Antimicrobials Flashcards
1
Q
ampicillin: class + use
A
- class
- broad spectrum, beta lactam ABX
- 2nd generation penicillin
- use
- GI/GU
- dental
- endocarditis prophylaxis
2
Q
ampicillin: MOA
A
- Bactericidal
- Binds to penicillin binding protein (PBP)
- activates autolysins → enzymatic destruction of cell wall
- inhibit enzyme (transpeptidases) needed for cell wall synthesis and integrity
3
Q
ampicillin: PK
A
- E1/2t: 2 hrs (can be up to 20 hrs in RF)
- PB: 20%
- Elimination: excreted 90% unchanged in the urine
4
Q
ampicillin: SE
A
- highest incidence of rash among penicillins (7-10 days after therapy) - mostly due to impurities in the commmercial preparation of the drug and not true allergic reaction to drug
- anaphylaxis
- diarrhea, GI upset
- drug induced SLE
- interstitial nephritis
5
Q
ampicillin: cautions/contraindications
A
- hypersensitivity to PCN; consider cross reactivity w/ cephalosporins
- may potentiates warfarin
- ↓ dose in RF
6
Q
ampicillin: dose
A
- 2 grams IV 30 min preop: administer over 10-15 minutes (rapid infusion can cause seizures)
7
Q
cefazolin (ancef): class + use
A
- class
- Broad-spectrum, ß lactam ABX
- 1st generation cephalosporin
- use
- SSI prophylaxis in CV, ortho, biliary, pelvic, intraabdominal (favorable therapeutic index)
8
Q
cefazolin: MOA
A
- bactericidal
- binds to penicillin binding protein (PBP)
- activates autolysins → enzymatic destruction of cell wall
- inhibits enzyme (transpeptidases) needed for cell wall synthesis and integrity
9
Q
cefazolin: PK
A
- E ½ life: 2 hrs
- PB: 80% (high)
- Excretion: 80-100% unchanged in urine
10
Q
cefazolin: SE
A
- ***favorable therapeutic index*** (low toxicity, highly effective)
- Hypersensitivity
- anaphylaxis (1% - 2% cross reactivity with PCN allergy)
- Superinfection (C. diff)
- Thrombophlebitis @ IV site (uncommon)
- Hemolytic anemia (very rare)
11
Q
cefazolin: cautions/drug interactions
A
- CAUTIONS
- hypersensitivity
- cross reactivity with penicillin (1-2%) and other cephalosporins
- renal failure → dose adjust
- crosses placenta
- hypersensitivity
- drug interactions
- ETOH use (if going home with prescription) → disulfiram like reaction
- Probenecid (gout drug) → prolong DOA
12
Q
cefazolin: dose
A
- 1-2 grams IV 30 min preop, ↓ dose in RF
13
Q
gentamycin: class + use
A
- class
- broad-spectrum aminoglycoside ABX
- use
- pleural, ascitic, synovial infections
14
Q
gentamycin: MOA
A
- bactericidal
- works on 30s ribosomal subunit
- blocks the initiation of protein synthesis/premature termination of protein synthesis/abnormal protein formation in bacterial cells
15
Q
gentamycin: PK
A
- E1/2t: 2 – 3 hrs (20-40 fold ↑ in RF)
- Very positively charged
- PB: < 30% (poor)
- Elimination: almost 100% renal excretion unchanged
16
Q
gentamycin: SE
A
- limited by their toxicity
-
ototoxicity (especially w/ diuretics → furosemide, mannitol)
- drug tends to concentrate around ear
-
nephrotoxicity (especially w/ ampho B, cyclosporine, etacrynic acid, vancomycin, NSAIDS)
- drug tends to concentrate around kidney
- skeletal muscle weakness: inhibit the pre junctional release of Ach and ↓ post synaptic sensitivity to the neurotransmitter (impacts patients with NM pathology i.e., MG) → profound blockade with NDNMB
17
Q
gentamycin: cautions/contraindications/drug interactions
A
- CAUTIONS
- hypersensitivity
- ↓ dose in RF
- vestibulocochlear impairment
- caution in pts w/ muscle weakness & MG
- ↑ nephrotoxic potential of other drugs such as loop diuretics, NSAID’s & other abx
- Crosses the placenta → could cause harm to fetus (ototoxicity, nephrotoxicity)
-
DRUG INTERACTION
- IV admin associated with potentiation of NDNMB (usually reversible with calcium and neostigmine)
18
Q
gentamycin: dose
A
- 60-120 mg IV
- toxic levels @ >9 mcg/ml – monitor levels
19
Q
clindamycin: class + use
A
- class
- Linomycin antibiotic
- use
- commonly used in female GU surgeries
- SSI prophylaxis with true anaphylactic PCN allergy
20
Q
clindamycin: MOA
A
- usually bacteriostatic
- blocks protein synthesis by binding to 50S ribosomal subunit
21
Q
clindamycin: PK
A
- Peak: 60 min
- E ½ t: 2.5 hours
- Metabolism: primarily hepatic
- Elimination: 10% excreted unchanged in urine
22
Q
clindamycin: SE
A
- Diarrhea (related or unrelated to pseudomembranous colitis due to C diff infection)
- Skin rash/hypersensitivity
- Prolonged pre and post junctional effects at NMJ in the* *absence of NDMR → not antagonized with anticholinesterases or calcium
- Blood dyscrasias (eosinophilia, leukopenia, thrombocytopenia)
23
Q
clindamycin: cautions/contraindications
