Beta-Lactam Antibiotics Flashcards by Kwame Awuku

List important components to the structure of the penicillin. 3 things

4 membered nitrogen containing compound

sulfur containing 5 membered ring

then R group coming off of the amine(where you can make substitutions

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what is so significant about the R-group on the Beta lactam ring and where is the site of hydrolysis by acid or B-lactamase

R-group determines stability to acid or B-lactamase hydrolysis

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what is the structure and the list some components of the cephalosporin.

Six membered sulfur containing ring

4 membered nitro containing ring

R group in two locations

off of the sulfur containing ring
of of the nitro group

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What is the structure and list some components about Carbapenems

5 membered ring that is not sulfur containing; sulfur instead comes off of the ring(formamidine)

4 membered nitro containing ring

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what is the structure and list the components of the monobactems

no other ring coming off of the 4 membered nitro containing ring

sulfate and nitro group coming off the 4 membered nitro containing ring

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what are the 4 types of penicillins?

Penicillin G (Pen V is the oral prep)

Acid-stable or Antistaphylococcal (isoxazolyl)(ox, clox and icloxacillin, methicillin)

Extended-Spectrum (amoxicillin, ampicillin)

Antipseudomonal or ureido penicillins (piperacillin)

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list the different types of acid stable or antistaphylococcal penicillins

methicillin, oxacillin, cloxacillin, dicloxacillin

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what are the different types of extended spectrum penicillin

amoxicillin and ampicillin

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what are the types of antipseudomonal or ureido penicillin

piperacillin, carbenicillin, and ticarcillin

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what are some organisms that penicillin G or the oral type penicillin V is used against?

use it against gram + bacteria

use it against non b-lactamase staph and strep

obligate anaerobes like actinomyces and clostridia

Treponium palidum(syphillis)

meningococcal and used to be good for neiserria gonorhea

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what do you want to use acid stable or antistaphylococcal penicillins (meth-, oxa-, cloxa-dicloxacillin) against

against penicillanase producing staphylococcus aureus

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what is extended spectrum (ampicillin and omaxicillin) used against

use against gram neg p mirabilis, H influenzae, E.coli, listeria moncytogens, salmonella shigella, and enterococcus faecalis

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what is the antipseydomonal or ureido penicillins used against

pseudomonas aeruginosa, K pneumonia, serratia marcescens, and gram - rods

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in peptidoglycan synthesis, what strands need to be crosslinked

NAM(N-acetyl muramic acid) and NAG(N-acetyl glucosamine) need to be crosslinked

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What is the mechanism of B-lactams

All of the β-lactams interfere with this process of crosslinking during peptidoglycan synthesis. This causes faulty linkage in the peptidoglycan and thus the structural integrity of the bacterial cell wall is compromised and so ultimately the bacterium die

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what are the requirements for B-lactams to be efficient and work properly

Growing cultures are required
Peptidoglycan cell wall producing bacteria
Irreversibly inhibit the transpeptidation reaction
Osmotic pressure causes the bacterial cell to burst-bactericidal
activate autolysins in some organisms

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what are autolysins

The β-lactams activate autolysins in bacteria. Many organisms including bacteria are most vulnerable when they are dividing. So the autolysins are there for use by the bacteria so that they can open up their cell walls and then reseal them during cell division. So β-lactams can interfere with this process by activating autolysins and this contributes to their bactericidal activity.

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list the mechanisms of resistance for B-lactams

B-lactamse breaks B-lactam ring (chromosomal or plasmid)
Reduced binding to penicillin binding proteins; methicillin resistant staph aureus
Decreased access to gram neg organisms via down regulationof porins
Increased efflux pumps found in some gram neg organism

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a few gram negative bacteria can confer resistance to B-lactams by

down regulation of porins: Gram negative bacteria require pores in their outer membrane so that things can get in and out but they can modify the size to inhibit the entry of antibiotics like β-lactam.

efflux pumps:A few Gram negative organisms have very active efflux pumps. So in this case the β-lactam gets into the periplasmic space between the inner membrane and the outer membrane but it can’t be concentrated at a high enough level to perform its actions effectively

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if patient is suspected of having meningitis what penicillin would you use

extended spectrum penicilin; ampicillin or amoxicillin against listeria monocytonges

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what are the orally active penicillins

Pen V, ampicillin, amoxicillin, and all of the isoxozolyl

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which ones are given IV

pen G, piperacillin, and methicillin

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what is the definition of time dependent killing

plasma levels should be greater than the MIC for at least 70% of every 24 hrs…particularly gram - penicillin exhibits this

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explain penicillins metabolism and its renal excretion if any

excreted via urine unchanged because there is no metabolism also it can be pumped(proximal tubule) and filtered through the renal system.

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can penicillin penetrate the CSF

no but it can during times of inflammation early during its onset before the meninges have healed

what are the adverse effects of penicillins

rashes and anaphylaxis due to hypersensitivity ampillicin can cause a maculopapular rash because of chemical reaction in skin not allergic seizures with high doses due to penicillin interfering with GABA: neurotoxicity nephritis diarrhea because normal gut flora disrupted platelet dysfunction false positive for urinary glucose cation toxicity

what side effect does methicillin cause

nephritis

what side effect does ticarcillin cause

platelet dysfunction and cation toxicity

which penicillins cause cation toxicity

ampicillin, ticarcillin, and piperacillin

what is augmentin composed of and what is the side effect.

