Drugs for bacterial infections 2 Flashcards
What should you NOT compare on a C&S report?
the MIC of different classes of antibiotics
What are examples of tetracyclines?
tetracyclline, doxycycline, minocycline
are tetracyclines bacteriostatic or bactericidal?
bacteriostatic
What’s the MOA of tetracyclines?
inhibit protein synthesis w/ binding to 30S ribosomal subunit and blocking binding of aminoacyl transfer-RNA
What are ADRs of tetracyclines?
photosensitivity, GI intolerance, stain on developing teeth (<8yo), cannot take in pregnancy!
What do tetracyclines have a drug interaction with?
DI w/ polyvalent cations decreasing absorption – must take two hours before or after medications
When are tetracyclines reliable to use?
atypicals, plasmodium (malaria), rickettsia, spirochetes
When are tetracyclines moderate to use?
staph (MRSA), s pneumoniae
What can you not gram-stain b/c they lack a peptidoglycan layer?
atypicals
When are tetracyclines clinically utilized?
respiratory tract infections, SSTI, syphilis, PID (w/ cefoxitin), malaria prophylaxis, acne
When are tetracyclines your DOC?
tick-borne diseases, chlamydia
What are examples of macrolides?
erythromycin, clarithromcin, azithromycin
What’s the MOA of macrolides?
bacterioSTATIC
inhibit protein synthesis by binding to 50s ribosomal units, inhibiting translocation of peptidase chain
What do macrolides do that cause major DIs?
inhibit CYP450 clarithro and erythro only major DIs!
What are ADRs of macrolides?
GI effects (erythro is the worst), hepatic effects, Qtc prolongation
When are macrolides relibale?
atypicals, h. flu (NOT erythro), h. pylori (clarithro), mycobacterium avium
When are macrolides moderate?
s. pneumoniae, s. pyogenes
When are macrolides clinically utilized?
resp infections, atypical mycobacterial infections, traveler’s diarrhea (azi), SSTI if PCN allergic
When are macrolides your DOC?
chlamydia (azithromycin) H. pylori (clarithromycin –metallic taste)
What are examples of oxazolidinones?
linezolid and tedizolid
What’s the MOA of oxazolidinones?
bacterioSTATIC
inhibit protein synthesis by binding to 23S RNA of 50s subunit, preventing translation
How are oxazolidinones orally bioavailble?
100%
When should you be cautious with using oxazolidinones?
sympathomimmetics and SSRIs – weak MAO inhibitor and can cause serotonin syndrome
What are ADRs of oxazolidinones?
thrombocytopenia, peripheral and optic neuropathy, lactic acidosis
When are oxazolidinones reliable?
MSSA, MRSA, strep (resistant s. pneumoniae), enterococci (including VRE)
hospital based!
When are oxazolidinones moderate?
some atypicals
When are oxazolidinones clinically utilized?
infections caused by GPC (MRSA, VRE) like SSTIs, and hospital associated pneumonia
What’s clindamycin?
lincosamide
What’s the MOA of lincosamides?
inhibits protein synthesis by reversibly binding to 50S
What’s the oral bioavailability of lincosamides?
90%
What’s the eagle effect?
bacteria exposed to concentrations higher than optimal concentration survive more
What are ADRs of lincosamide?
GI intolerance (C. dif colitis)
When are lincosamides reliable?
many G+ anaerobes, plasmodium species (malaria)
When are lincosamides moderate?
s. aureus (MRSA) but not DOC, strep, G- anaerobes
When are lincosamides clinically utilized?
SSTIs, infections of oral cavity, anaerobic intra-abdominal infections, acne (topically)
What are folate antagonists?
sulfamethoxazole and trimethoprim
bactericidal combo!
What’s the MOA of folate antagonists?
sulfa = structurally similar to PABA and block incorporation of PABA
tri = prevents reduction of dihydrofolate to tetra by inhibiting enzyme
What’s folate antagonists bioavailability?
90-100%
How should you always prescribe folate antagonists?
1:5 ratio of TMP and SMX
What are ADRs of folate antagonists?
hypersensitivity, hematologic toxicity, hyperkalemia, obstructive uropathy
When is there a DDI with folate antagonists?
warfarin! displaces warfarin from albumin - higher conc in blood
When are folate antagonists clinically reliable?
h. flu, pneumocystis jirovecii, s. aureus (some MRSA), strenotrophomonas maltophilia
When are folate antagonists moderate?
enteric GNRS, s. pneumoniae, shigella, nocardia
When are folate antagonists clinically utilized?
UTIs, SSTIs, GI infections
When are folate antagonists your DOC?
stenotrophomonas maltophilia, nocardia, pneumocystitis jiroveci pneumonia
What’s the MOA of fluoroquinolones?
bactericidal!
