Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
99 Cards in this Set
- Front
- Back
|
Are Penicillins/B-Lactams bactericidal or bacteriostatic?
|
Bactericidal
|
|
|
Are Peniccilins/B-Lactams effecttive against gram (+) bacteria, gram (-) bacteria or both?
|
gram (+)
|
|
|
Which Penicillin drug has up to 1 week for its half life?
|
Benzathine Penicillin
|
|
|
Which Penicillin drug is excreted very rapidly, therefore must give around 3 doses/day to keep up its MIC?
|
Penicillin G
|
|
|
Which Penicillin drug has about a 24 hour half life?
|
Procain Penicillin
|
|
|
For the perfect drug, would it be beneficial for the LD50 to be high or low and/or the MIC/MBC to be high or low?
|
LD50 should be high
MIC/MBC should be low |
|
|
What are some characteristics of the perfect drug?
|
LD50 high, MIC/MBS low
bactericidal better- gets rid of it faster want drug to reach the target sit in the body w/ effective concentration broad vs narrow (more resistance with broad) lack of side effects: Therapetuci index: effective to toxic dose little resistance development |
|
|
When a bacteriostatic drug is given to a patient (ex tetracycline), what does the MIC line look like?
|
It is a flat line straight across: the bacteria just stops growing. Its slope stays the same
|
|
|
When a bactericidal drug is given to a patient (ex: penicillin), what does the MIC line look like?
|
The line will decrease its slope over the next few hours, bacteria are dieing
|
|
|
Which Penicillin is hydrolyzed by acid in the stomach, and which one is acid-stable?
|
Penicillin G is hydrolyzed by acid
Penicillin V is acid-stable |
|
|
How is Penicillin V made?
|
Phenoxyacetic acid is added to the medium of the mold producing penicillin
|
|
|
Can Penicillin G be given orally?
|
Yes because it is inexpensive, it just has to be given at larger doses
|
|
|
Penicillin G is given parenteral more often than orally because?
|
It is acid-labile, it is not resistance to acid. It will be hydrolyzed
|
|
|
Is Penicillin V given parenteral or orally and WHY?
|
Given orally because it is acid-stable/acid-resistant
|
|
|
Why is Penicillin V acid-stable?
|
Because it has an ether type link next to the Penicillin part of the drug. Penicillinases wont be able to cleave the ether link very easily
|
|
|
Is Penicillin S mainly for oral of IV injection and which salt form is it?
|
It is the K+ salt of the drug
mainly for IV injection |
|
|
Is Penicillin N resistant to Penicillinases?
|
NO
|
|
|
Why does Penicillin N have a prolonged type of action?
|
It has a good propellor (the amphoteric part on the end of the drug).
|
|
|
Is the amphoteric part of Penicillin N H2O soluble?
|
yes, highly H2O soluble
|
|
|
What part of Penicillin O makes it resistant?
|
The S (sulfur); no enzyme will cleave it
|
|
|
Which Penicillins/B-Lactams are Semi-Synthetic?
|
Cyclacillin, Dicloxacillin, Doktacillin, Nafcillin Sodium, Methicillin Sodium, Azlocillin
|
|
|
Which Semi-Synthetic Penicillin has the best protection for B-lactamases?
|
Methicillin Sodium
|
|
|
Are Dicloxacillin and Nafcillin Sodium resistant to Penicillinases?
|
YES
|
|
|
What does MRSA stand for?
|
Methicillin Resistant Staphylococcus Aureus
|
|
|
What is a B-Lactamase
|
It is a simple bacterial toxin that the bacteria creates to protect them against B-Lactam drug (Penicillinase same thing)
|
|
|
What doe Penicillins do to bacteria?
|
They inhibit cell wall synthesis
|
|
|
Are Penicillins effective against Gram (-) bacteria
|
Not really because their cell wall is hard to get through
|
|
|
What does the cell wall provide for the bacteria?
|
Provides strength and rigidity for the organism
|
|
|
What does the bacterial cell wall consist of?
|
polypeptide-polysaccharide: also known as peptidoglycan or murein
|
|
|
Where is the pentaglycine chain in Gram-positive bacteria?
|
in the cross-link
|
|
|
Where is the pentaglycine chain in Gram-negative bacteria?
|
Gram-negative lack the pentaglycine chain; instead there is a direct link between one tetrapeptide to the neighboring tetrapeptide
|
|
|
What do B-Lactam drugs attack in the cell wall of bacteria?
