Antimicrobial Therapy Flashcards
Cocci arrangements
clusters, chains and pairs
Bacilli arrangement
rods
Spirochetes arrangement
coiled
Bacterial cell wall composition
peptidoglycan
Gram (+) vs Gram (-) bacteria
Gram (+): thick peptidoglycan layer, many have teichoic acid, no periplasmic layer, no LPS, no outer membrane, primarily produces exotoxins, has flagella, tough
Gram (-): thin peptidoglycan layer, no teichoic acid, outer membrane is present, periplasmic space, has LPS, has flagella, produces endotoxins, not very tough
Gram (+) organisms
Staphylococcus- cocci in clusters
streptococcus- coccus in chains
enterococcus-cocci in chains
listeria- rods
Gram (-) organisms
Neisseria- cocci
Rod: escherichia, salmonella, klebsiella, pseudomonas, proteus, haemophilus, legionella
Anaerobic organisms
clostridium, bacteroides, peptostreptococcus
Atypical organisms
chlamydiae, mycoplasmas, rickettsiae
Common organisms found on SKIN
staphylococcus aureus and streptococcus pneumoniae
Common organisms found in the ENTERIC (gut)
escherichia coli, salmonella, klebsiella, proteus
Common organisms found in the RESPIRATORY tract
haemophilus influenza, legionella
Common organisms found in the CNS
listeria, neisseria, haemophilus
Common organisms found in the HEART
staphylococci, streptococci, enterococci
Common organisms found in the GENITOURINARY tract
neisseria gonorrhea, escherichia coli, proteus
Time dependent
optimal effect when the antibiotic concentration remains above the MIC in any one duration of the dosing interval
Concentration dependent
optimal effect when concentrations are appreciably above the MIC for a given organism (up to a specific level)
Bacteriostatic
INHIBITION of bacterial growth
Bacteriocidal
KILLING of the bacteria
Beta-lactams
the beta-lactam ring inhibits bacterial cell wall synthesis
bacteriCIDAL
time dependent killing
Penicillins
Penicillin VK
Amoxicillin
Dicloxacillin
Amoxicillin-Clavulanate
Penicillin VK
Veetids
oral- tab and powder for reconstitution
kids: 25-75 mg/kg/day in divided doses q6-8h
adults: 125-500mg PO q6-8h
covers mostly gram (+) (enterococci and streptococci)
indications: pharyngitis, otitis media, skin/soft tissue infections, rheumatic fever
AEs: melanoglossia, mild GI effects: n/v/d
time dependent and bactericidal
take on empty stomach 1 hr before or 2 hrs after meals
Amoxicillin
Amoxil
Oral- cap and powder for recostitution
kids: 25-50mg/kg/day in divided doses q8h
adults: 250-500mg PO q8-12h
covers gram (+) and some gram (-)
indications: pharyngitic, lower resp. tract infections, endocarditis prophylaxis, ENT/skin and soft tissue infections, animal bites
AEs: n/v/d (take w/ food)
time dependent and bactericidal
Pearls: give ATC, shake suspension well - can mix w/ formula, milk, fruit juice, water, ginger ale, cold drinks
Amoxicillin-Clavulanate
Augmentin
Oral: Tabs and susp.
adults: 500mg q8-12h or 875mg q12h or 2g q12h
kids (<40kg): 20-45mg/kg/day in divided doses bid-tid
gram(+) and gram(-)
indications: sinusitis, otitis media, lower resp. tract infections, community acquired pneumonia, UTI, bite wounds
AEs: diarrhea, N/V, abdominal distress, hepatic dysfunction
Pearls: adjust in renal dysfunction, give ATC,
take w/ food to increase absorption and decrease stomach upset
Dicloxacillin
oral: capsule
125-500mg q6h
Only covers staphylococcus epidermis and aureus (MSSE and MSSA)
Indications: skin/soft tissue infections, bite wounds, impetigo
AEs: abdominal pain, diarrhea, nausea
Pearls: take 1 hr before or 2hrs after meals w/ at least 120ml of water, take ATC to prevent variations in peak and trough serum levels,
Drug interaction: warfarin (lowers INR)
Cephalosporins
4 generations
some cross sensitivity w/ pcn allergy
none of them cover enterococci
Cephalexin
Keflex- 1st gen
Oral: cap and susp. for recon
Adult: 250-1000mg q6h or 500mg q12h (max 4g/day)
Kids: 25-100mg/kg/day in divided doses q6-8h (max: 4g/day)
Covers streptococci and staphylococcus aureus w/ some gram (-) coverage
Indications: impetigo, skin/soft tissue infections, pharyngitis, UTI, otitis media
AEs: ab. pain, diarrhea, dyspepsia
Pearls: dose adjust-renal impairment, give w/o regard to food but if GI distress- take w/ food, give ATC, associated w/ elevated INR
drug interaction: metformin (increase metformin serum conc.)