MOA: Inhibit DNA gryase preventing DNA synthesis
What’s the oral bioavailability of fluoroquinolones?
80-100%
How are cipro/levo eliminated vs moxi?
renally versus hepatically
What are ADRs for fluorquinolones?
GI, headache, photosenstivity
rare: glycemic changes, seizures, prolongation of QT interval, arthralgias, Achilles tendon rupture, CNS
When are fluorquinolones contraindicated?
pregnant women and mostly children
What are some DIs of fluoroquinolones?
polyvalent cation binding & inhibits warfarin metabolism
When are fluoroquinolones reliable?
atypicals, enteric GNRs, H. flu, s. pneumoniae (NOT cipro)
When are fluoroquinolones moderate?
pseudomonas (levo/cipro), MSSA, anaerobes (moxi)
When are fluoroquinolones clinically utilized?
UTIs (NOT moxi), resp tract infections (NOT cipro), intra-abdominal infections w/ metronidazole, osteomyelitis
When are fluoroquinolones your DOC?
complicated UTIs (cipro/levo), severe pneumonia (not cipro)
What’s the MOA of metronidazole?
bactericidal!
disrupts DNA’s helical structure
90% orally available
What are ADRs of metronidazole?
GI effects, metallic taste, headache, dark urine
rare: peripheral neuropathy (prolonged use), seizures, SJS
What are DIs with metronidazole?
disulfuram-like reaction w/ EtOH; increases INR of warfarin
When is metronidazole reliable?
G- and G+ anaerobes
When is metronidazole moderate?
H. pylori
When is metronidazole clinically utilized?
addition of anerobic coverage, vaginal trichomoniasis, GI infections from protozoa
When is metronidazole your DOC?
mild-moderate C. dif
What’s the MOA of nitrofurantoin?
static or cidal depending on concentration!
reduced by flavoproteins to active intermediatese that inactivate/damage ribosomal proteins
In who can you not prescribe nitrofurantoin?
poor renal function patients (CrCl<50)
What are ADRs of nitrofurantoin?
GI effects
rare: peripheral neuropahty and pulmonary fibrosis (long term)
When is nitrofurantoin clinically good?
e. coli, staph saprophyticus
When is nitrofurantoin moderate?
citrobacter, klebsiellla, enterococci
When are nitrofurantoins clinically utilized?
uncomplicated UTIs
When is nitrofurantoin your DOC?
uncomplicated UTis and uncomplicated UTIs in pregnancy
What is can’t see, can’t pee, can’t climb a tree?
gonorrhea! can spread to their joints
What is trichomoniasis vaginitis?
anaerobic protozoan trophozoite – STD with malodorous, yellow-green discharge, dyspareunia, strawberry cervix
What’s the treatment for trichomoniasis vaginitis?
metronidazole
What’s syphillis?
treponema pallidum, spirochete
PAINLESS chancre followed weeks later by malaise, fever, pharyngitis, LAD, can go for years and cause inflammatory reaction in every organ
What’s the treatment for syphilis?
<1 year = benzathine PCN G
>1 year w/ no CNS ssxs = benzathine PCN G weekly x 3 weeks
neurosyphilis = IV every 4 hours 10-14 days
What should you treat pharyngitis with if PCN allergy w/o anaphylaxis?
keflex
What should you treat pharyngitis with for PCN allergy WITH anaphylaxis?
macrolide or clindamycin
What’s important to ask when looking at pneumonia treatments?
community or hospital acquired?
outpatient or inpatient treatment?
healthy w/no risk for MRSA/pseudomonas?
comorbidities?
LOTS of bacteria that can cause pneumonia!
How do you treat community acquired pneumonia outpatient in a healthy patient?
doxycycline, clarithromycin, azithromycin
How do you treat community acquired pneumonia outpaitent w/ comorbidites?
- macrolide
- doxy AND beta-lactam (augmentin, cefuroxime, cefpodoxime)
- fluoroquinolones (levaquin, moxifloxacin)
What organisms commonly cause TSS?
staph aureus, coagulase-neg staph, strep, mycoplasma
How do you treat TSS?
supportive!
staph = nafcillin or oxacillin AND clindamycin (MSSA), vancomycin AND clindamycin (MRSA)
strep = PCN G AND clindamycin, vancomycin AND clindamycin (PCN allergic), ceftriaxone AND clindamycin
REVIEW: How do you treat hidradenitis suppurativa?
stage 1 = topical benzoyl peroxide or clindamycin
stage 2 = above + Doxycycline (oral abx)
stage 3 = derm referral
REVIEW: how do you treat erysipelas?
IV dicloxacillin or 1st gen cephs
(I have penicillin on mine but she doesn’t have that on hers)
Covering anaerobes : CAMP MUC
Clindamycin
Augmentin
Metronidazole
Piperacillin/tazobactam
Moxifloxacin
Unasyn
Carbapenems
