Antimicrobial Therapy Flashcards
(43 cards)
1
Q
Antimicrobial rules 4
A
- inhibit microorganisms at [ ]s that are tolerable by host–lowest possible dose
- Immunocompromised–BacterialCidal
- Narrow spectrum first or combination therapy to preserve normal flora
- Prophylactic given no more than 1 hr before incision
2
Q
Prophylactic abs given in OR…how often?
A
single dose or up to 48hrs
-no proof that this results in emergence of resistant organisms
3
Q
Abx selection
A
- *identify organism–essential
- efficacy depends on drug delivery to site (ex does it cross bbb)
- usually tx with single drug (but! is pt already on abx?)
- Route, Duration, Cost
- hardware
- Co-morbities (DM, immunosuppressed)
4
Q
Hypersensitivity
A
independent of dose
5
Q
Direct drug toxicity
A
dose related
6
Q
Parturient
A
pregers
- most abs cross placenta and enter maternal milk
- Teratogenecity–concern with any drug
7
Q
Elderly
A
renal impairment
decreased: plasma protein, gastric motility and acidity, liver function/mass
increase: body fat
8
Q
Penicillin and (gm what and their names)
A
Bactericidal gram + pneumo, meningo, streptococcal Renal excretion *most common for hypersensitivity--anaphylactic, rash/fever -Ampicillin, Amoxicillin
9
Q
Ampicillin
A
wider range of activity
Gm neg bacilli–H Flu and E coli
highest incidence of skin rash
10
Q
Amoxicillin
A
more efficiently absorbed from the GI tract than ampicillin
PO–ear infection
11
Q
Cephalosporin
A
Batericidal Broad spectrum Renal excretion Adverse reaction: allergic--rash --anaphylactic reaction 0.02% cross sensitivity btwn cephalosporins and PCN but only 8%
12
Q
Cephalosporin classification
A
increased activity against bacteria as generation increase
1st: cefazolin
2nd: cefoxitin
3rd: cefotaxime
13
Q
Aminoglycosides
A
Bactericidal gram neg Extensive renal excretion --2-3hr elimnation half time Increased 20-40 fold in RENAL FAILURE adverse reactions: -ototoxicity -nephrotoxicity -skeletal muscle weakness -prolongs neuromuscular blockade
14
Q
Aminoglycosides Ototoxicity
A
Vestibular/auditory dysfunction
- destruction of cochlear sensory hairs
- does dependent– usually occurs with chronic therapy
15
Q
Aminoglycosides Nephrotoxicity
A
accumulate in renal cortex-tubular necrosis
- inability to concentrate urine, proteinuria and RBC casts
- Reversible–when drug stopped
- Most nephrotoxic: NEOMYCIN– monitor BUN and creatin
16
Q
Aminoglycosides Skeletal muscle weakness
A
- can inhibit PRE junctional release of ACH
- decreased POST synaptic sensitivity to neurotransmitter
- Myasthenia graves–uniquely sensitive to weakness
- *single dose in healthy pt not a problem
- can give Ca to help
17
Q
Aminoglycosides Potentiation of neuromuscular (NM) blockade
A
- high plasma [ ] when given IV
- systemic absorption from lg volumes of irrigation
- Reappearance of NM blockage in PACU
- NM blocking properties of lidocaine are enhanced
- *neostigmine or Ca induced antagonism may be imcomplete or transient— monitor and use nerve stimulator
18
Q
Aminoglycosides types 4
A
- Streptomycin & Kanamycin
- Limited uses
- Frequent occurrence of vestibular damage
- Gentamicin
- Broader spectrum
- Toxic level – (> 9mcg/ml)
- Amikacin
- Derivative of kanamycin
- Neomycin
- Adjunct therapy to hepatic coma
19
Q
Tetracycline
A
bacteriostatic Tx-acne Excreted in urine and bile Side effects: -permanent discoloration of the teeth--not given to parturients or children -phototoxicity
20
Q
Tetracycline types
A
tetracycline-PO only
Doxycyline- IV or PO, long acting preparation
21
Q
Macrolides
A
Erythromycin bacteriostatic or -cidal -Narrow spectrum-- mostly gram + metabolized by C-450-excreted mostly in bile -no altered dose in renal disease
22
Q
Erythromycin adverse reactions
A
GI intolerance, sever N/V with IV infusion*most common
-Gastric emptying
QT effects-prolongs cardiac repolarization and report of torsades
-Thrombophlebitis– with prolonged IV use
23
Q
Clindamycin
A
class: lincosamides
bacteriostatic
-similar to erythromycin, more active on anaerobes
Tx-serious infection in GI tract and female genital tract
-decrease with sever liver disease
24
Q
Clindamycin side effects
A
- Pseudomembranous colitis– severe diarrhea
- Pre and post junctional effects at the neuromuscular junction
- -Not antagonized with anticholinesterases or calcium
- -Large doses can produce long lasting, profound neuromuscular blockade
25
Vancomycin
```
Glycopeptide derivative
-bactericidal
for Gram pos: -severe staph infection
-streptococcal, enterococcal endocarditis
-methicillin resistant staph aureus
-PCN/Cephalosporin allergy
Renal excretion: elimination 1/2 life is 6hrs **can be up to 9 days with renal failure puts
**monitor renal--Renal dosing
```
26
Vanco tx
Cardiac procedures
Ortho with prosthetic devices
CSF and shunt related infections
27
Vanco dosing and adverse effects
```
10-15mg/kg over 60 min---1gm in 250ml
Adverse effects:
-rapid infusion--profound HypOtension
-red man--facial and truncal erythema form histamine release
-Ototoxicity/Nephrotoxicity
-return of neuromuscular blockade?
