antibiotic inhibiting protein synthesis Flashcards
Is linezolid “-static” or “-cidial” for enterococci?
“-static”
Is linezolid “-static” or “-cidial” for strept?
“-cidal”
What is the basic structure that makes aminoglycosides part of one class?
Aminocyclitol ring
What inhibits aminoglycosides?
Acidic pH and anaerobic conditions
Besides protein synthesis inhibition, what other effects do aminoglycosides have?
Inhibit cell wall membrane
What other classes do aminoglycosides work well with?
Penicillin and cephalosporins
What are the 3 known mechanisms of resistance for aminoglycosides?
Modification of aminoglycoside molecule
binding of aminoglycosides on rRNA altered
reduced uptake of aminoglycosides
What is a way to combat resistance with aminoglycosides?
use with agents that target cell wall in conjunction
What is aminoglycoside active against?
Aerobic gam-negative bacilli
When you add cell wall inhibitors what will aminoglycosides start to work better against?
gram positive bacteria
What are aminoglycosides used for?
UTIs, respiratory tract, skin and soft-tissue infections
When do you use aminoglycosides in combination with other agents?
To broaden coverage in serious illness
bacteremia or sepsis
pseudomonal infections
synergism w/ vancomycin or penicillins in the treatment of endocarditis
When do you get more killing of bacteria for aminoglycosides?
Post-antibiotic effect (after high level is reached)
When do you use streptomycin?
Enterococcal infections
What are 3 common aminoglycosides?
gentamicin
tobramycin
amikacin
What are neomycin and kanamycin limited to?
Oral or topical use due to toxicity
What is spectiomycin used for?
Tx for gonorrhea in PCN allergic patients
What are the two toxicities to be concerned about with aminoglycosides?
Otoxicity
Nephrotoxicity
of the aminoglycoside class, what is the most ototoxic drug?
Streptomycin
In a patient with Parkinson’s or myasthenia gravis, what can happen when they are put on aminoglycosides?
Aggravate muscle weakness; respiratory paralysis
Are hypersensitivity rxns common with aminoglycosides?
No (not used frequently, usually used in hospital)
If a patient has allergies to sulfite, what aminoglycoside should they not be given?
Streptomycin
What aminoglycoside is given to decontaminate bowel (given PO)?
Neomycin
How are aminoglycosides administered?
IV
widely distribute in extracellular fluid
Clearance of aminoglycosides is proportional to what?
creatinine clearance
With vancomycin what levels do you check?
Trough levels
What levels do you check with aminoglycosides?
Peak levels (30 minutes after infusion- allow you to see highest level) trough levels
what type dosing is mostly mentioned for aminoglycosides?
“once daily” dosing
Who should not be given once daily dosing with amionglycosides?
renal insufficiency
Cystic fibrosis
spinal cord infections
burn patients
What weight is used for aminoglycosides?
Actual body weight, adjusted for obese
What drugs can aminoglycosides interact with?
Loop diuretics - nephrotoxicity
Non-depoloarizing muscle relaxant- resp depression
What levels can neomycin (IV) affect?
Digoxin levels (alter GI flora responsible for mechanism)
Most aminoglycosides have what category for pregnancy?
Category D- 8th CN toxicity
What aminoglycosides have a Category C for pregnancy?
Gentamicin
Neomycin
Are aminoglycosides compatible for breastfeeding moms?
Yes
what are the 3 primary tetracyclines?
tetracycline
doxycycline
minocycline
what bacteria do tetracyclines cover?
gram positive
gram negative
aerobic
anaerobes
What is a difficult condition that tetracyclines can kill?
Mycoplasma pneumonia
What drug is used for inhalation anthrax?
Doxycycline
What is a concern with the tetracyline class?
WIll kill off normal flora easily and concern of overgrowth of opportunistic infections.
WHat other conditions do tetracyclines treat?
Chlamydia rickettsia (RMSF) lyme's disease (borrelia burgdorferi) inflammatory acne sinusitis
Is tetracycline long or short acting?
Short acting
Are minocycline and doxycycline long or short acting?
long acting (better option)
What do tetracyclines bind?
Reversibly bind RNA
Are tetracyclines “-static” or “-cidal”
bacteriostatic
what is the most important mechanism of resistance to tetracycline?
Bacterial efflux pump
what are the ROA for tetracycline?
Oral
parenteral
ophthalmic
What is the most common side effect with tetracyclines?
GI effects (N/V/D) with oral and parenteral routes potential for C. diff/ candidiasis
Who should tetracyclines not be administered to?
Young children and pregnant moms
tetracyclines binds to bony structures and teeth
will get grey discoloration on teeth
what pregnancy category are tetracyclines?
Category D
what is usually the initial therapy for lyme disease?
doxycycline
What are some other ADRs of tetracyclines?
photosensitization
pseudotumor cerebri
What are some ADRs with minocycline?
