Antibiotics - notes Flashcards
What are the different antibiotic classes that are cell wall inhibitors?
- Beta-lactams
- lipoglycoproteins
- vancomycin
What are the different drugs included in beta-lactams?
- penicillin
- cephalosporins
- monobactams
- carbapenems
- beta-lactamase inhibitor compounds
- What are the drugs in the natural penicillin group?
- What are their routes of administration?
- What is their spectrum/coverage?
- do they cover gram + or gram -?
penicillin G
- IV/IM
- narrow spectrum
- gram +
penicillin V
- oral (more stable)
- narrow spectrum
- gram +
- What is the drug of choice for syphilis?
- What is the drug of choice for GABHS rheumatic fever?
- penicillin G
- penicillin V
Are natural penicillins sensitive to beta-lactamase?
yes
What are some general uses of natural penicillins?
- staph pharyngitis
- soft tissue infections caused by strep A
- some mouth/GI anaerobes (peptococcus/peptostreptococcus)
- meningitis due to N. meningitides, S. pneumo, Listeria
What are the drugs in the antistaphylococcal penicillins?
- dicloxacillin
- methicillin
- oxacillin
- nafcillin
- What is the spectrum of dicloxacillin?
- Does it cover gram +/gram -?
- What is its resistance to beta-lactamase?
- Is there aerobic coverage?
- What do you use dicloxacillin to treat?
- narrow spectrum
- gram +
- beta-lactamase resistant
- no aerobic coverage
- MSSA
- What antistaphylococcal penicillin won’t be used to treatment, only testing purposes?
- What are the side effects of nafcillin?
- methicillin
- nephritis, neutropenia
What drugs are included in the aminopenicillins?
- amoxicillin
- ampicillin
- What is the spectrum of aminopenicillins?
- Do they cover gram+ or gram -?
- What is their resistance to beta-lactamase?
- What are they used to treat?
- broader spectrum
- good gram +, some gram -
- beta-lactamase sensitive
- H. flu, E. coli
What is the drug of choice for Listeria monocytogenes (meningitis)? How is this drug given for this treatment?
ampicillin - IV
What can you use amoxicillin to treat?
- empirical treatment of sinusitis, otitis media (strep)
- premed for endocarditis prophylaxis during dental/invasive procedures
- What can you add to aminopenicillins to allow for treatment of MSSA?
- What are inhibitor combinations for amoxicillin and ampicillin?
- beta-lactamase inhibitors
combinations: - ampicillin/sulbactam
- amoxicillin/clavulanic acid
What are the drugs in the antipseudomonal penicillins?
- piperacillin
- carbenicillin
- ticarcillin
- What is the spectrum of piperacillin?
- What does this drug cover, gram +/-?
- What is its resistance to beta-lactamase?
- What is its route of administration?
- What is this drug used to treat?
- broad spectrum
- good gram +, improved gram -
- beta-lactamase sensitive
- IV only
- Pseudomonas aeruginosa, polymicrobial, and nosocomial infections
What is piperacillin used to treat?
- pseudomonas aeruginosa
- polymicrobial infections
- nosocomial infections
- What are antipseudomonal penicillins effective in treating with the addition of beta-lactamase inhibitors?
- Why would we not use this?
- Which antipseudomonal penicillin is the most potent?
- Antipseudomonal penicillins provide less coverage to what than ampicillin?
- MSSA
- there are other drugs that can treat MSSA; we don’t want to build resistance
- piperacillin
- less staph and strep coverage
What are the different types of side effects/reactions to penicillins?
- type I: immediate response (anaphylactic shock)
- type II: penicillin-associated hemolytic anemia (autoimmune)
- type III: delayed response (skin rash, glomerular nephritis, polyarthritis, pericarditis/pleuritic, lymphadenopathy, angioedema)
- What percentage of patients allergic to penicillins will be allergic to cephalosporins?
- What is it okay to give cephalosporins in pts allergic to PCN?
- 10%
- okay to give to pts with type II or III reactions
What are other side effects of penicillins?
- ampicillin-associated maculopapular rash
- diarrhea (poor absorption)
- nephritis
- neurotoxicity w/ high doses given intrathecally; seizures
- hematologic toxicity (piperacillin)
- cation toxicity (hypokalemia/hyponatremia)
What side effect does piperacillin cause?
hematologic toxicity
What is the MOA of penicillins?
- bactericidal
- contain beta-lactam ring that interacts with PBP
- inhibits transpeptidase (prevents cross-linking of peptidoglycan=weak cell wall)
- binds autolysin inhibitors = increases autolysin activity = breakdown of cell wall
- requires actively proliferating bacteria
What drugs treat MRSA?
