Antimicrobials Flashcards
Penicillin MOA and uses
bactericidal - messes with cell walls - peptidoglycan
broad spectrum - good for a lot of things - gram positive
how is PCN excreted
renal
plasma concentration decreases by half in first hour
anuria increases elimination half time by 10x
if you’re giving a probenecid, excretion is reduced
PCN big problem
beta-lactam ring = hypersensitivy in up to 10% of people
cross-sensitivity 3% of the time with cephalosporins because they share the ring
second generation penicillins?
amoxicillin and ampicillin - wider range of activity including gram neg
what is a good abx substitue for patients with documented IgE mediated anaphylactic reaction to B-lactum abx?
clindamycin or vanc
Cephalosporins MOA and use
cefazolin (ancef)
bactericidal, broad spectrum, but more widely used because low toxicity
higher generations = more reactive to gram neg
*also renal excretion
what are the macrolides, MOA, and use
Erythromycin, azithromycin
bacteriostatic or bactericidal - dose-dependent
block protein synthesis
broad spectrum - respiratory probs, STIs - chlamydia, gram positives
macrolides metabolism and excretion
CYP450 metabolism (can act like an inducer and increase serum concentraion of theophylline, warfarin, cyclosporine, methylprednisone, digoxin)
excreted in bile
good for renal patients**
macrolides side effects
INCREASED PERISTALSIS - gi upset
qt prolongation = torsades
thrombophlebitis so give in a good IV
Clindamycin (linomycins) - MOA, use
bacteriostatic
ACTIVE WITH ANAEROBES
commonly used for GU females
clindamycin probs
CAN CAUSE C DIFF
bad for liver disease
POTENTIATE BLOCKADE
Vancomycin MOA and use
bactericidal - impairs cell wall synthesis
gram positives!!!
Drug of choice for MRSA
used in combo with aminoglycosides for endocarditis
used for cardiac/ortho procedures with implants
CROSSES BBB (slowly unless meningeal inflammation)
used for bacteria resistant to other abx
vanc PK
renal excretion - half time is up to 6 hours and can be prolonged up to 9 days with renal failure patients (give them half the dose once a week)
poor PO absorption - give IV
Vanc dosing and adminstration
10-15mg/kg
give IV SLOW over 60 minutes
1 gram mixed in 250 ml
vanc side effects
rapid administration = profound hypotension
red man syndrome from histamine release
ototoxicity (with concentration >30mcg/ml) and nephrotoxicity (rare except when in combo with aminoglycosides)
give in big IV - phlebosclerotic
RETURN OF neuromuscular blockade
what can you administer with vanc to decrease histamine effects
give within 1 hr of induction:
1mgkg benadryl
4mg/kg cimetidine
Aminoglycosides what are they/uses. MOA
Bactericidal, inhibits protein synthesis good for TB and aerobic gram neg and pos
streptomycin - we don’t use
kanamycin - we don’t use
gentamicin - broad spectrum
amikacin - pseudomonas, infections caused by a gentamicin or tobramycin resistant gram neg bacilli
neomycin - skin, eye, mucous membrane (think neosporin), decrease bacteria in intestine before GI surgery
usually given in combo with a beta lactam for gram neg therapy
aminoglycoside excretion
renal - glom filtration
2-3 hour elimination half time increased 20-40x with renal failure
aminoglycoside SE
ototoxicity, nephrotoxicity, skeletal muscle weakness
POTENTIATES NDMR BLOCKADE - reversal may not be sustained with calcium or neostigmine
fluroquinolones (ciprofloxacin and moxifloxacin) use and MOA
Bactericidal, broad spectrum
good for gram neg and mycobac
complicated GI/GU infection
cipro - resp infections, TB, anthrax, bone/soft tissue infection
moxi - sinusitis, bronchitis, abd infection
fluroquinolones PK
rapid GI absorption
penetration to body fluid and tissue = excellent
renal excretion - required renal dosing
CYP450 inhibitor
fluroquinolone SE
TENDON RUPTURE
muscle weakness in MG
dizzy, insomnia, N/V
moxi = qt prolongation and SJS
Sulfonamides (sulfamethoxazole and trimethoprim) MOA/use
bacteriostatic - prevent bacteria from being able to synthesize folic acid
good for UTIs, IBS, Burns
