AntibacterialAntibioticsC Flashcards
A drug may be static or cidal depending on what factors?
Concentration of drug, site of infection, and infecting organism
What is the aminoglycoside spectrum of activity?
Active against aerobic gram ñ bacilli, usually used in combo with other agents, exhibits concentration-dependent killing and have a pronounced post- antibiotic effect
What are the most widely used aminoglycosides?
Gentamicin, tobramycin, amikacin
Which drugs related to aminoglycosides are used to tx gonorrhea in pts with PCN allergies?
Streptomycin
What are the ADRs of aminoglycosides
Ototoxicity- may be reversible, Nephrotoxicity- - usually reversible, Avoid in sulfite allergies
Can aminoglycosides be orally absorbed?
No
What are the gentomicin dosing strategies?
Once daily- recommended 5-7mg/kg daily, Multiple daily: synergy dose- load 3mg/kg then 1mg/kg Q 8hrs maintenance
What are aminoglycoside drug interactions?
Increased nephrotoxicity w/ loop diuretics, Resp depression when given w/ non depolarizing muscle relaxants, Neomycin affects digoxin levels- alters GI flora for metabolism
What are category D aminoglycosides for special populations?
Amikacin, streptomycin, tobramycin, kanamycin, 8th cranial nerve toxicity in fetus
What are category C aminoglycosides for special populations?
Gentamicin, neomycin- minimal absorption PO
What is another special population for aminoglycosides?
Breastfeeding- AAP compatible
What are the 3 groups of tetracyclines based on PK traits?
Short-acting- oxytetracycline, tetracycline, Intermediate- acting- demeclocycline (no longer an antibiotic), Long-acting- preferred, doxycycline and minocycline
What is the MOA for tetracyclines?
Inhibits protein synthesis, reversibly binds to 30S subunit of RNA, Bacteriostatic
What is the most important mechanism of resistance?
Bacterial efflux pump
What are the most common ADRs of tetrcayclines?
N,V,D
What rxn is limited to minocycline use?
Vestibular, lupus like rxn
How are tetracyclines eliminated?
Mostly kidneys
What is the 3rd generation TCN and what is it indicated for?
Tigecycline, Tx : complicated intraabdominal infections, complicated skin infections
What drug is reserved for life threatening infections like typhoid and why?
Chloramphenicol, Bc it can cause blood dyscrasias
What 2 populations should chloramphenicol NEVER be used in?
Pregnant women and neonates
What are the macrolides and their MOA?
Erythromycin, clanthromycin, azithromycin, Inhibit protein synthesis, bacteriostatic at low doses but bactericidal at high concentrations
What is the spectrum of activity for macrolides?
Erythromycin: gram + bacteria and spirochets ( legionella, N.gonorrheae, n. meningitidis, h influenzae), Clarithromycin and Azithromycin: gram + and anaerobic (h influenzae, h pylori, mycobacterium avium, )
Which macrolide is H. influenzae resistant?
Erythromycin
What are the ADRs of erythromycin?
GI- N/V/D most common. Some CV, cholestatic jaundice
Why is erythromycin administered as enteric coated tablet or capsule?
Base is destroyed in the stomach acid
What are drug interactions for macrolides?
CYP3A4(erythro/ clarithro) Lots of interactions
Is azithromycin metabolized by the CYP3A4?
NO
What are ketolides and what organisms do they have activity against?
New macrolide, semi-synthetic derivative of erythro, Increased activity against gram + and macrolide resistant strains
What is telithromycin indicated for?
CAP, sinusitis, bronchitis
What is the black box for telithromycin?
Liver failure, death, risk of ventricular arrhythmias, contraindication for MG
What is the spectrum of activity for clindamycin and what is its most important indication?
Gram +, and anerobes , Most important indication for tx of anaerobic or mixed infections
What is the topical indication for clindamycin?
acne
Clindamycin is the most common antibiotic to cause what?
C diff
What are the indications of Quinupristin- dalfopristin?
Life threatening infections associated with vanco-resistant bacteremia ( VRE)
What are the oxazolidinones and their indications?
Linezolid and tedizoid, VRE/MRSA
When is linezoid a bacteriostatic? Cidal?
Static: enterococci/staph, Cidal: strep
What do you need to be concerned for when prescribing tedizoid
C diff
What is the tRNA inhibitor and its indications?
Mupirocin, Topical skin tx- like impetigo. ( bactroban)
