Shared Flashcard Set

Details

Antibiotics2C
N/A
109
Medical
Graduate
07/11/2010

Additional Medical Flashcards

 


 

Cards

Term
What are examples of systemically used aminoglycosides?
Definition

gentamicin

tobramycin

amikacin

Term
What are examples of topically used aminoglycosides?
Definition
neomycin
Term
What is the activity of aminoglycosides?
Definition
bactericidal, concentration dependent
Term
What is the major use of aminoglycosides?
Definition
major use for over 30 yrs of AG is g-aerobic bacilli
Term
What can aminoglycosides be used synergistically with and what for?
Definition

synergistic bactericidal combination of AG and beta-lactam or vancomycin (inhibition of cell wall synthesis permits increased entry of AG into cell)

 

used for enterococcal endocarditis (ineffective vs. VRE)

 

used for pseudomonas (AG plus antipseudomonal penicillin or ceftazidime)

Term
What are AGs ineffective against?
Definition
anaerobes
Term
AGs are the DOC for treatment of endocarditis caused by what two bacteria?
Definition
E. faecalis and non-VRE E. faecium
Term
What is the DOC to treat endocarditis caused by E. faecalis and non-VRE E. faecium
Definition
penicillin G or ampicillin combined with gentamicin or streptomycin
Term
Gentamicin is the most often used AG for synergism with penicillins vs what three bacteria?
Definition

enterococci

streptococci

staphylococci

Term
What is the major advantage of tobramycin?
Definition
major advantage is activity (2-4 times as active) against some strains of P. aeruginosa that are resistant to gentamicin
Term
What is the major use of amikacin?
Definition
empiric therapy of nosocomial aerobic gram- bacillary infections where significant  gentamicin resistance exists
Term
Neomycin is used topically for minor soft tissue infections combined with what two drugs?
Definition

bacitracin

polymyxin

Term
Why should topical preperations of neomycin be avoided?
Definition
neomycin may be highly sensitizing and cause dermatological reactions
Term
AGs and CSF entry?
Definition
poor CSF entry even with inflammation; levels attained (20-25% of serum) are inadequate for meningitis
Term
How are AGs excreted?
Definition

excreted entrirely through glomerular filtration

half life of 2-3 hr; greatly increased in renal disease and required dosing adjustment

Term
Dosing regimens for AGs?
Definition
individualization of dosing regimens is advised due to the low (narrow) therapeutic index
Term
What is the most frequent cause of drug induced contact dermatitis?
Definition
neomycin - 8% incidence
Term
What are the characteristics of ototoxicity caused by AGs?
Definition

cochlear

vestibular

may be reversible if toxicity is mild, but extensive damage is usually irreversible

Term
What are predisposing factor for ototoxicity of AGs?
Definition
concurrent ototoxic drugs
Term
Which AG is more likely to affect vestibular function?
Definition
gentamicin
Term
What is usually assocatied with nephrotoxicity of AGs?
Definition
elevated trough serum levels of AGs
Term
Is renal impairment reversible?
Definition
may be reversible on d/c
Term
What is a predisposing factor for nephrotoxicity when using AGs?
Definition
concurrent nephrotoxic drugs
Term
tobramycin solution for inhalation is indicated for...
Definition
management of cystic fibrosis patients with P. aeruginosa infections
Term
What are the two main sources of tetracyclines?
Definition

tetracycline

doxycycline

Term
How are tetracyclines (esp doxycycline) classified?
Definition
long acting, lipophilic, hepatic elimination, bid dosing
Term
What are tetracyclines spectrum of activity?
Definition
broad spectrum bacteriostatic
Term
Tetracyclines have good activity against...
Definition

good activity vs. unusual spp.

intracellular organisms (highly active vs. spirochetes, mycoplasma, chlamydia, and rickettsia)

Term
What interaction can tetracyclines have that decreases their absorbance?
Definition
Chelate with divalent and trivalent cations to form insoluble complexes which are not absorbed (dairy products, mineral and vitamin supplements, antacids, cathartics)
Term
Food greatly reduces the availability execpt for what two drugs?
Definition

minocycline

doxycycline

Term
Describe tetracycline distribution into the CSF and placental barrier?
Definition

