Antibiotics Flashcards
What are some Atypical bacteria?
-Chlamydia
-Legionella
-Mycoplasma
-Mycobacterium
What are the stains for the different bacteria?
Gram + (dark purple) <–Think cell wall
Gram - (pink) <– Thin cell wall
Atypical (no stain) <–No cell wall
HNPEK meaning
H - H. influenzae
N - Neisseria sp.
P - Proteus mirabilis
E - E. coli
K - Klebsiella sp.
CAPES meaning
C - Citrobacter
A - Acinetobacter
P - Providencia & Pseudomonas
E - Enterobacter
S - Serratia
What is the meaning of VRE?
Vancomycin resistant enterococcus
What is the meaning of ESBL?
Extended-spectrum beta lactamases
What is the meaning of CRE?
Carbapenem resistant enterobacterales
Which antibiotic has a Boxed Warning for C. difficile?
Clindamycin
*Note that all antibiotics have the potential to cause c.diff. Clindamycin was the first to be associated with c.diff, hence the boxed warning.
What are the hydrophilic antibiotics?
1) Beta lactams
2) Aminoglycosides
3) Glycopeptides
4) Daptomycin
5) Polymyxins
*These are renally excreted!
What are the lipophilic antibiotics?
1) Quinolones
2) Macrolides
3) Rifampin
4) Linezolid
5) Tetracycline
6) Chloramphenicol
*These are hepatically cleared!
*These have excellent bioavailability, therefore their IV:PO is usually 1:1.
What are the concentration-dependent antibiotics?
1) Aminoglycosides
2) Quinolones
3) Daptomycin
*Goal is for high peak and low trough.
*We give large dose over a long interval
What are the time-dependent killing antibiotics?
1) Beta lactams (Penicillins, cephalosporins, carbapenems)
*Goal is to maintain drug level above MIC for most of the dosing interval
*We give a shorter dosing interval, continuous infusion.
MSSA Drugs
1) Penicillins
2) Cephalosporins
MRSA Drugs
1) Vancomycin
2) Linezolid
3) Daptomycin (not in pneumonia)
4) Ceftaroline
5) SMX/TMP
6) Doxycycline, Minocycline
7) Clindamycin
VRE Drugs
LAPD
1) Linezolid
2) Ampicillin
3) Penicillin G
4) Daptomycin
5) Cystitis Only: Nitrofurantoin, Fosfomycin, Doxycycline
Atypical Drugs
1) Azithromycin, Clarithromycin
2) Doxycycline, Minocycline
3) Quinolones
Pseudomonas aruginosa drugs
1) Combo
-Piperacillin/Tazobactam
-Ceftazidime/Avibactam
-Ceftolozane/Tazobactam
2) Cefepime, Ceftazidime
3) Carbapenems (except Ertapenem)
4) Ciprofloxacin, Levofloxacin
5) Aztreonam
6) Tobramycin
7) Polymyxin B
ESBL Drugs
1) Carbapenems
2) Ceftazidime/Avibactam
3) Ceftolozane/tazobactam
CRE Drugs
1) Ceftazidime/Avibactam
2) Meropenem/Vaborbactam
3) Imipenem/Cilastatin/Relebactam
Anaerobe Drugs
1) Metronidazole
2) Beta-lactam/Beta-lactamase inhibitor
3) Carbapenems
4) Cefotetan, Cefoxitin
How do Beta Lactam antibiotics work?
They inhibit bacterial cell wall synthesis by binding to Penicillin Binding Proteins (PBP)
What are the beta lactam antibiotics?
1) Penicillins
2) Cephalosporins
3) Carbapenems
4) Aztreonam
What are the Penicillin antibiotics?
1) Penicillin G, Penicillin VK
2) Amoxicillin, Ampicillin
3) Nafcillin, Oxacillin, Dicloxacillin (Anti-staph)
4) Amox/clauv, Amp/Sulbactam
5) Pip/Tazo
Penicillin G & VK coverage
Gram Positives (Strep, not Staph)
Amoxicillin and Ampicillin coverage
Gram Positives (Strep, not Staph) + Gram Negatives (HNPEK)
Amox/Clav and Amp/Sulbactam coverage
Gram Positive + Gram Negative (HNPEK) + MSSA + B. fragilis
Pip/Tazo coverage
Gram Positive + Gram Negative (HNPEK) + MSSA + B. fragilis + CAPES + Pseudomonas
*This is the only penicillin that is active against Pseudomonas.
Nafcillin, Dicloxacillin and Oxacillin
MSSA and Streptococci
What DONT Penicillins cover?
1) NO Atypicals
2) NO MRSA
Penicillins with their formulation
Penicillin VK: PO
Penicillin G: IV and IM
Amoxicillin: PO
Ampicillin: IV
Amox/Clav: PO
Amp/Sul: IV
Pip/Tazo: IV
Dicloxacillin: PO
Nafcillin and Oxacillin: IV
When NOT to choose a penicillin/cephalosporin/carbapenem for a patient?
