IPS Flashcards
Name the 3 macrolides
Erythromycin ORAL/IV
Clarithromycin ORAL
Azithromycin (Z pack) ORAL/IV
Are macrolides bacteriostatic or bacteriocidal?
Bacteriostatic (conc. and organism dependent)
Which subunit do macrolides bind to?
50s
What is the MOA of the macrolides?
Inhibition of protein synthesis
Which of the macrolides is an alternative to penicillin if pt has penicillin allergy?
Erythromycin
What is the spectrum coverage of the macrolides?
G+
Erythromycin is the DOC for:
Legionella species
Mycoplasma pneumoniae
Chlamydia pneumoniae and C. pneumoniae
What is the MOR of the macrolides
- Efflux pumps
- Methylation of drug binding site
Macrolide toxicity
-Diarrhea
-GI effects (Clarithro least, Erythro most)
-QT prolongation
-Drug interacts (CYP3A4) (Azithro most favorable)
***Toxicity is synergistic
SEE CHART SLIDE 14
Which abx belongs to the Ketolide family?
Telithromycin ORAL
Are Ketolides bacteriostatic or bacteriocidal?
Bacteriostatic
MOA for Ketolides
Binds to 50s subunit
What is the spectrum of activity of Telithromycin (ketolides)
- Broad spectrum
- Good against respiratory pathogens including erythromycin and penicillin-resistant pneumococci
What is telithromycin used for?
Community acquired pneumoniae (2nd choice after macrolides)
Telithromycin (Ketolide) toxicity
- Very hepatotoxic- should NOT be used in children
- Diarrhea
Which enzyme is Telithryomycin an inhibitor of? Is this reversible or irreversible?
REVERSIBLE inhibitor of CYP3A4 enzymes
Is Clindamycin bacteriostatic or bacteriocidal?
- Bacteriostatic
- Can be bacteriocidal depending on concentration at the site of action and on the specific susceptibility of the organism
What is the MOA of Clindamycin?
Reversibly binds to 50s subunit - protein synthesis inhibition
What is the spectrum of Clindamycin?
Aerobic G+
Some anaerobic G- and G+
What is Clindamycin useful in treating?
- Concentrates highly in bones; useful for osteomyelitis
- Acne (topical)
- Toxoplasma enchephalitis (despite poor CNS conc.)
- Toxic Shock Syndrome (use with vanco, nafcillin, or first gen cephalorsporin
What are the adverse side effects of Clindamycin
Well known cause of pseudomonas colitis (C. diff infection)
-Take them off Clinda and put them on Vanco
Clindamycin is the DOC for
- Strep pyogenes
- Clostridia
What drug is in the Oxazolidinones family?
Linezolid IV/ORAL
What is the MOA for Linezolid?
Reversibly inhibits protein synthesis by binding to 50s subunit
What is Linezolid an inhibitor of?
Reversible, non-selective inhiibtor of monamine oxidase (MAO)
What is the spectrum coverage of Linezolid?
Aerobic G+ organisms
Is Linezolid bacteriostatic or bacteriocidal?
Bacteriostatic EXCEPT it is cidal for streptococci
What are the uses of Linezolid?
- Bacterial pneumoniae
- Skin infections
- VRE infections
- MRSA infections
Toxicity of Linezolid
- Usual side effects and interactions as the MAO inhibitors
- Hypersensitivty
- Pheochromocytomia (kidney tumor)
What are the drug interactions of Linezolid?
Heterocyclic antidepressants, tricyclic antidepressantsm SSRIs
Name the streptogrammins
Dalfopristin
Quinupristin
Streptogrammin MOA
Inhibit protein synthesis, binds to 50s subunit
What is an important pharmacokinetic factor for the streptogrammins
When administered together via IV, they have a synergistic
Are streptogrammins bacteriostatic or bacteriocidal?
When used TOGETHER, they are bacterocidal
Streptogrammin spectrum
G+
Adverse reactions of streptogrammins
- Hepatotoxicity, N/V, pain, pruritus, rash
- INHIBIT THE P450 drug metabolizing system (think warfarin)
What are the 5 Aminoglycosides
Streptomycin IV/IM Gentamycin IV/IM/TOPICAL Tobramycin IV/IM/TOPICAL Amikacin IV/IM Neomycin ORAL/TOPICAL
Are the Aminoglycosides static or cidal?