sulfonamides PK and SE
liver acetylated and renal excretion - needs renal dosing
skin rash to anaphylaxis hepatotoxicity - thrombocytopenia, increase coagulant effects, hemolytic anemia allergic nephritis photosensitivity drug fever
Metronidazole - MOA/use
bactericidal
good fore anaerobic gram neg CNS - crosses BBB c-diff endocarditis abd sepsis preop prophylaxis for colorectal
metronidazole side effects
dry mouth
metallic taste
nausea
avoid alcohol
antimycobacterial first line agents
CSF penetration!! - used in combo therapy
Rifampin - bactericidal
Isoniazid - bacteriostatic (cidal with cell dividing)
Pyrazinamide - bateriostatic
Ethambutol - bacteriostatic
used in combo therapy for 2 months of 3-4 agents and then a minimum of 4 more months with 2 of them
name the statics
sulfonamides clindamycin macrolides (dose dependent) isonazid (non-rapid dividing) pyrazidimide ethambutol
abx that cross BBB
Vancomycin
Metronidazole
Antimycobacterials
Non-renal excretions abx
clinda = liver sulfonamides = liver and renal macrolides = excreted in bile
abx that effect NDMR
aminoglycosides = potentiate blockade clindamycin = potentiate blockade vancomycin = return of blockade
ABX that act like cyp450 inhibitors
macrolides
fluroquinolones
Antifungals - Amphotericin B
given for yeast/fungi
poor PO absorption
slow renal excretion - impairs renal function in 80% of patients on the drug (monitor plasma creatinine levels)
Side effects - fever, chills, hypotension with infusion, hypokalemia, allergic reactions, seizure, anemia, thrombocytopenia
not compatible with saline
how do antivirals work
there are some cell surface receptors unique to viruses and this gives a location for potential drug therapies
it is difficult to kill virus and not host
acyclovir
used to treat herpes
may cause renal damage
thrombophlebitis
patients may complain of headaches during IV infusion
interferons
bind to receptors on host cell membranes and induce the production of enzymes that inhibit viral replication - degrade viral mrna
treatment for hep b/c
side effects: flu like symptoms, autoimmune conditions, changes in CV, thyroid, and hepatic functions, alopecia, decreased mental concentration, depression, irritability
antiretroviral drugs
TRIPLE THERAPY chosen from 6 classes
- nucleoside/non-nucleotide reverse transcriptase inhibitors
- protease inhibitors
- fusion inhibitors
- CCR5 receptor antagonists
- integrase inhibitors
CRNAs should note that there are adverse effects with these drugs = liver toxicity, peripheral neuropathy, nephro-toxicity, neuromuscular weakness
inhibit cyp450
goals of antimicrobial therapy
- inhibit microorganisms at concentrations that are tolerated by the host
- seriously ill/immunocompromised select bacteriocidal
- narrow spectrum before broad spectrum or combo therapy to preserve normal flora
surgical site infections outcomes
SSIs develop in 2-5% or 30million surgical patients that cost 1 billion dollars/year
cause increased re-admissions, increased length of stay, and increased hospital cost
SSI definition
an infection related to an operative procedure that occurs at or near the surgical incision within 30 days of the procedure
purulent drainage from site
positive culture obtained from surgical site that was closed initially
surgeon’s diagnosis of infection
surgical site that requires reopening due to tenderness, swelling, redness, or heat
surgical risks for ssi
procedure type
skill of surgeon
Use of foreign material or implantable device or implantable device
degree of tissue trauma
patient risks for ssi
diabetes, smoking, obesity, malnutrition, steroid use, immunosuppressive therapy, intraoperative hypothermia, trauma, prosthetic heart valves
anesthesia impact on SSI
timely and appropriate use of abx
maintain normothermia
proper med admin
SCIP goals
give abx one hour prior to incision discontinue within 24 hours after surgery end time glucose control periop temp management VTE prophylaxis
dose of amoxicillin
2 gram po
dose of ampicillin
2 gram IV
clindamycin dose
600 mg IV
cefazolin dose
1 gm IV