A
- Severe liver disease – DOSE DECREASE
- Concurrent administration with NDMR can produce long lasting, profound neuromuscular blockade
- not antagonized with anticholinesterases or calcium
24
Q
clindamycin: dose
A
600 mg IV preop
25
vancomycin: class + use
* class
* broad-spectrum, glycopeptide antibiotic
* Gram + only
* narrow spectrum
* use
* activity against MRSA
* severe C diff infection
* good choice in severe PCN allergy patients
* severe staph infections
* streptococcal, enterococcal endocarditis
* cardiac/orthopedic procedures using prosthetic devices
* CSF and shunt related infections
26
vancomycin: MOA
* bactericidal – **“slowly” cidal**
* inhibits bacterial wall synthesis = cell lysis & death
* binds and inactivates cell wall precursors = “don’t have the building blocks”
27
vancomycin: PK
* _Peak_: 60 min
* _E ½ time_: 6 hours (up to 9 days with RF patients)
* _PB_: 50%
* Very poor absorption upon oral admin (PO only for intestinal infection)
* Slow CSF penetration unless there is meningeal inflammation
* Elimination: **90% unchanged in urine**
28
vancomycin: SE
* \*\*narrow therapeutic index\*\*
* Thrombophlebitis
* **Ototoxicity** @ conc \> 30 mcg/ml AND **nephrotoxicity** (increased risk if giving with aminoglycosides)
* Hypersensitivity (maculopapular skin rash)
* Severe hypotension and **“Red man syndrome”** (flushing due to histamine release) if given IV in less than 30 minutes
* diarrhea, GI upset
* thrombocytopenia (rare)
29
vancomycin: cautions/drug interactions
* **Cautions**
* hypersensitivity
* hearing loss
* renal failure (dose adjust)
* **_Drug Interactions_**
* *Other nephrotoxic drugs*: Toradol, NSAIDS, Ampho B, contrast dye, cyclosplorine
* _Synergistic_ action with aminoglycosides (vanc increases access of aminoglycosides to actual site of action → aminoglycosides then inhibit 30s ribosomal subunit) → HOWEVER, can also cause **additive toxicity**
30
vancomycin: dose
* 1 gram in 250 ml SLOWLY over 60 min
* 10 – 15 mg/kg SLOWLY over 60 minutes
31
metronidazole (flagyl): class + use
* class
* synthetic antibiotic
* use
* **\*\*recommended for pre-op prophylaxis for colorectal surgery\*\***
* endocarditis
* pseudomembranous colitis (C diff)
* abdominal and pelvic sepsis
* CNS infections
* anaerobic gram-negative bacilli & clostridium
32
metronidazole: MOA
* bactericidal
* broken down & activated by anaerobic organisms & form cytotoxic compounds that bind to bacteria & damage it
33
metronidazole: PK
* _E ½ t_: 8 hours
* _PB_: \<20%
* _Absorption_: well absorbed orally and widely distributed in tissue including CNS
* _Metabolism_: 30-60% in liver
* _Elimination_: **70%** excreted in the urine & **6-15%** fecal elimination
34
metronidazole: SE
* Dry mouth
* Metallic taste
* Nausea
* seizures
* Rare: neuropathy and pancreatitis
35
metronidazole: cautions/contraindications
* Avoid alcohol – disulfuram like reactions
* Seizure history
36
metronidazole: dose
**500 mg IV** over 10-20 min
37
ciprofloxacin: class + use
* CLASS
* broad-spectrum, fluoroquinolone antibiotic
* USE
* complicated GI/GU
* variety of systemic infections including resp. tract, TB, anthrax
38
ciprofloxacin: MOA
* bactericidal
* inhibits DNA gyrase and topoisomerase, which are critical bacterial enzymes used in DNA replication & cell division (stops growth and proliferation)
39
ciprofloxacin: PK
* _PB:_ 30%
* _Vd_: 2.5 L/kg
* _E ½ time_: 3 – 8 hours
* _Absorption_: GI absorption rapid and penetration to body fluids and tissues is excellent
* _Metabolism_: CYP450 metabolism in the liver
* _Elimination_**:**
* **30%** excreted in the feces
* **50%** excreted unchanged in the urine **(dose adjust RF)**
40
ciprofloxacin: SE
* Class warning for **QT prolongation**
* Rashes
* **Phototoxicity** (severe sunburn)
* Nausea
* CNS disturbances
* C diff superinfection, opportunistic candida
* **Tendinitis and Achilles tendon rupture** due to extracellular cartilage matrix weakening
* Highest risk: \>65, corticosteroid use, s/p transplant
* Avoid IV form \<18 years old → rare, but can cause disability because they’re still growing
41
ciprofloxacin: cautions/contraindications/drug interactions
* cautions
* **decrease dose in renal dysfunction**
* **caution with MG →** muscle weakness
* contraindications
* b/c of tendinitis and achilles tendon rupture:
* avoid IV form \< 18 yo
* age \> 65
* corticosteroid use
* s/p transplant
* **_Drug Interactions_**
* **__**CYP450 interactions (↑ levels of theophylline, warfarin and tinidazole)
42
ciprofloxacin: dose
**200-400 mg IV** over 60 min