CIDAL under AEROBIC conditions only
Aminoglycoside MOA
Irreversibly inhibit protein synthesis; 30s subunit
What should Aminoglycosides always be combined with?
B-Lactam abx
- B-lactams break down the cell wall
- Aminoglycosides do the killing from the inside
What is unique about the Aminoglycoside structure? What do Aminoglycosides require to work?
Large and polar, therefore must be actively transported in. This is an oxygen requiring process!
We give a pt an aminoglycoside when there is a suspicion of (2 things):
Sepsis or endocarditis
Aminoglycosides are the DOC for:
P. aeruginosa
Why do we use a megadose of aminoglycosides once a day?
Concentration dependent killing
Have significant PAE
Aminoglycoside toxicity
Ototoxicity
Nephrotoxicity
***Dependent on duration of TIME the CONCENTRATION of drug is used above threshold
MOR against Aminoglycosides
-Deficiency of ribosomal receptors
-Lack of permeability into bacteria
-Enzymatic modification by bacteria
(cross-resistance: bacteria resistant to one aminoglycoside is likely resistant to another aminoglycoside)
What are the 3 abx that bind to the 30s subunit?
-Aminoglycosides
-Tetracyclines (broad spectrum abx)
-Glycylcyclines (broad spectrum abx)
All other IPS bind to 50s
What are the Gram + IPS?
- Macrolides
- Streptogrammins
- Oxazolidinones
POSITIVE Memories Start in October
What are the broad spectrum IPS?
- Broad spectrum abx
- Ketolides
- Clindamycin
3 broads Kissed Cliff
What abx is associated w/ fatal aplastic anemia, gray baby syndrome, and bone marrow suppression?
Chloramphenicol
Name the 3 classes of broad spectrum abx
Chloramphenicol
Tetracyclines
Glycylcyclines
Are the broad spectrum abx static or cidal?
Static
What subunits do each broad spectrum abx bind to?
Chloramphenical 50s
Tetracyclines and Glycylcyclines 30s
MOA for broad spectrum abx
Inhibit protein synthesis (w/ respective subunits)
What can chloramphenicol inhibit in mammalian cells that makes it so toxic?
Inhibit mitochondrial protein synthesis in mammalian cells; results in many adverse affects
What are some therapeutic uses of chloramphenicol
DUE TO TOXIC EFFECTS, ONLY USE THIS DRUG AS A LAST RESORT!
- Typhoid fever
- Meningitis
- Eye infections
- G- infections
- Lyme/tick related illnesses
Toxicities of Chloramphenicol
- Fatal aplastic anemia
- Bone marrow suppression
- Gray baby syndrome
Which chloramphenicol toxicities are dose-dependent and dose-independent
- Bone marrow suppression: Dose DEPENDENT
- Fatal aplastic anemia: Dose INDEPENDENT
Which drug as the best CNS penetration?
Chloramphenicol (but incredibly toxic)
Chloramphenicol MOR
- Efflux pumps
- Acetyl transferase produced my resistant organisms inactivates chloramphenicol
Name the 3 Tetracyclines
- Tetracycline ORAL/TOPICAL
- Doxycycline ORAL
- Minocycline ORAL
Tetracyclines are the DOC for:
- H. pylori
- Mycoplasma pneumoniae
- Chlamydia infections
- Virbrio cholera
- Early lyme disease
Tetracycline MOR
Efflux pumps
What are 2 important pharmacokinetic factors regarding tetracycline
- Avoid taking vitamins (Tetracycline chelates with Ca, Fe, and Al)
- Deposits in bone and teeth
Adverse affects of tetracyclines? Who should NOT be prescribed tetracyclines?
- Normal flor changes
- Bone growth inhibition
- Teeth discolorationg
- Photosensitivity
*Do not prescribe to pregnant women or childreen 8 years old or younger
What drug belongs in the Glycylcycline family
Tigecycline
Tigecycline has a similar spectrum to tetra, doxy, and minocycline, PLUS
Activity against tetra-cycline resistant organisms
Adverse affects of tigecycline
Similar to Tetracyclines + nausea and vomiting
What can tigacycline be used to treat
MRSA
MRSE
PRSP
VRE