Cefaclor
Ceclor- 2nd gen.
Oral: tab, cap, susp for recon.
Adult: 25-500mg q8h or 500mg q12h for ER
Kids: 20-40mg/kg/day divided q8-12h
Covers streptococci and staphylococcus aureus w/ expanded Gram (-) coverage and anaerobic coverage
Indications: bronchitis, otitis media
AEs: diarrhea (use caution in hx of GI diseases), increase in transaminase/LFTs (monitor if on long term tx)
Pearls: dose adjust in renal impairment, give ATC, take w/ or w/o food, shake susp. well
ER tabs: don’t chew/crush/split and give w/ or w/in 1 hr of food
Ceftriaxone
Rocephin- 3rd gen.
IV or IM (not orally)
Adult: 1-2g q12-24h
Kids: 50-100mg/kg/day in 1-2 divided doses q12-24h
Covers gram (+) and gram (-) orgs
Indications: endocarditis, gonorrhea, GI infections, meningitis
AEs: diarrhea, skin tightness and warm sensation at injection site (IM), pancreatitis
Contraindicated in hyperbilirubinemic neonates (<28 days old) and/or contraindicated w/ IV calcium
Concurrent renal/hepatic impairment: no more than 2g/day
Cefepime
Maxipime-4th gen.
IV
Adults: 1-2g q8-12h
Kids: 50mg/kg/dose q8-12h
Covers gram (+) and gram (-) w/ expanded coverage of orgs w/ multi-drug resistance patterns
Indications: intra-abdominal infections, pneumonia, UTI, meningitis
AEs: positive direct Coombs test, transaminitis/increase LFTs, hypophosphatemia, neurotoxicity
Pearls: dose adjust in renal impairment
Protein Synthesis Inhibitors- drug classes
aminoglycosides
tetracycines
macrolides
clindamycin
Aminoglycosides
Binds 30S ribosomal subunit
bactericidal, conc. dependent
Gentamycin, Tobramycin, Neomycin
Gentamycin
IV or IM
2-5mg/kg/day divided doses q8h
Covers mostly gram (-)
Indications: endocarditis, meningitis, intra-abdominal infections, sepsis/septic shock, synergy w/ other antibiotics
AEs: nephrotoxicity, neurotoxicity- ototoxicity, neuromuscular toxicity
Pearls: TDM required, avoid in pregnancy, dose adjust in renal impairment
Tetracycline
Binds to 30S ribosome subunit
bacteriostatic and time dependent
Doxycycline, minocycline, demeclocycline
Doxycycline
Oral: IR and ER formulations
1000-200mg/day in 1-2 divided doses
Covers some gram (+) and gram (-), some anaerobics, atypical orgs.
Indications: pneumonia, Rocky Mountain Spotted fever, Chlamydia, Lyme disease
AEs: GI inflammation/ulceration, intracranial hypertension, photosensitivity, tissue hyperpigmentation, hepatotoxicity
Pearls: things that can decrease serum conc: chronic alcohol use, taking w/ high-fat meal/milk, taking w/ iron/calcium
may cause tissue hyperpigmentation/tooth enamel hypoplasia or permanent tooth discoloration when used during tooth development (last half of pregnancy, infancy, kids <8)
**good option for people that can’t take azithromycin
Macrolides
bind 50s ribosome subunit
Bacteriostatic
time dependent or conc. dependent
azithromycin, erythromycin, clarithromycin, fidaxomicin
Azithromycin
Zithromax
oral
1-2g single dose (chlamydia), 500mg diaily, or 500mg on day 1 then 250mg days 2-5
Covers some gram (+) and gram (-) and atypical orgs
Indications: pneumonia, sinusitis, chlamydia, H. pylori infections, pharyngitis, pelvic inflammatory disease
Pearls: inhibits P-gp - avoid w/ amiodarone
AEs: loose stool, vomiting, nausea, diarrhea, QT-prolongation
Erythromycin
E.E.S 400 or Ery-Tab
Time dependent
Clarithromycin
Biaxin
Fidaxomicin
Dificid
Clindamycin info
Lincosamide
binds to 50S ribosomal subunit
bacteriostatic
time dependent
Clindamycin
Cleocin
oral and IV
Adults: 150-450mg PO q6h (600-2700mg/day in 2-4 divided doses)
Kids: 8-40mg/kg/day PO in 3-4 divided doses (20-40mg/kg/day in 3-4 divided doses)
Covers: expanded gram (+), anaerobic orgs
Indications: pneumonia, otitis media, bone/joint infections, intra-abdominal infections, lower resp. tract infections, skin/soft tissue infections
AEs: diarrhea, metallic taste (IV), black box warning: colitis
Pearls: use w/ caution in GI disease/mod-severe hepatic impairment
Metronidazole info
nitroimidazole pro-drug
bactericidal
conc. dependent