|
the pentaclycine cross-link
|
|
|
Do humans have molecules similar to peptidoglycan?
|
NO: why drugs wont attack our cells
|
|
|
Where are the peptidoglycan layers on gram-positive bacteria located?
|
On the top of the bacteria
|
|
|
Where are the peptidoglycan located on gram-negative bacteria located?
|
in between lipid bilayers of the membrane
|
|
|
What does transpeptidase do?
|
its a bacterial enzyme that cross-links the peptidoglycan chains to form rigid cell walls
|
|
|
What are PBP (Penicillin Binding Proteins)?
|
a group of proteins that are characterized by their affinity for and binding of penicillin; They are a normal constituent of many bacteria; Most B-lactam antibiotics will bind to these PBP of bacteria
|
|
|
Which functions are related to PBP 1a and 1b?
|
Peptidoglycan synthesis
cell wall elongation |
|
|
Which function is related to PBP 2?
|
maintenance of rod shape
|
|
|
Which function is related to PBP 3
|
Peptidoglycan synthesis
septum formation |
|
|
Which function is related to PBP 4,5,6?
|
control extent of x links
|
|
|
What part of the enzyme transpeptidase is similar in structure to B-lactam drugs?
|
the dipeptide D-Ala-D-Ala
|
|
|
What is the site of action of B-Lactam antibiotics?
|
The transpeptidase (muramoylpentapeptide carboxypeptidase)
|
|
|
What is the first step that B-Lactam drugs attach to bacteria?
|
They will first bind reversibly that brings the B-Lactam ring in close proximity with an ESSENTIAL SERINE RESIDUE OF ENZYME
|
|
|
What happens after the B-Lactam ring is in close proximity to the seine residue of the the enzyme?
|
Nucleophilic substitution then results in the formation of astable covalent bond between enzyme and the inhibitor; blocks the active site
|
|
|
What happens after the B-Lacatm ring substitution making the active site blocked?
|
The loss of activity of the enzyme leads to the formation of unstalbe cells walls and certainly leads to the death of dividing bacteria :)
|
|
|
When the B-Lacatam drug block the active site in the bacteria, will it be destroyed or can it go the the next bacteria?
|
It will be destroyed along with the transpeptidase
|
|
|
What is a superinfection?
|
Its a nonspecific side effect, such as overgrowth of the large intestine with Clostridium difficile (pseudomembranous colitis)
|
|
|
Is hypersensitiviety a common problem with B-Lactams?
|
Yes, it can be a serious problem
|
|
|
Were the early penicillin benign or did they have side effects?
|
benign
|
|
|
Is the MIC for B-lactamase positive Staph large?
|
Yes, because it is mutating every 7-days, want to kill it as much from the start
|
|
|
What is important to do to kill bacteria before induction?
|
Give a large initial dose
|
|
|
What are the Natural Penicillins?
|
Penicillin G and Penicillin V
|
|
|
Penicillin G is the same as
|
Benzylpenicillin
|
|
|
Penicillin V is the same as
|
Phenoxymethylpenicillin
|
|
|
What is the spectrum for natural penicillins?
|
- Gram positive organisms
- Gram positive anaerobes (NOT Bacteroides fragilis) - Spirochetes - Penicillin V NOT for serious infections use Penicillin G |
|
|
What are the Aminopenicillins?
|
Ampicillin
Amoxicillin Hetacillin |
|
|
What is the spectrum for Aminopenicillins?
|
- relatively broad Gram+ and Gram-
- NOT good for B. Fragilis - B-Lactamase sensitive |
|
|
What is often with Aminopenicillins when you give it to a patient?
|
Clavulanic acid or sulbactam
|
|
|
Is Clavulanic acid K salt form usually with Amoxicillin or Ampicillin?
|
Amoxicillin
|
|
|
Is Sulbactam usually with Amoxicillin or Ampicillin?
|
Ampicillin
|
|
|
What are Clavulanic Acid and Sulbactam
|
B-Lactamase Inhibitors
|
|
|
What are the B-Lactamase Resistant Penicillins (Antistaphylococcal penicillins)?
|
Methicillin (prototype), Cloxacillin, Dicloxacillin, Nafcillin, and Oxacillin
|
|
|
What are the dosage form of B-Lactamase resistant penicillins?
|
PO dose forms, some IV/IM, some intramammary
|
|
|
What is the spectrum for B-Lactamase resistant penicillins?