- sulfamethoxazole/TMP
- clindamycin
- fluoroquinolones
- vancomycin
- daptomycin
- linezolid
What drugs are in the first generation of cephalosporins? What are their routes of administration?
- cephalexin-po
- cefadroxil-po
- cefazolin-IV
What is the coverage of cephalexin?
- good gram + (MSSA, staph, strep)
- limited gram - (PEcK)
**P. mirabilis, E. coli, K. pneumo - not good anaerobic coverage (no B. fragilis)
What is the resistance to beta-lactamase of cephalexin?
not sensitive to beta-lactamase
What are the general uses of first generation cephalosporins?
- skin/soft tissue infections (not bites)
- URI
- cefazolin (surgical prophylaxis for orthoped surgeries d/t good bone penetration)
- oral routes = not for serious infections
If a patient has type I reactions to PCN and is in need for treatment for MSSA, what antibiotic can you give them?
cephalexin
- How is cephalexin excreted?
- What is the cross-reactivity it has to PCN allergy?
- renally eliminated
- 10% cross-reactivity
What are the drugs in the second generation cephalosporins? What are their routes of administration?
- cefuroxime-po/IV
- cefprozil-po
- cefaclor-po
- cefoxitin-IV
- cefotetan-IV
What is the coverage of second generation cephalosporins?
- same as 1st generation coverage
- more gram - (HENPEcK)
** H. flu
** Enterobacter
** Neisseria
** P. mirabilis
** E. coli
** K. pneumo - anaerobic coverage of B. fragilis w/ cefoxitin, cefotetan
What are some general uses of second generation cephalosporins?
- CAP
- otitis media
- respiratory infections
- sinusitis
- skin/soft tissue infections
- MSSA
- cefuroxime not good with gut anaerobes
- cefoxitin, cefotetan good gut/pelvic coverage
What are some of the drugs included in the third generation cephalosporins? What are their routes of administration?
- cefdinir-po
- ceftriaxone-IV/IM
What is the coverage of third generation cephalosporins?
- vary in gram +
- great gram -
**Serratia marcescens, no enterobacter
**ceftazidime covers. P. aeruginosa
What are the characteristics of ceftriaxone?
- third generation cephalosporin
- longest half-life of all cephalosporins
- excreted in bile (good for pts w/renal failure)
- good bone pentration
- commonly used in gonorrhea treatment
- effective in HACEK endocarditis
Which cephalosporin is commonly used in gonorrhea treatment?
ceftriaxone
What are the general uses of third generation cephalosporins?
- bacterial meningitis
- HAP
- Lyme disease
- ceftriaxone/cefotaxime: meningitis from pneumococci, H. flu, meningococci; no L. monocytogenes; empiric tx in serious infections, sepsis
Third generation cephalosporins have what type of resistance to beta-lactamase?
they are sensitive to beta-lactamases
- What type of infections are you going to use third generation cephalosporins?
- What type of spectrum does cefdinir have?
- What can you use cefdinir to treat?
- What can IV preps of third generation cephalosporins cross?
- serious infections
- broader spectrum
- otitis media, CAP, sinusitis
- BBB
What drug is a fourth generation cephalosporin? What is its route of administration?
- cefepime-IV
What is the coverage of cefepime?
- good gram + (MSSA)
- good gram - (enterobacter, p. aeruginosa)
What can you use cefepime to treat?
- p. aeruginosa infections
- only ceph for enterobacter and serratia
- meningitis
- CAP
What is the sensitivity of cefepime to beta-lactamase?
used to be resistance but is now becoming more sensitive
What drug name is the fifth generation cephalosporin? What is its route of administration?
- ceftarolene-IV
What is the coverage of ceftarolene?
- enhanced gram + (MSSA, S. pneumo, E. faecilis)
- gram -
- no pseudomonas
- poor anaerobic coverage
What can you use ceftarolene to treat?
- MSSA
- skin/soft tissue infections
- CAP
What are the side effects of cephalosporins?
- hypersensitivity
- 10% cross-reactivity with PCN (occurs in 1st gen more often) = don’t use w/ pts who have had anaphylactic rxns to PCN
What is the MOA of cephalosporins?
- binds to PBP and autolysin inhibitors
- interrupts cell wall synthesis and activate autolysins
- bactericidal
- Where are cephalosporins distributed?
- How are they excreted?
- body fluids, CSF, bone
- renally excreted except for ceftriaxone which is excreted in bile
- What are the cephalosporin + inhibitor combinations?