1) Beta-lactam allergy
2) Risk of seizure
*All Penicillins, Carbapenems and Cephalosporins increase the risk of seizures if accumulation occurs.
*If a patient presents with a penicillin allergy, there is a risk of cross reactivity if given a cephalosporin or carbapenem…so avoid this!
First generation Cephalosporins & coverage
-Cefazolin (IV)
-Cephalexin (PO)
Covers Staph, Strep, PEK, mouth anaerobes
Second generation Cephalosporins & coverage
-Cefuroxime (IV/IM/PO)
-Cefotetan (IV/IM)
-Cefoxitin (IV/IM)
These have the same coverage as the first generation (strep, staph, PEK, mouth anaerobes) but added Gram negative (HNPEK) activity.
Third generation Cephalosporins & coverage
-Cefdinir (PO)
-Ceftriaxone (IV)
-Ceftazidime (IV) <– Pseudomonas coverage
Fourth generation Cephalosporins & coverage
-Cefepime
*Broad Spectrum: Gram +, HNPEK, CAPES, Pseudomonas
Fifth generation Cephalosporins & coverage
-Ceftaroline <–MRSA coverage
What does the cephalosporins NOT cover?
1) NO Enterococcus
2) NO Atypicals
What are our main oral cephalosporins?
1) Cephalexin
2) Cefuroxime
3) Cefdinir
What are the Carbapenem antibiotics?
1) Meropenem
2) Ertapenem
3) Doripenem
4) Imipenem/Cilastatin
*All IV
When are Carbapenems preferred?
-They are the drug of choice for ESBL-producing organisms
-Pseudomonas (except ertapenem)
-Polymicrobial infections (Diabetic foot infections)
-Empiric therapy when resistant organisms are suspected
What does Carbapenems NOT cover?
1) Atypicals
2) VRE
3) MRSA
4) C. diff
Ertapenem does not cover PEA (Pseudomonas, Enterococcus, Acinetobacter)
What is the coverage of Aztreonam?
Gram negative organisms:
-Pseudomonas
-CAPES
*This can be used in patients with beta-lactam/penicillin allergy
Which Beta-Lactam covers pseudomonas?
1) Ceftazidime, Ceftazidime/Avibactam
2) Aztreonam
3) Ceftolozane/Tazobactam
4) Cefepime
5) All Carbapenems except Ertapenem
Which Beta-Lactam covers enterococcus?
1) Penicillin
2) Amoxicillin, Amoxicillin/Clav
3) Ampicillin/Sulbactam
4) Pip/Tazo
5) All Carbapenems except Ertapenem
How do Aminoglycosides work?
They bind to the ribosome, which interferes with bacterial protein synthesis and results in a defective bacterial cell membrane.
Coverage of Aminoglycosides
-Gram negatives (including Pseudomonas)
-Synergy with beta-lactams for gram positives (Staph & Enterococci)
Dosing for Aminoglycosides
1) Traditional (1 - 2.5 mg/kg IV q8h)
Draw trough 30 min before 4th dose
Draw peak 30 mins after 4th dose infusion
Ideal Trough : <2
2) Extended Interval (4 - 7 mg/kg IV q24h)
Toxicities of Aminoglycosides
1) Renal Damage
2) Ototoxicity (Ear)
*Avoid when taking with other Nephrotoxic drugs (AmpB, Cisplatin, Polymixins, Cyclosporine, Loop Diuretics, NSAIDs, Radiocontrast dye, Tacrolimus, Vancomycin)
What are the Aminoglycoside drugs?
-Gentamicin
-Tobramycin
-Amikacin
How do Quinolones work?
They inhibit bacterial DNA topoisomerase and DNA gyrase. This promotes breakage of double-stranded DNA.
What are the Boxed Warnings for Quinolones?
1) Tendon rupture (usually Achilles)
2) Peripheral Neuropathy
3) CNS effects (seizures)
*Use last-line
What are the main Quinolone drugs?
1- Ciprofloxacin
2- Levofloxacin
3- Moxifloxacin
4- Delafloxacin
Notes about Quinolones
-They interact with cations (antacids)
- They can cause QT prolongation and cause psych disturbances
Coverage of Quinolones
Broad-Spectrum:
-Gram + & -
-Atypicals
Levo and Moxi are considered Respiratory Quinolones, since they are active against Strep pneumoniae.
Cipro and Levo have enhanced activity against pseudomonas, UTI, traveler’s diarrhea.
Moxi have anaerobic activity, and can be used alone for polymicrobial infections. It is the only quinolone that cannot be used for a UTI.
Delafloxacin has MRSA coverage
How do Macrolides work?
They bind to the 50s ribosomal subunit, resulting in the inhibition of the RNA-dependent protein synthesis.
Coverage of Macrolides
-Atypicals
-Respiratory infections (H. influenzae, S. pneumoniae)
What are the Macrolide drugs?
-Azithromycin
-Clarithromycin
-Erythromycin
Macrolide Drug interactions?
