Antibiotics Flashcards
respiratory fluoroquinolones
levofloxacin (Levaquin), moxifloxacin (Avelox), Gemifloxacin (Factive)
which drugs warrant not using any drug from fluoroquinolone class
class 1 & 3 antiarrhythmics including amiodarone, disopyramide, quinidine, bepridil, sotalol, all drugs prolonging QT interval (CV risk, arrhythmia, even fatal). glucocorticoids (increased tendon rupture risk)
which drugs warrant not using levofloxacin
NSAIDS (increased CNS stim, seizures)
use of respiratory fluoroquinolones in pneumonia (levo, moxiflo, gemiflo -xacin)
first line for comorbidities/risks (diabetes, chronic heart/liver/lung disease, alcoholism, malignancies, asplenia, immunosuppressed, DRSP risks). give 7-14 days
when are respiratory fluoroquinolones used in chronic bronchitis exacerbations?
moderate exacerbations that may require hospitalizations or patients who dont respond to first line therapy
when are respiratory fluoroquinolones used in UTI?
for patients who are not able to tolerate first line therapy TPM/SMX, Bactrim, Septra). can ONLY use levofloxacin from this subcategory (still 24% resistance)
what groups cannot have fluoroquinolones or should avoid them if possible?
pregnant women. breast feeding. children (joint, cartilage ADRs). except cipro (non resp-fluro) for 2nd line complicated UTI or pyelonephritis in kids. treated diabetics. patients with prolonged QTc interval or taking drugs that prolong it. seizure prone patients (severe cerebral atherosclerosis, epilepsy, alcohol abuse, theophylline use, antipsychotic use). dont use for myasthenia gravis (black box). dont use if taking corticosteroids (black box tendon rupture higher risk) (those who are dialysis, elderly, heart/kidney/lung transplant also higher risk of this). they can be used cautiously in renal failure, but need to adjust dose (except moxifloxacin no dose adjust).
can the fluoroquinolones be used for chlamydia or gonorrhea?
no longer use in gonorrhea d/t resistance. levofloxacin and ofloxacin (non resp-fluoro) 2nd line for chlamydia (these can also be used in epidiymitis from enteric bacteria, if gonorrhea negative)
can fluoroquinolones be used for skin/tissue infections?
although approved, avoid because of resistance concerns. beta lactams usually work if not exposed to fresh water
can fluoroquinolones be used for diarrhea?
yes, the NON-respiratory ones are first line for travelers diarrhea and severe diarrhea not caused by antibiotics (6+ stools/day and/or temp 38.8+, tenesmus, blood, or fecal leukocytes)
can fluoroquinolones be used for sinusitis?
levo, moxiflo can be used for adults allergic to beta lactams (ISDA cautions against use d/t cost, resistance). levo should only be used in children with type 1 allergy to beta lactams (off label) after clindamycin/cefixime combo tried first (AAP caution against use d/t cost, toxicity, resistance)
considerations if fluoroquinolone is right or not
cost (brand name ones very costly, cipro and levo have generic), avoiding resistance (cipro & levo only PO abx available not resitant to p. aeruginosa, resp-fluros enhanced gram + activity not resistant to highly-penicillin resistant strains of s. pneumoniae which are also resistant to 4 other abx classes; gemiflo and moxiflo much higher AUC:MUC ratios so good for URI), ADRs, drug interactions, treated diabetics (avoid if possible), patients with prolonged QT interval/drugs that prolong it, children, pregnant women
what labs are needed for fluoroquinolones?
renal/hepatic/hematopoietic function if on prolonged therapy. baseline renal fxn labs before starting a drug in this class. baseline EKG before starting moxifloxacin (if syncope, repeat and withhold drug until view, could be lethal torsade de points). if on warfarin, closely monitor INR. if on theophylline or cyclosporine, get blood levels plasma concentrations of these drugs (metabolized by CYP3A4, which is inhibited by fluruouqunolones)
patient education for fluoroquinolones related to timing, food, drink
cipro take 2 hours after a meal and dont take with dairy. norfloxacin dont take with dairy. take all with full glass water to avoid dehydration -> crystallurea. 2-4/6 hour gap with drugs that can chelate them, including antacids, bismuth subsalycate, calcium, mag, iron, sucralfate, sevalamer, zinc
patient education for fluoroquinolones related to ADRs that warrant telling provider and/or discontinuing
d/c at any sign of hypersensitivity (hives, dyspnea, itching), as anaphylaxis and Stephen johnsons can even happen at first exposure. if diabetic, monitor BG carefully, report hypos immediately. if tender/inflamed tendon/s, immediately d/c and tell doc, rest, no exercise of effected joint. withhold drug and report any blister, rash, or itching (can cause photosensitivity or phototoxicity); recovery prolonged and recurs if exposed again to sunlight before recovering. d/c at first sign of jaundice (hepatitis, hepatonecrosis, liver failure). tell doc if diarrhea with blood/pus/mucus (c diff possible). rare CNS stimulation (sleep disorder, vertigo, nervous, sleeplessness, tired, bad dreams, restless, confusion, hallucination, toxic psychosis, seizure, increased ICP), but dose dependent and typically resolve with continued use (slight mag deficient amplify effects; higher risk in elderly, dialysis).
patient education for fluoroquinolones related to general cautions/precautions
can cause dizziness/light-headedness, dont drive/hazardous activities until know effects. adequate fluid to have UO of 1500 ml/d to avoid crystallurea. minimize urinary alkalizers like citrus drinks. avoid baking soda, antacids. avoid direct sun/tanning/sun lights from first dose till several days after last dose (photosensitivity, phototoxicity). common adverse effects: abdominal pain, nausea, altered taste, diarrhea.
bactericidal drugs
kill target organisms. include aminoglycocydes, cephalosporins, penicillins, quinolones
bacterostatic drugs
inhibit or delay bacterial growth, replication. include tetracclines, sulfonamides, macrolides
bactericidal and bacterostatic drugs
can be either depending on dose, duration of exposure, state of invading bacteria. includes aminoglycocides, flouroquinolones, metronidazole (they have concentration-dependent killing; their rate of killing increases as drug concentrations increase)
causes of drug resistance
recurrent abx use, overuse of broad spectrum; <2y or >65y, daycare, exposed to young children; multiple medical comorbidities; immunosupression
antimicrobial drug resistance
every class has resistant organisms; local resistance patterns can be IDd by monitoring antibiogram of local lab; vaccination with pneumococcal vaccine has decreased resistance
how do beta lactams work
inhibit synthesis of peptoglidican bacterial cell wall
beta lactams combined with what beta-lactamase inhibitors to broaden spctrum
clavulanate, slbactam, tazobactam
natural penicillins are sensitive agsints (effective for) which organisms
streptococcus, some enterococcus, some non-penicillinase producsing staph
aminopenicillin activitypa
more activity against gram negative bacteria due to enhanced ability to penetrate outer membrane organisms. gram negative urinary and GI pathogens e coli, proteus mirabalis, salmonella, some shigella, enterococcus faecalis. active against common gram negative respiratory pathogens moraxella catarrhalis and h. influenzae type B
penicillin PK
well absorbed from GI tract, but many less stable in acid (dicoxacillin, amoxicillin better than ampicilin) ; bound to proteins with good distribution to most tissues; small amount met, most excreted as unchanged drug in urine ; probenecid prolongs half life and increases risk for toxicity