- What do they cover?
- What are they FDA approved to treat?
inhibitor combo
- ceftolozone/tazobactam
- ceftazidime/avibactam
coverage
- excellent gram -
- P. aeruginosa
FDA approval
- complicated intra-abdominal infections along with anaerobic infections
- complicated UTI
- HAP and VAP
- What drug is a monobactam?
- What is its route of administration?
- What is its coverage?
- aztreonam
- IV/IM
- limited gram - (covers P. aeruginosa)
- no gram + or anaerobic infections
What are the side effects of aztreonam?
- no cross rxn with PCN
- same allergies as PCN
What can you use aztreonam to treat?
pseudomonas treatment especially in cases where pt is allergic to PCN (type I rxn)
What are the drugs included in carbapenems? What are their routes of administration?
- imipenem/cilastin-IV/IM
- doripenem
- ertopenem
- meropenem
What is the coverage of carbapenems?
- gram +
- gram - (P. aeruginosa)
- anaerobes
What can you use carbapenems to treat?
- pseudomonas infections when organism is resistant to other drugs
- mixed infections
- very effective in enterobacter infections
What can you use to treat enterobacter infections due to them being very effective in treating these?
carbapenems (imipenem/cilastin)
What are the adverse reactions of carbapenems?
- N/V/D
- rash
- 1% cross reactivity with PCN
- imipenem: seizures, mental status changes
What are the adverse reactions of imipenem/cilastin?
- seizures
- mental status changes
- How are carbapenems excreted?
- Why do you need to give cilastin with imipenem?
- When would you use carbapenems?
- renally excreted
- imipenem is inactivated in renal tubules; cilastin inhibits dehydropeptidase which stops imipenem from being broken down
- would use them if pts culture came back pseudomonas resistant to other drugs (last resort due to severe side effects)
What drug is a glycopeptide antibiotic?
vancomycin
What is the MOA of vancomycin?
- inhibits glycosylation of NAM-NAG units
- doesn’t rely on transpeptidase
- bactericidal
What is the coverage of vancomycin?
best for gram + (MRSA, MRSE, enterococci, clostridium)
What are the clinical uses of vancomycin?
- MRSA sepsis, endocarditis
- vanco + gentamicin = enterococcal endocarditis where pt is allergic to PCN
- in combo with cephs = meningitis
- C. diff via oral route
What type of vancomycin would you use to treat C. diff?
oral vancomycin
What are the adverse effects of vancomycin?
- red man syndrome (given too rapidly)
- phlebitis
- ototoxicity/nephrotoxicity if given with other toxic drugs like aminoglycosides
What is the distribution of vancomycin?
- CSF and adipose tissue
- dose adjust in renal impairment:
**normal half-life: 6-10 hours
**renal disease half-life: 200 hours
- What should you think of treating when using vancomycin?
- What is vancomycin often given with?
- What is the toxicity of this drug?
- MRSA
- gentamicin
- very toxic
What drugs are protein synthesis inhibitors?
- aminoglycosides
- tetracyclines
- macrolides
- clindamycin
- chloramphenicol
- linezolid
What drug in included in aminoglycosides we need to know?
gentamicin
What is the coverage of aminoglycosides?
- used w/ beta-lactams in serious gram - (vanco), gram + (endocarditis), and TB
- no anaerobic coverage
What is the MOA of aminoglycosides?
- passes through porin channels
- uses oxygen dependent active transport
- enhanced by other cell wall inhibitors
- binds 30S subunit of ribosome irreversibly
- bactericidal
What are the indications of aminoglycosides?
- aerobic gram + (steph/strep with beta-lactams)
- aerobic gram - (klebsiella, E. coli, proteus with beta-lactams; pseudomonas with antipseudomonals; brucella, taluremia, plague with tetracyclines)
- severe gram - infections in combo
- group B strep in neonates
- intrathecal for gram - meningitis
What is treated when you combine aminoglycosides with tetracyclines?
- brucella
- taluremia
- plague
What is the distribution of gentamicin?
- poor oral absorption
- not metabolized
- distributes poorly to CSF/lungs (low Vd)
- pregnancy category C/D = don’t use in lactation
What are the adverse affects of gentamicin?
- nephrotoxicity
- ototoxicity; can cause permanent deafness
- What is the route of administration of aminoglycosides?
- Will you use them by themselves in systemic infections?
- What is an example of this?
- IV, IM, intrathecally, intraventricular, topical
- no
- using vanco for gram +, gentamicin for gram -, so they can be used together in serious infections