Dizziness, vertigo
lupus-like rxn (reversible)
Combination of tetracycline and what can inhibit absorption?
Dairy
Antacids
Mg, Iron, zinc, aluminum hydroxide
Where do tetracyclines distribute?
Body, including meninges
How are tetracyclines eliminated?
mostly kidneys (except doxy- hepatic) dosage adjustments may be necessary
What is a third generation TCN what has broad spectrum antimicrobial activity, including MRSA?
Tigecycline (Tyacil)
Why was tigecycline developed?
Overcome bacterial resistance mechanisms to TCNs (efflux and ribosomal mutations)
What is chloramphenicol reserved for?
Life threatening infections: typhoid fever, RMSF, and meningitis in patients allergic to PCN.
What is the bad side effect of chloramphenicol?
blood dyscrasias
Is chloramphenicol bascteriostatic or bactericidial?
Both; depending on bacteria speciesis
Who can’t chloramphenicol be used in?
Pregnant women
Neonates
What types of resistance are there with chloramphenicol?
plasmid born
decreased cellular permeability
modification of enzymes- acetyltransferases
What is an example of a macrolide?
Erythromycin
What are some semisynthetic derviates of erythromycin? (also macrolide class)
Clarithromycin
Azithromycin
(both are more acid stable)
Are macrolides bacteriostatic or bacteriocidial?
bacteriostatic;
at high concentrations or with rapid bacterial groups become bactericidal
What macrolide has more anaerobic coverage?
Azithromycin
What macrolide has the most reistatnce?
erythromycin
What does erythromycin work against?
Gram (+) bacteria and spirochetes. Specific bacteria include: legionella pneumophila, N gonorrhoeae, N. menigitidis, Poor anaerobic coverage.
What does clarithromycin act against?
against gram (+) and anaerobic bacteria, H. influenzae, H. pylori, mycobacterium avium
Does erythromycin work against h. influenze?
No, but the semisynthetic deviates do?
Resistance to macrolides is usualuly waht?
Plasmid mediated
What is erythromycin base destroyed by?
Stomach acid, must be administered with enteric coated tablet
Where are macrolides widely distributed?
Prostate (but not to CNS)
how can macrolides be administered?
PO, IV, ophthalmic
How are erythro and azithro excreted?
Unchanged in bile
How is clarithromycin excreted?
Unchanged in bile and urine (May have to make renal adjustments)
What side effects are most common with macrlides?
Gastrointestinal
When can you see sholestatic jaundice?
Estolate salt form of erythromycin
when do you see CV issues with macrolids?
IV administration (QT prolongations)
What does clarithromycin have enhanced coverage of?
Atypical mycobacteria
compared to erythromycin, clarithyromycin has less what?
GI upset and BID dosing
What do you get greater of what azithromycin?
Greater tissue penetration
prolonged intracellular half-life
Erythro and clarithromycin inhibit what?
CYP3A4
Ketolides have a greater potency against what? (then macrolides)
greater potency against gram positive organisms
What does telithromycin have a black box warning for?
Liver failure and deaths
increased risk of ventricular arrhythmias
Patients with what should not take telithromycin?
myasthenia gravis
How is telithromycin eliminated?
hepatic metabolism with eliminiation in bile and urine
Talithromycin inhibits what?
P450 class
What is the main antibiotic associated with lincosamides?
Clindamycin
What does clindamycin work well for?
Strep, staph, pneumococci
anaerobes*** (except C diff)
How is clindamycin available?
oral, IV, topical
What is the most important indication for clindamycin?
Anaerobic or mixed infections
Aspiration pneumonia
What can clindamycin be topically used for?
inflammatory acne
what is the most common antibiotic to cause C. diff?
clindamycin (IV)
What is a bacteriostatic drug that is used to treat VRE (vanco-resistant E. faceium), complicated skin/ sturue infection by methicillin-susceptible S. aureus or S. pygoenes?
Quinupristin- Dalfopristin (synecrid)
Quinupristin- Dalfopristin (synecrid) has what main AE?
Muscle and joint pain
What does Quinupristin- Dalfopristin (synecrid) inhibit?
P450 3A4 inhibitor
What is a better choice for vanco-resistant E. faecium?
Linezolid
What else is Linezolid used for?
no socomial pneumonia due to S. aureus
MRSA or S. pneumoniae
skin/ sturue infection
Gram + CAP
What is linezolid bacteriostatic against?
enetrococci and staph
What is linezolid bactericidal against?
strept
how is linezolid excreted?
Urine
What are concerning side effects of linezolid?
thrombocytopenia
HTN crisis if combined w/ MAOI, adrenegic and serotonergic drugs
What is mupirocin affective against?
gram positive cocci
what can you use mupriocin for?
topical treatment of skin
ex- impetigo