```
28
Sulfonamides
```
bacteriostatic
*inhibit microbial synthesis of folic acid
Tx- UTIs
hepatic metabolism with renal excretion
Adverse effects:
-skin rash to anaphylaxis
**increase effect of PO anticoagulants
```
29
Polymycxin B and Colistimethate
bactericidal
gram neg
Tx- UTI, infections of skin, mucous membranes, eyes and ears
Eliminated by kidneys--accumulate in renal failure
30
Polymycxin B and Colistimethate Side Effects
*most potent of all antimicrobials in their action at NM junction
*predominantly PRE junctional
-can produce skeletal muscle weakness resembling nondepolarizing NM blockade
-Marked potentiation of nondepolarizing neuromuscular blocking drugs
-Neostigmine or calcium do not reliably antagonize this drug induced effect at the NM junction
HIGHLY nephrotoxic
31
Metronidazole
Bactericidal
- Anaerobic Gm (-) bacilli
- Tx:
- CNS infections
- Abdominal and pelvic sepsis
- Pseudomembranous colitis
32
Fluoroquinolone
```
BacteriCidal
broad spectrum
Enteric gm neg
-elimination 1.2 time 3-8hrs
-can inhibit P450 enzymes
-mostly renal excretion
--decrease dose in renal dysfunction
Tx-complicated GI and GU
**Ciprofloxacin-tx of systemic infection-bone, soft tissue and resp tract
```
33
Fluoroquinolone side effects
minimal
| mild GI disturbances
34
Rifampin
```
for TB
bactericidal for mycovateria
inhibits most Gm+ and many gm-
-fat soluble--penetration of tissue including CNS
-oral or IV
-excreted in blie and urine
```
35
Rifampin side effects
usually infrequent
- High doses- thrombocytopenia, anemia, hepatitis, fatigue, numbness, skeletal muscle weakness
- potent inducer of C P450 system- accelerate metabolism of opioids, NM blocking agents, warfarin
36
Amphotericin B
antifungal
tx-yeast and fungi
Slow renal excretion
--renal function is impaired in 80% of pt treated with this drug
--most recover, some result in permanent decrease in glomerular filtration rate
--monitor plama creatinine levels
37
Amphotericin B side effects
- fever, chills, dyspnes, hypotension-can occur during infusion
- impaired hepatic function
- allergic reaction
- seizure
- anemia
- thrombocytopenia
38
Viruses
-intracellur parasites, can't reproduce outside of host cell
-composed of a nucleic acid core surrounded by a protein containing outer coat
-genome either DNA or RNA, never both-classified on this basis-use many biochemical mechanisms of host cell
*development of antiviral is difficult
Vaccines are the alternative
-hep A and B
-HPV
-herpes zoster
39
Antivirals (6)
* *Acyclovir and Valacyclovir
- limited to Tx of herpes viruses
- excreted by kidney
* *Vidarabine
- cytomegalic inclusion disease
- herpes simplex encephalitis
- mutagenic and carcinogenic
* Famciclovir
- acute herpes zoster
* Ganciclovir
- Cytomegalovirus disease
- hematologic toxicity
* Amantadine
- influenza A virus/ parkinsons
- renal excretion
40
interferons
- glycoproteins produced in response to viral infections
- bind to receptors on host cell membranes and induce the production of enzymes that inhibit viral replication
- -degradation of viral mRNA
- enhances tumoricidal activities of macrophages
- Chronic hep B
- hepatitis C
- Nasal sprays
41
interferons side effects
```
flu like symptoms
hematologic toxicity
depression, irritability
decreased mental concentration
development of autoummune conitions
rashes, slopecia
changes in CV, thyroid, hepatic functions
```
42
Antivirals for AIDS
NUcleoside reverse transcriptase inhibitors (NRTI)
--imposter
Nonnucleoside revers transcriptase inhibitors (NNRTI)
--inhibit function of enzyme used by virus
Protease inhibitors
--Bind to HIV protease
*combination therapy
43
Antivirals for AIDS side effects
Many and varied:
- Pancreatitis, hepatotoxicity , lactic acidosis, fat redistribution, increases in serum cholesterol and triglycerides, hypersensitivity
* *Proteaseinhibitor
- Most all inhibit CP450 system
- Ritonavir most potent inhibitor
- Large plasma increases of many drugs including analgesics, lidocaine, antimicrobials, anticonvulsants, anticoagulants, antiemetics, calcium channel
