins.
Broader
Are Extended-spectrum PCN’s right for tx systemic infections?
Why/why not?
No
Serum and tissue levels are not adequate
What are Extended-spectrum PCN’s good for?
Is there good CSF penetration?
Primary elimination is?
UTI’s (uncomplicated)
No
Renal
What are the clinical indications of extended-spectrum PCN’s?
Effective: gram - organisms
In combo w/Gent, Gram - bacilli
Generally used w/B-Lactamase inhibitor
What are the adverse effects of the extended-spectrum PCN’s?
Hypersensitivity reactions
Plt dysfunction–prolonged bldg times
Inhibition of Plt aggregation
Extended-spectrum PCN’s have drug interactions with what 3 meds?
- Warfarin (decreases effect of it)
- Piperacillin (potentiates action of non-depolarizing blocking agents)
- Aminoglycosides (causes degradation of the aminoglycoside–why they are used in solution and separated by 30 min)
Name the MOA of Celphalosporins
- Possesses a B-Lactam ring
- Interfere w/synthesis of peptidoglycan in the bacterial wall
- Bind to and inactivate Penicillin Binding Proteins (enzymes for synthesis of bacterial cell wall)
How many classifications of Cephalosporins are there?
4
1st-4th
The first classification of Cephalosporin is good against?
- Most Gram + cocci (excluding MRSA, Eterococci, Staph Epidermis)
- Modest activity against many Gram - bacteria
The second classification of Cephalosporin has increased activity against?
- Gram - bacteria–but less so than 3rd generation
- Variable activity against Gram + cocci
- Improved activity against H-influenza, Gonnorhea, & N. Menengitits
The 3rd classification of Cephalosporins are more active against?
Enterobacter Cinae, B-Lactamase producing strains & Staph Pneumoniae.
The 4th classification of Cephalosporins have increased spectrum activity than 3rd generation and are more active against?
H-Influenza, Nisseria species, Psuedomonas, Gram + cocci, Staph Aureus, Staph Pneumoniae, other Stroptococci
The classifications of Cephalosporins reflects increasing __________ of higher generations to various bacterial __-_______.
Stability
B-Lactamases
None of the Cephalosporins are effective against:
MRSA
Enterococci
Listeria
Clostridium
There are 3 mechanisms of resistance to Cephalosporins:
- Inactivation by B-Lactamases
- Alterations of Penicillin-binding Proteins
- Alteration of Bacterial Permeability
True/False: there is good penetration into the tissues and fluid compartments including CSF of Cephalosporins
True
First and Second generation Cephalosporins are used for?
Skin and Respiratory tract infections
Third generation Cephalosporins are used for?
Empiric tx
Fourth generation Cephalosporins are used for?
Febrile Neutropenia and Nosocomial infections
Name some adverse effects of Cephalosporins
- Maculopapular rash, drug fever, positive Coombs
- Anaphylactic rxn varies 0.0001-0.1%
- Renal insufficiency may need doseage adjustments
What are the advantages of Aminoglycosides? (4)
- Effective against Gram - organisms
- Synergism w/B-Lactam Abx
- Limited bacterial resistance
- Low-cost
Successful use of Aminoglycosides has been complicated by what 2 side-effects in a significant number of treated pts?
Nephrotoxicity
Ototoxicity
What is the MOA of Aminoglycosides?
- Alter the integrity of the bacterial wall membrane by disturbing protein synthesis.
- Binds to the bacterial cell membrane and may play role in rapid bacterial cell death.
What are the indications of Aminoglycoside use?
- Tx of serious Gram - infections caused by Enteric Bacilli
- Act synergistically w/Cephalosporins & Penicillins
- Used in Combo w/Vanco for S.Aureus (both Methicillin-Sensitive and Methicillin-Resistant)
After PCN’s, what are the most commonly used meds in the NICU?
Aminoglycosides
In general, emergence of an Aminoglycoside resistant strain (other than Coag. Neg Streptococci) is relatively?
Slow (a definite advantage over 3rd gen Cephalosporins)
What are the indications of Aminoglycosides? (2)
- Septicemia
2. UTI
How do Aminoglycosides tx Septicemia?
- Gram - bacteria: E-Coli, Klebsiella, Enterobacter, Pseudomonas
- Synergistic w/B-Lactam Abx in tx GBS and Coag neg. Staph infections
- Important in initial empiric tx of neonatal Septicemia
W/UTI, how do Aminoglycosides work?
They are excreted by glomerular filtration and partly actively reabsorbed–>high tissue and urine concentrations
True/False: then known s/e of Ototoxicity and Nephrotoxicity a/w Aminoglycoside use can happen months later.
True
-Studies show it’s r/t high trough levels (high renal accumulation). Probably r/t total dose and duration rather than serum concentrations.
Aminoglycoside dosing has been revised toward?
Larger doses in extended intervals
Dosage and intervals of Aminoglycosides are dependent on?
GA & PNA
Routine therapeutic drug monitoring is usually around which doses?
3rd-4th
True/False: Complications are common in courses shorter than 7 days.
False, this is rare.
Name the most common Glycopeptide in NICU.
Vancomycin
Vancomycin is used for?
Gram + infections
Vancomycin can be inactivated by?
Heparin in high concentrations
What is the MOA of Vanco?
Bactericidal activity is based on the inhibition of bacterial cell wall synthesis
Resistance to Vanco is seen in?
Enterococci, S. Aureus, S. Epidermis
True/False: there is increasing concerns of Vanco intermediate resistant strain of Staph Aureus (VIRSA).
Why/why not?
True
D/t thickened & aggregated cell walls
Infection w/VIRSA is a/w?
Tx failure of Vanco
A mechanical factor in clinical resistance of S. Aureus infections to Vanco is production of what?
Biofilm of bacteria, shielding it from the Antibiotic
What are the indications for use of Vanco?
Methicillin-Resistant strains of Staphylococcal infections
Vanco is widely used for empiric tx of? (2)
- Line-related infections
2. Late-Onset Setpicemia
Vanco is eliminated via?
Glomerular filtration
True/False: Vanco cannot be relied upon to adequately tx Gram + meningitis alone.
True
What has the ability to alter the pharmacokinetics of Vanco?
GA, PNA, Post-conceptual age (this has a stronger influence on Vanco pharmacokinetics than GA or PNA)
Toxicity of Vanco includes:
- Infusion-related effects (Red-man’s syndrome= Histamine mediated rash of puritis, flushing, tingling, tachycardia, shock)
- Drug-Related effects (Thrombocytopenia, Neutropenia, Eosinophilia, Cihlls, Fever, Rash, Nephrotoxicity, Ototoxicity)
Redman’s syndrome is r/t what?
The rate of infusion (< 1 hr)
The incidence of s/e’s w/Vanco admin decreased significantly when what happened?
Impurities were removed from early preparations in the 1960’s.