Poor entry into CSF even in inflammation; not indicated for meningitis

Crosses placental barrier and undergoes permanent sequestration in newly forming bone and teeth

Term
How is doxycycline eliminated?
Definition
Active biliary excretion and enterohepatic circulation (reabsorption); doxycycline half life unchanged in renal disease
Term
What tetracycline is used for acne vulgaris?
Definition

oral tetracyclines, low-dose, long-term

used in chronic, severe cases of acne vulgaris

no serious toxicity since doses are low

Term
What tetracycline is used in Lyme Disease (Borrelia burgdoferi)?
Definition

doxycycline

DOC for tx of early stage of Lyme Disease

Term
What is the DOC for relapsing fever (Borrelia recurrentis)?
Definition
tetracycline or doxycycline
Term
What is the DOC for urogenital infections caused by C. trachomatis?
Definition
doxycycline is the DOC for STDs (like non-gonococcal urethritis)
Term
For PID (salpingitis) what must you provide coverage for and with what drugs?
Definition

Gonococcus (cephalosporin)

C. trachomatis (doxycycline)

Term
What respiratory infection is doxycycline the DOC for?
Definition
atypical pneumonias (Mycoplasma, Chlamydia); however in vitro activity of doxycyclines is less than that of the macrolides
Term
What rickettsial infections is doxycycline the DOC for?
Definition

Rocky mountain spotted fever

typhus

Term
What tetracycline is the DOC for Vibrio infections and what are two example of vibrio infections?
Definition

doxycycline

cholera, gastroenteritis

Term
Tetracyclines are the DOC for anthrax (B. anthracis) - how are they used?
Definition

treatment of inhalational anthrax

treatment of cutaneous anthrax

prophylaxis

 

Term
Demeclocycline is used for...
Definition
management of syndrome of inappropriate  antidiuretic  hormone relases (SIADH)
Term
Explain how tetracyclines are incorporated into bone and teeth and what this causes?
Definition
Dose-dependent incorporation into growing teeth, producing a yellow brown discoloratoin of enamel and possible faulty enamel formation
Term
Explain how tetracyclines can cause deposits in crown of anterior teeth?
Definition
Crown formation complete by 6-7 years, high risk of permanent teeth discoloration when used in children less than 8 years (least likely to occur with doxycycline but should avoid all tetracyclines in children less than 8 years and in pregancy)
Term
Tetracyclines can cause temporary cessation of bone growth or bone deformity so what does this mean?
Definition
contraindicated in pregnant or nursing women or in children < 9 years
Term
What tetracycline must be taken on an empty stomach?
Definition
tetracycline
Term
What two tetracyclines must be taken with meals?
Definition
doxycycline and minocycline
Term
Doxycycline may necessitate administration with meals because...
Definition
GI irriration and nausea
Term
What should not be given for at least 2 hrs after dosing?
Definition
 no antacids, bismuth subsalicylate, vitamins, or mineral supplemants
Term
Should tetracyclines be taken with a full glass of water and be given at bedtime?
Definition
take with a full glass of water, do not give at bedtime
Term
Tigecycline
Definition
no affected by the two major tetracycline resistance mechanisms (ribosomal binding site alteration, active efflux); considered bacteriostatic
Term
What is tigecycline approved to treat?
Definition
complicated skin/skin structure infections (MRSA), complicated intraadbdominal infections (anerobes), CAP
Term
What are two common macrolides?
Definition

azithromycin

erythromycin

Term
Is erythromycin bacteriostatic or bactericidal?
Definition
bacteriostatic
Term
What is erythromycin used to treat?
Definition
gram + cocci: used as an alternative for penicillin allergic patients
Term
What bacteria is erythromycin active against and what is it inactive against?
Definition

active vs group A and B streptococci, S. viridans, and penicillin-sensitive S. pneumoniae

 

ineffective vs. enterococci

 

active vs C. diptheriae and Bordatella pertussis (whooping cough)