Erythromycin and Clarithromycin are CYP3A4 inhibitors, and are contraindicated with simvastatin and lovastatin.
They cause QT prolongation
How do Tetracyclines work?
They inhibit bacterial cell wall synthesis by reversibly binding to the 30s ribosomal subunit.
What are the Tetracycline drugs?
1) Tetracycline
2) Doxycycline
3) Minocycline
What is the coverage of Tetracyclines?
-Gram Positive (Staph, Strep, MRSA)
-Gram Negative (Respiratory flora: Haemophilus, Moraxella)
-Atypicals
-VRE (Vanco Resistant Enterococcus)
Notes about Tetracyclines
-Avoid use in children < 8 years, breastfeeding and pregnancy
-Photosensitivity
-Interacts with divalent cations (Antacids)
-Minocycline: causes DILE (Drug induced lupus erythematosus)
How do Sulfonamides (Sulfamethoxazole) work?
Sulfamethoxazole inhibits dihydrofolic acid formation, which interferes with bacterial folic acid synthesis.
Trimethoprim inhibits the folic acid pathway.
Notes about Bactrim (Sulfamethoxazole/Trimethoprim)
1) Dose is based on Trimethoprim
2) NO breastfeeding, pregnancy,
3) Sulfa Allergy
4) Photosensitivity
5) SJS
6) Do not use if patient has G6PD deficient
Common uses of Bactrim
-Uncomplicated UTI
-MRSA
-Pneumocystis pneumonia
What is the ratio of Sulfamethoxazole to Trimethoprim?
5:1 SMX/TMP
Coverage of Bactrim
-Staph (MRSA)
-Gram negative
NO Coverage for pseudomonas, enterococci, atypicals or anaerobes
What antibiotics are primarily used for Gram Positive infections?
1) Vancomycin
2) Lipoglycopeptides
3) Daptomycin
4) Linezolid
Coverage of Vancomycin
-MRSA
-Streptococci
-Enterococci
-C- difficile (Oral only)
Dosing of Vancomycin
15-20 mg/kg q8-12h (TBW)
If CrCl 20-49: q24h
-Red Man Syndrome with rapid infusion.
-This is a nephrotoxic drug! Monitor CrCl.
-Avoid other nephrotoxic and ototoxic drugs (furosemide, aminoglycosides, cisplatin).
What are the Lipoglycopeptide drugs?
“vancin”
-Telavancin
-Oritavancin
-Dalbavancin
*They have similar coverage as Vancomycin (they are structurally similar)
How do Lipoglycopeptides work?
They inhibit bacterial cell wall synthesis by blocking polymerization and cross-linking of peptidoglycan, and changing cell wall permeability.
How does Daptomycin work?
This inhibits intracellular replication processes including protein synthesis and causes cell death.
Daptomycin coverage
MRSA + VRE
*No activity against Gram Negative organisms and pneumonia bugs.
Warning of Daptomycin
-Rhabdomyolysis
-Myopathy
What are the Oxazolidinone drugs?
-Linezolid
-Tedizolid
How do Linezolid work?
They bind to the 50s subunit of the bacterial ribosome, inhibiting translation and protein synthesis.
Coverage of Linezolid
-MRSA
-VRE
Safety of Linezolid
These have Serotonergic properties.
-Do not use within 14 days of an MAO inhibitor. (Contraindicated)
Side Effects: Serotonin syndrome, myelosuppression, optic neuropathy
How does Clindamycin work?
This reversibly bind to the 50s subunit, inhibiting protein synthesis.
Coverage of Clindamycin
-Strep & Staph
-MRSA
-Anaerobes
How dose metronidazole work?
This cause a loss of helical DNA structure and strand breakage resulting in inhibition of protein synthesis.
How does Fidaxomicin work?
This inhibits RNA polymerase, resulting in inhibition of protein synthesis and cell death.
First line for c. diff infections.
How does Rifaximin work?
These inhibits bacterial RNA synthesis by binding to bacterial DNA-dependent RNA polymerase.
Used for Travelers diarrhea, prevention of hepatic encephalopathy.
What are our Urinary Agents?
1) Nitrofurantoin
2) Fosfomycin
3) Bactrim
How does Fosfomycin work?
Inhibits bacterial cell wall synthesis by inactivating the enzyme pyruval tansferase.
Coverage of Fosfomycin
-E. coli (including ESBL)
-E. faecalis (including VRE)
Coverage of Nitrofurantoin
-E. coli
-Klebsiella
-Enterobacter
-Staph aureus
-VRE
This is the drug of choice for Uncomplicated UTI.
Dosing: 100 mg BID x 5 days
C. difficile drugs for treatment
1) Metronidazole
2) Vancomycin
3) Fidaxomicin
Which drugs do NOT require Renal Adjustments?
1) Anti-staph Penicillins
2) Ceftriaxone
3) Clindamycin
4) Doxycycline
5) Azithromycin, Erythromycin
6) Metronidazole
7) Moxifloxacin
8) Linezolid
