Beta-Lactams Flashcards
Natural penicillin (penicillin G/V) is effective against treponema pallidum and therefore is the drug of choice for treating ________.
Syphilis
Nearly all available beta-lactams lack activity against MRSA. Among the available beta-lactams, only the fifth generation cephalosporin _____ has anti-MRSA activity.
Ceftaroline
All beta-lactams lack activity against atypical organisms such as _____ and _______, so add another agent if you are concerned about these bugs, as in cases of community-acquired pneumonia.
Mycoplasma pneumoniae and chlamoydophila pneumoniae
Penicillins, ______, and _______ are all beta-lactams.
Penicillins, cephalosporins, and carbapenems
________ can result from high doses of any beta-lactams.
Seizures
All beta-lactams can cause hypersensitivity reactions, ranging from mild rashes to drug fever to _____ to anaphylaxis.
acute interstitial nephritis (AIN)
True or False: Penicillins have very short half-lives (< 2 hours) and must be dosed multiple times per day. The half-lives of most of them are prolonged in the presence of renal dysfunction.
True
Many penicillins are relatively poorly absorbed, even those available as oral formulations. This can lead to _____ when oral therapy is needed.
Diarrhea
True or False: All beta-lactams inhibit cross-linking of peptidoglycan in the cell wall, leading to autolysis and cell death.
True
Natural penicillins (Penicillin G and V) have good activity against _____ and ______, and moderate activity against enterococci.
Treponema palladium and most streptococci, including Streptococcus pneumoniae
Natural penicillins have a very short half-life and must be dosed frequently or given by continuous infusion. Long-acting depot formulations (______, _______) are available for intramuscular administration.
Procaine, benzathine
Penicillin __ is the oral form of penicillin __.
A. V, G
B, G, V
A. V, G
True or False: Penicillin is a good empiric choice for most infections.
False! Because of resistance, penicillin is a poor empiric choice for most infections.
Anti-staphylococcal Penicillins include which 3 drugs that are still used?
Nafcillin
Oxacillin
Dicloxacillin
Anti-staphylococcal Penicillins have good activity against which 2 of the following? A. MSSA B. MRSA C. Streptococci D. Enterococci
MSSA and streptococci
Anti staphylococcal penicillins (Nafcillin, Oxacillin, Dicloxacillin) have a short half-life and must be dosed frequently. This presents a problem, because they cause this adverse effect.
Phlebitis
True or False: Beta-lactams kill staphylococci more quickly than vancomycin.
True! So patients with MSSA infections who lack serious beta-lactam allergies should be switched to beta-lactams, such as antistaphylococcal penicillins.
True or False: Anti-staphylococcal penicillins (Nafcillin, Oxacillin, Dicloxacillin) are interchangeable therapeutically.
True
Which 2 agents fall under the class of aminopenicillins?
Amoxicillin, ampicillin
True or False: Aminopenicillins are more water- soluble and pass through porin channels in the cell wall of some Gram-negative organisms.
True
True or False: Aminopenicillins are not susceptible to beta-lactamases.
False! They are susceptible to beta-lactamases, so resistance to them has become fairly common in many regions of the world.
Aminopenicillins (Amoxicillin and Ampicillin) have good coverage against which 2 of the following? A. MSSA B. MRSA C. Streptococci D. Enterococci
C. Streptococci
D. Enterococci
True or False: Unlike other beta-lactams, aminopenicillins have a low incidence of diarrhea when given orally/
FALSE! Aminopenicillins have a high incidence of diarrhea when given orally.
Which is a better choice of the aminopenicillins: Amoxicillin or ampicillin
Amoxicillin. It is more bioavailable, better tolerated, and administered less frequently.
Antipseudomonal penicillins are not available in oral form. Which is the most commonly used IV form? A. Piperacillin B. Mezlocillin C. Carbenicillin D. Ticarcillin
A. Piperacillin
True or False: Pseudomonas aeruginosa is a common nosocomial pathogen.
True
Antipseudomonal penicillins (Piperacillin and Ticarcillin) have good coverage against which 3 of the following? A. MSSA B. MRSA C. Streptococci D. Enterococci E. Pseudomonas aeruginosa
C. Streptococci
D. Enterococci
E. Pseudomonas aeruginosa
True or False: First-generation cephalosporins are the most commonly used class of antibiotics in the hospital. Why? They are used immediately prior to surgery to prevent surgical site infections. Their spectrum of activity, inexpensive cost, and low incidence of adverse effects make them ideal for this purpose. For the same reasons, they are useful in treating skin and skin structure infections as well.
True
Surgical prophylaxis is the most common indication for ___-generation cephalosporins.
First generation cephalosporins
List some first generation cephalosporins.
Cefazolin, cephalexin, cefadroxil
First-generation cephalosporins are good alternatives to _______ penicillins. They cause less phlebitis and are infused less frequently. Unlike antistaphylococcal penicillins, however, they do not cross the blood–brain barrier and should not be used in central nervous system (CNS) infections.