Term
What intracellular organisms is erythromycin active against?
Definition
Legionella pneumonphila, mycoplasmas (M. pneumoniae, U. urealyticum), chlamydiae (C. pneumoniae)
Term
Azithromycin has superior activity versus what?
Definition
Mycoplasma, Chlamydia, H. influenzae
Term
Either azithromycin (A) or erythromycin (E) is the DOC for...
Definition

-pneumonia caused by Chlamydia, Mycoplasma, or Legionella (A)

-whooping cough (Bordatella pertussis, E)

-diptheriae (C. diptheriae; E + antitoxin)

-PID due to C. trachomatis (A); cephalosporin or flouroquinolone for gonoccocal coverage

Term
What is used to treat pneumonia caused by Chlamydia, Mycoplasma, or Legionella?
Definition
azithromycin
Term
What is used to treat Bordatella pertussis (whooping cough)?
Definition
erythromycin
Term
What is used to treat diptheriae (C. diptheriae)
Definition
erythromycin + antitoxin
Term
What is used to treat PID due to C. trachomatis?
Definition
azithromycin - cephalosporin or flouroquinolone for gonococcal coverage
Term
What is used for prophylaxis for gonoccocal and chlamydial ophthalmia neonatorum
Definition
erythromycin topical 5% ointment
Term
What is erythromycin's active form (base) inactivated by?
Definition
inactivated by acid, so use delayed release (enteric coated) tablets
Term
Chemical modification of base (erythromycin)?
Definition

ethylsuccinate ester

estolate

Term
Best availability of erythromycin is when?
Definition
when taken in fasting state, except for stearate which should be taken with meals
Term
Dosing of macrolides?
Definition

tid

qid

Term
azithromycin dosing?
Definition

new tablets may be taken without regard to meals

once daily dosing

Term
ADR of macrolides
Definition
high TI
Term
Describe some erythromycin GI side effects and why they exist:
Definition
nausea, diarrhea, cramps; dose related effects attributed to agonist effects at motilin receptors
Term
Describe the toxicity associated with estolate?
Definition
cholestatic hepatitis (probably safe in children, estolate offers no therapeutic advantage and should be avoided in adults)
Term
Macrolides and cardiac side effects?
Definition

-may prolong the QT interval

-erythromycin has been associated with rare cases of torsades

Term
Erythromycin and drug interactions?
Definition
drug interactions due to inhibition of P450 system
Term
Which macrolide has the least amount of P450 inhibition?
Definition
azithromycin
Term
What is telithromycin used for?
Definition
developed specifically for treatment of community-acquired respiratory tract infections caused by both common and atypical pathogens, including resistant strains
Term
Telithromycin and resistance?
Definition
Telithromycin is unaffected by resistance mechanisms used against macrolides
Term
Telithromycin ADRs?
Definition

-strongly inhibits CYP3A4

-may prolong the QTc interval

-case reports of patients with jaundice, abnormal hepatic function, acute hepatic failure, and fulminant hepatitis leading to transplant or fatality

Term
What type of bacteria does clindamycin treat?
Definition
anaerobes (due to the association with pseudomembranous colitis, use of clindamycin is largely restricted to anaerobic infections)
Term
What is clindamycin also used to treat?
Definition
also used for mixed intraabdominal and female genital tract infections in combination with an AG
Term
How is clindamycin prepared for use in acne?
Definition
topical solution and gel
Term
Clindamycin and CSF distribution?
Definition
poor entry into CSF (about 10% of serum levels); not indicated for meningitis
Term
How is clindamycin used to treat anaerobic infections?
Definition
alternate DOC for infections due to B. fragilis; alternative to penicillin G for other anaerobes
Term
Clindamycin can also be used for anaerobic coverage for...
Definition
mixed aerobic-anaerobic infections
Term
Clindamycin can be used to treat two other things...
Definition

bone and joint infections (staphylococcal or anaerobic osteomyelitis)

acne vulgaris (topical preperations)