|
Primarily for B-Lactamase producing staphylococcal infections
- other drugs generally preferred otherwise |
|
|
What are the Antipseudomonal Penicillins?
|
Azlocillin, Carbenicillin, Mezlocillin, Piperacillin, Ticarcillin
|
|
|
What are the dosage form of Antipseudomonal penicillins?
|
IV/IM
indanyl form of Carbenicillin -PO |
|
|
What is the spectrum of Antipseudomonal penicillins?
|
Pseudomonas aeruginosa and other problem gram negative bacteria
- B-lactamase sensitive - other penicillins better for typical G+ organisms |
|
|
Are Clavulanic Acid and Sulbactam beta-lactamase inhibitors irreversible inhibitors or reversible inhibitors?
|
irreversible inhibitors
|
|
|
Is Pen G, Clavulanic acid, or the combination of Pen G and Clavulanic Acid protected?
|
Only the combination of Penicillin G and Clavulanic Acid
|
|
|
Which Penicillin have high protein binding?
|
Dicloxacillin & relatives (97)%
|
|
|
Is Penicillin Distribution inside bone good or poor?
|
Good
|
|
|
Where is Penicillin Distribution poor?
|
eyes, inside cells, mammary glands, CNS
|
|
|
Can you treat meningitis with a Penicillin?
|
NO
|
|
|
What is the average half-life for Penicillins?
|
SHORT- 0.4-1.5h
|
|
|
How does impaired renal function effect penicillin half-life
|
It increases the half life EXAMPLE
Ampicillin goes from 1-1.3h to 10-15h impaired PenG goes from 0.5-0.7h to 2.5-10h imparied |
|
|
What is the percentage of of penicillin that is eliminated renally?
|
80-90%
|
|
|
How can a potassium salt form of a drug be dangerous?
|
It can lead to hyperkalemia, which is bad especially for people on B-Blockers
|
|
|
Is Anaphylactic shock an adverse effect from Penicillins?
|
YES- kills 300 humans/year
|
|
|
Does allergy incidence increase or decrease in viral infections?
|
increase
|
|
|
Are semisynthetic penicillins produced by a form of fermentation?
|
NO
|
|
|
What is common and non common among Semisynthetic penicillins?
|
same common nucleus; where side groups around the nucleus change
|
|
|
Are Semisynthetic penicillins resistant to penicillinases?
|
NO
|
|
|
Of the Semisynthetic Penicillins, which as a greater activity
|
Carboxypenicillins
|
|
|
What are some of the semisynthetic penicillins?
|
methicillin, Oxacillin, Carbenicillin, Ampicillin
|
|
|
What are the disadvantages of Penicillin/B-Lactam drug?
|
B-Lactamase will cleave B-lactam ring and they don't have a narrow spectrum of activity
|
|
|
What practices lead to resistance among bacteria?
|
1. overuse or misuse of antibiotics
2. patient demand of viral infections 3. use of antibiotics by immunosuppressed patients 4. long term, low dose treatment for acne 5. noncompliance 6. animal feed 7. world travel |
|
|
The effect of two drugs given together is greater than the effect of either alone
|
Synergism
|
|
|
What is an example of synergism?
|
Penicillin & Streptomycin
|
|
|
What is an example of antagonism?
|
Penicillin & Tetracyclines
|
|
|
How are aminoglycosides and penicillins synergistic?
|
Penicillin will destroy the cell wall of the bacteria and then the Aminoglycoside will enter the cell where the cell wall was destroyed
|
|
|
What drug is Penicillinase-resistant parenteral?
|
Methicillin
|
|
|
What drugs are penicillinase-resistant oral?
|
Oxacilling, Cloxacillin, and Dicloxacillin
|
|
|
What drugs are penicillnase-sensitive parenteral broad-Spectrum?
|
Carbenicillin, Carindacillin, Ticarcillin, Azlocilling, Mexlocillin, Piperacillin
|
|
|
What drugs are Penicillinase-sensitive oral and broad spectrum?
|
ampicillin and amoxicillin
|
|
|
Do more bacteria produce B-Lactamases or penicillinases?
|
B-lactamases
|
|
|
Under a basic environment what will be the primary decomposition product of penicillin?
|
Penilloic Acid
|
|
|
What are the three decomposition products of penicillin in an acidic environment?
|
First are Penicillamine and Penaldic Acid, then Penillic Acid is formed
|
|
|
What B-Lactamase inhibitors is given IV with Ampicillin and Methicillin?
|
Tazobactam sodium
|