Antistaphylococcal penicillins (Nafcillin, oxacillin, dicloxacillin)
Cephalosporins with the N-methylthiotetrazole (MTT) side chain—cefamandole, cefmetazole, and \_\_\_\_ —can inhibit vitamin K production and prolong bleeding. These MTT cephalosporins can also cause a disulfiram-like reaction when co-administered with ethanol. A. Cefuroxime B. Cefoxitin C. Cefotetan D. Cefprozil
C. Cefotetan
True or False: First generation cephalosporins do not cross the BBB.
True
True or False: Second generation cephalosporins do not cross the BBB well enough to be used for CNS infections.
True
Cephamycins are grouped with the second- generation cephalosporins because they have similar activity, with one important exception: anaerobes. Cephamycins have activity against many anaerobes in the GI tract, and cefoxitin and cefotetan are often used for surgical prophylaxis in abdominal surgery. All of the following are cephamycins EXCEPT: A. Cefoxitin B. Cefprozil C. Cefotetan D. Cefmetazole
B. Cefprozil
True or False: Third-generation cephalosporins have greater Gram-negative activity than the first- and second- generation drugs.
True
Which of the following 3rd generation cephalosporin has pseudomonas coverage? A. Ceftriaxone B. Cefotaxime C. Ceftazidime D. Cefdinir E. Cefpodoxime
C. Ceftazidime
Which of the following 3rd generation cephalosporin has the N-methylthiotetrazole (MTT) side chain, which can inhibit vitamin K production and prolong bleeding. MTT cephalosporins can also cause a disulfiram-like reaction when co-administered with ethanol. A. Ceftriaxone B. Cefotaxime C. Ceftazidime D. Cefdinir E. Cefpodoxime
E. Cefpodoxime
True or False: Ceftazidime has pseudomonas coverage as well as gram positive broad spectrum coverage.
FALSE! Ceftazidime is the exception to the spectrum of activity rule for third-generation agents. Unlike the others, it is antipseudomonal and lacks clinically useful activity against Gram-positive organisms.
Which 3rd generation cephalosporin is the drug of choice for gonorrhea? A. Ceftriaxone B. Cefotaxime C. Ceftazidime D. Cefdinir E. Cefpodoxime
A. Ceftriaxone
True or False: 3rd generation cephalosporins do not cross the BBB.
FALSE! Ceftriaxone, cefotaxime, and ceftazidime cross the blood–brain barrier effectively and are useful for the treatment of CNS infections.
\_\_\_\_\_\_\_\_ has two problems that make its use in neonates problematic: it interacts with calcium- containing medications to form crystals that can precipitate in the lungs and kidneys, which has led to fatalities, and it can also lead to biliary sludging with resultant hyperbilirubinemia. Avoid it— cefotaxime is a safer drug for these young patients. A. Ceftriaxone B. Cefotaxime C. Ceftazidime D. Cefdinir E. Cefpodoxime
A. Ceftriaxone
\_\_\_\_ is a 3rd generation cephalosporin that has the characteristic of having dual modes of elimination via both renal and biliary excretion. It does not need to be adjusted for renal dysfunction, but it does effectively treat urinary tract infections. A. Ceftriaxone B. Cefotaxime C. Ceftazidime D. Cefdinir E. Cefpodoxime
A. Ceftriaxone
The only 4th generation cephalosporin is called ______.
Cefepime
True or False: Cefepime is the broadest-spectrum cephalosporin, with activity against both Gram-negative organisms, including Pseudomonas, and Gram-positive organisms.
True
True or False: Cefepime is a good choice for community acquired infections, but is overkill for nosocomial infections.
FALSE! Cefepime is used primarily for nosocomial infections. Although it is indicated for infections of the urinary tract and lower respiratory tract, it is overkill for most community-acquired sources of these infections.
Which of the following cephalosporins is a better choice for febrile neutropenia?
A. Ceftazidime
B. Cefepime
For monotherapy of febrile neutropenia, cefepime is a better choice than ceftazidime because of its better Gram-positive activity. It may also induce less resistance in GNRs than third-generation cephalosporins, but it is still not a good drug to overuse.
The only 5th generation cephalosporin is called ______.
Ceftaroline
This is the only cephalosporin that has anti-MRSA activity.
Ceftaroline
True or False: Unlike other cephalosporins, ceftaroline also has modest activity against Enterococcus faecalis (but not Enterococcus faecium).
True
Ceftazidime shares the same spectrum of activity as this monobactam.
Aztreonam
What sets aztreonam apart from other beta-lactams (aside from the fact that it is the only monobactam)?
Aztreonam’s quirk is that it seems to be safe to administer to patients with allergies to other beta-lactams, except patients who have a specific allergy to ceftazidime. This cross-reactivity seems to be a result of the fact that ceftazidime and aztreonam share an identical side chain.
Why is Cilastatin always administered with imipenem?
Imipenem is metabolized in the kidney to a nephrotoxic product. Cilastatin blocks the renal dehydropeptidase that catalyzes this reaction and prevents this metabolism from occurring. It is always co-administered with imipenem for this reason.
Which carbapenem is more likely to cause seizures? A. Imipenem B. Meropenem C. Ertapenem D. Doripenem
A. Imipenem
Which carbapenem is considered an exception because of its lack of activity against pseudomonas and acinetobacter, which other carbapenems have good activity against? A. Imipenem B. Meropenem C. Ertapenem D. Doripenem
C. Ertapenem