Term
Describe clindamycin antibiotic associated psedomembranous colitis (AAPMC)
Definition
incidence estimated at 1.9 per 1000 courses of clindamycin (1.5 for cephalosporins, 2.1 for ampicillins); incidence of significant lincosamide-induced colitis ranges from 0.1-10%
Term
What are the sxs of AAPMC?
Definition
profuse, watery diarrhea (10-20 stools/d); blood and mucous may be present in the stool (5-10%), intestinal lesions produced are covered by a pseudomembrane
Term
mechanism behind AAPMC?
Definition
superinfection of bowel by C. dificile, and production of two extracellular toxins (enterotoxin and cytotoxin) which causes the colitis
Term
What is the DOC for AAPMC?
Definition
DOC is po metronidazole
Term
What is the alternative agent for eradicating C. dificile?
Definition
po vancomycin (reserve for cases not responsive to two courses of  metronidazole or in life threatening colitis)
Term
What drugs are contraindicated in the treatment of AAPMC?
Definition
intestinal antimotility drugs
Term
What bacteria are chloramphenicol used to treat?
Definition
virtually all obligate anaerobes are suseptible (good activity vs Rickettsia spp.)
Term
CSF penetration of chloramphenicol?
Definition

CSF levels about 20-50% of plasma levels in the presence of uninflamed meninges, and about 45-90% of plasma levels in the presence of inflamed meninges; formerly used for empiric therapy of meningitis in combination with ampicillin

 

brain tissue levels about 9 times that of plasma - treat brain abcesses

Term
Does chloramphenicol have a low or high TI?
Definition
low TI; reserved only for serious infections for which less toxic agents are ineffective or contraindicated
Term
Chloramphenicol is alternative DOC for:
Definition
rickettsial infections in pregnancy or tetracycline allergy; for non-pregnant individuals > 8 yrs in the absence of allergy, doxycycline is the DOC for Rocky Mountain Spotted Fever
Term
What drug is useful in the treatment of epiglottitis, septic arthritis, or osteomyelitis due to H. infuenzae in penicillin allergic patients?
Definition
chloramphenicol
Term
What is the ADR of chloramphenicol?
Definition
narrow TI
Term
The narrow TI can causes?
Definition

-reversible bone marrow depression

-aplastic anemia

-"gray" syndrome in full-term neonates and premature infants

Term
Describe the aplastic anemia associated with chloramphenicol...
Definition

-pancytopenia with aplastic marrow

-idiosyncratic, neither dose nor duration related

-poor prognosis, high % fatalities; only tx is bone marrow transplant

Term
Describe "gray" syndrome associated with chloramphenicol use...
Definition

unaltered drug accumulates to toxic levels (deficient glucuronidation, low GFR), causing inhibition of mitochondrial oxidative phosphorylation

 

usually reversible is drug d/c at onset of sxs

Term
What is the main affect of mupirocin?
Definition
inhibits bacterial proteins synthesis
Term
What are the dosage forms and uses of mupirocin?
Definition

2% ointment for dermatologic use (not for ophthalmic use): indicated for topical tx of impetigo due to S. aureus, beta-hemolytic strep, and S. pyogenes

 

2% ointment for intranasal use: indicated for eradication of nasal colonization with methicillin-resistant S. aureus in adult patients and healthcare workers

Term
What does Quinopristin/dalfopristin affect?
Definition
combination is synergistic, affecting both the early (dalfopristin) and late (quinupristin) stages of proteins synthesis
Term
What is Quinupristin/dalfopristin used to treat?
Definition
serious or life threatening infections associated with vancomycin-resistant E. faecium bacteremia (VREF; bacteriostatic)
Term
ADR of quinupristin/dalfopristin?
Definition
administered by IV infusion; most frequent ADR is at the infusion site
Term
DI of quinupristin/dalfopristin
Definition
potent inhibitor of CYP3A4
Term
Linezolid approved indications?
Definition

-VRE E. faecium including concurrent bacteremia

complicated skin/skin structure infections, including -diabetic foot infections, without concominant osteomyelitis

-CAP: PSSP, MSSA, DRSP

-preferred DOC for VISA and VRSA

-preferred DOC for PRSP pneumonia

Term
ADR of linezolid?
Definition

thrombocytopenia

myelosuppression

Term
DI of linezolid?
Definition

-weak, reversible, nonselective MAOI

-potential DI with adrenergic and serotonergic agents

-interaction with tyramine containing foods may cause hypertension

-reports of serotonin syndrome with concurrent use of serotonergic agents

Supporting users have an ad free experience!