Augmentin is composed of amoxicillin and clavulanic acid(which is a beta lactamase inhibitor). The combination will effectively deal with penicillinase producing organism. However it can also cause a false positive for urinary glucose.

what are the different adjunct medications given with penicillin

Probenecid and penicillin Augmentin: (Clavulanic acid and amoxicillin)

why do we give probenecid with penicillin

because it will decrease the rate of excretion of the penicillin by acting at the organic acid pump in the proximal tubule of the kidney, making penicillin rely only on glomerular filteration for its excretional methods

what are the three different types of beta lactamase inhibitors?

1. Clavulanic acid 2. Tazobactam 3. Sulbactam

The mechanism of action, resistance, pharmacokinetics and adverse effects is similar to penicillin for cephalosporins except for what?

1. Third generation cephalosporins are more resistant to beta lactamases 2. There is a disulfiram-like effect when taken with alcohol

what is the structure of cephalosporins

What are the first generation cephalosporins

Cafazolin

What are the second generation cephalosporins

1. cefamandole 2. cefonicid 3. cefotetan

what are the third generation cephalosporins

1. Cerfoperzone 2. Ceftriaxone 3. Cefixime 4. Ceftazidime

what are the fourth generation?

Cefepime

Which cephalosporins cause the disulfiram-like effect (Hypoprothrombinemia)? and what is this effect?

2nd generation cefamandole, cefotetan, cefonicid and 3rd generation cefoperazone when some cephalosporins are taken with alcohol, you have a very serious adverse reaction to the drug. There’s changes in blood pressure, sweating, nausea, and vomiting. This occurs because if you drink alcohol and take that particular cephalosporin at the same time, you wind up with a lot of acetaldehyde which is a toxic compound.

specifically how does second generation cefamandole play in the disulrifam like effect

has a tetra imidazole sulfur-containing entity and this is the part of the drug that inhibits acetaldehyde dehydrogenase. Acetaldehyde dehydrogenase normally converts acetaldehyde into acetic acid

what is the spectrum of treatment from the 1st generation cephalosporins

mostly against gram + including the anaerobic streptococci but also gram - PEcK

what is the spectrum of treatment for 2nd generation cephalosporins

same as first gram positive and negative but with the addition of h. influenzae and used to treat sinustis, otitis, and pneumonia

what is third generation cephalosporins used against

Efective against gram-negative bacteria and used to treat serious gra-negative infections

specifically the third generation cephalosporin ceftazidime is used to treat

pseudomonal

fourth generation is used to

treat gram + and negative and serious gram-negative infections like meningitis, pseudomonas, enterobacter infections

which cephalosporin would you use to treat gonorrhea

ceftriaxone and cefixime

cefixime is taken how

orally

Meningitis due to pneumococci and meningococci and h influenzae but not listeria monocytogenes is treated by

3rd generation cephalosporins

what would you use for empiric therapy of sepsis of unknown origin in both immunocompetent and immunocompromised hosts

3rd generation cephalosporins

what are the four different types of carbapanems

imipenem, meropenem, doripenem, dertapenem

2nd generation have effects similar to

amoxicillin and ampicillin because they go against h. influenza and ecoli

3rd generation are given

parenterally thats why they are given in the hospital

. These drugs are usually reserved for a seriously ill patient where you don’t know what the etiological agent for the infection is yet. If you don’t treat the patient, there will be serious sequelae and even death. So you treat the patient

4th generation

carbapanems are given and can enter

parenterally and CSF

carbapenems are effective against

gram +, Gram _ aerobic and anerobic cocci and bacilli

carbapenems are wide spectrum and can be used

in treatment of hospital acquired resistant infections monotherapy for septicemia, neutropenic fever, intra-abdominal, lower respiratory tract, genitourinary, gynecological, skin and soft tissue, and skin and bone infections in patients who cannot tolerate a cephalosporin

if i am a patient who is prescribed cefazolin for bone infection but cannot take it because of toleration

you can take a carabapenem

what are the adverse effects

NVD, skin rashes, infusion site reactions; imipenem is convulsant at high doses(prolly cuz of CSF)

what type of carbapenem is used to treat bacterial meningitis

meropenem

monotherapy for septicemia, neutropenic fever, intra-abdominal, lower respiratory tract, genitourinary, gynecological, skin and soft tissue, and skin and bone infections in patients are treated with

Carabapenem

What is the only monobactam

Aztreonam

what drug spectrum is similar to aztreonam

aminoglycosides

aztreonam targets

gram negative aerobic bacteria

aztreonam works against

gram-negative rods(Klebsiella, pseudomons, serratia). it has no activity against gram-positive bugs or anaerobes

adverse effects of aztreonam

injection site reactions; pain

the aztreonam is fitered and secreted by

the kidney

aztreonam can be used as an alternative to

aminoglycosides, penicillins and cephalosporins

summary for aztreonam

Is a part of the monobactem B-Lactams - used to treat aerobic gram negative bacterial infections - It is not effective against gram positive or anaerobes - Given parenterally to patients; pain associated with the injection - This drug also penetrates well into the CSF without inflammation - Used as an alternative to aminoglycosides, penicillins, or cephalosporins