Effects org’s DNA: disrupts structure inhibiting replication
Metronidazole
Flagyl
oral and IV
250-750mg PO/IV q8h
Covers anaerobic orgs and parasites
Indications: amebiasis, bacterial vaginosis, intra-abdominal infections, trichomoniasis, giardiasis, C.diff associated diarrhea
AEs: HA, nausea, metallic taste, CNS related effects
black box warning: carcinogenic in mice- avoid unnecessary use
Pearls: IV form contains sodium, avoid alcohol during treatment and at least 3 days after- disulfiram-like reaction, dose adjust in severe hepatic impairment
Contraindicated in 1st trimester
Drug-drug interactions: warfarin (increased INR) lopinavir (inhibits metabolism and contains alcohol)
Sulfamethoxazole and Trimethoprim MOA
Sulfamethoxazole- inhibits conversion of PABA to dihydropteroic acid by inhibiting dihydropteroate synthase
Trimethoprim: prevents reduction of dihydrofolic acid to tetrahydrofolic acid by inhibiting dihydrofolate reductase
Combo is bactericidal
concentration dependent
Sulfamethoxazole and Trimethoprim
Bactrim
PO and IV
Bactrim DS: 160mg TMP/800mg SMX tabs - 1 tab q12h
Bactrim SS: 80mg TMZ/400mg SMX - 2 tabs q12h
IV: 80mg TMP/400mg SMX
Indications: UTI, pneuomcystis carinii jirovecii (PJP), nosocomial infections, otitis media
Covers: staphylococci and gram (-) orgs
AEs: n/v (take w/ food), rise in SCr, hyponatremia, crystaluria (drink lots of water), hyperkalemia (TMP looks like amiloride- K+ sparing diuretic)
Pearls: SMX metabolized by CYP2C8, TMP metabolized by CYP2C9 - drug interactions (warfarin, oral antidiabetic agents), avoid in 1st trimester, renal impairment, avoid in G6PD deficiency/sulfonamide allergy (skin rash/pruritus)
Nitrofurantoin MOA
activated by enzymatic reduction
damages bacterial DNA
Bactericidal
Conc. dependent
Nitrofurantoin
Macrobid: 100mg bid
Macrodantin: 50-100mg q6h
Covers: gram (+) and gram (-)
Indications: UTI
AEs: brown urine, optic neuritis and peripheral neuropathy, pulmonary toxicity, hepatic reactions
Pearls: take w/ food, avoid in G6PD deficiency, interacts w/ Mg2+ lowering effectiveness
Contraindications: pregnant women at term, CrCl<60 (relative), hx of cholestatic jaundice/hepatic dysfunction
Fluoroquinolones info
inhibits DNA gyrase and topoisomerase IV bactericidal Conc. dependent ciprofloxacin (Cipro) levofloxacin (Levaquin) moxifloxacin (Avelox)
Fluoroquinolones
Broad spectrum coverage: minimal gram (+), covers gram (-), atypical orgs (levofloxacin and moxifloxacin better resp. covering agent and moxifloxacin has expanded coverage)
Indications: UTI, endocarditis, prostatitis, pneumonia, STIs, GI/abdominal infections, resp. tract, bone, joint, soft tissue infections
AEs: GI upset (take w/ food), CNS effects (elderly), QT prolongation, hepatotoxicity, tendon rupture( >60, transplant pt, concomitant steroids), hypoglycemia, crystaluria (drink lots of water), photosensitivity
Pearls: avoid antacids/ iron/zinc (tri and divalent cations) decreases effectiveness- take 2hrs before or 6hrs after the drug
Black box warning: reserve for pts have no alternative tx options for acute exacerbation of chronic bronchitis, acute sinusitis, acute uncomplicated cystitis (UTI)
Ciprofloxacin
Cipro PO: 500-750mg q12h IV: 400mg q12h Pearls: dose adjust in renal impairment drug-drug interactions: Substrate of OAT3, P-gp/ABCB1, Inhibits CYP1A2 (moderate), CYP3A4 (weak)
Levofloxacin
Levaquin
PO or IV: 250-750mg q24h
dose adjust in renal impairment, minimal hepatic metabolism (fewer interactions)
Moxifloxacin
Avelox PO or IV: 400mg q24h not metabolized by CYP450 isoenzymes highest risk of QT prolongation **not used for UTI**
Bacteriostatic antibiotics
Tetracycline
Macrolides
Clindamycin
Bactericidal antibiotics
Beta-lactams: penicillins, cephalosporins Aminoglycosides Metronidazole Bactrim Nitrofurantoin Fluoroquinolones
Concentration dependent antibiotics
Aminoglycosides Macrolides Metronidazole Bactrim Nitrofurantoin Fluoroquinolones
Time dependent antibiotics
Beta-lactams: penicillins, cephalosporins
Tetracycline
Macrolides
Clindamycin
