2 Antimicrobials Flashcards
bacteriocidal
directly lethal to bacteria, causing cell death
bacteriostatic
slows bacterial growth but does not cause cell death
selective toxicity
ability of a drug to injure a target cell without injuring other cells/organisms
time dependent killing
effect is dependent upon the concentration remaining above the minimum effective concentration (MEC) for a prolonged period of time
concentration dependent killing
effect is dependent upon reaching a concentration above the MEC
drug resistance
insensitivity/decreased sensitivity to a medication
- inherent, acquired (natural selection)
superinfection
secondary infection usually caused by depletion of natural flora, often fungal/yeast
opportunistic infection
infection by a microorganism that normally does not cause disease
- becomes pathogenic when the body’s immune system is impaired and unable to fight off infection
cell wall inhibitors x4
- pencillins
- cephalosporins
- carbapenems
- glycopeptides
bacteriocidal!
penicillin: pharmacokinetics
- widely distributed
- minimal metabolism
- excreted unchanged in urine and feces
penicillin: adverse effects
allergic reaction
- must have had prior exposure
- rash most common
- anaphylaxis
- CROSS SENSITIVITY TO CEPHALOSPORINS 10%
penicillin: important cross reactivity with…?
cephalosporins, 10%`
potential reactions types x3
- immediate (2-30 minutes)
- accelerated (1-72 hours)
- late (days or weeks)
anaphylaxis
- laryngeal edema
- bronchoconstriction
- severe hypotension
penicillin reactions: treatment
- epinephrine
- antihistamines (not for toxicities)
- cardiopulmonary support
penicillin desensitization
if only option, administer in ICU: monitor, give small amounts
extended and broad spectrum penicillin characteristics
- easily inactivated by beta-lactamase (deactivating enzymes within organism)
- combined with beta-lactamase inhibitors such as
- clavulanic acid
- sulbactam
cefotetan adverse effect
HUGE BLEEDING RISK
cephalosporins: generations
1,2,3,4
- increase in generation =
- increasing activity against G- and anaerobes
- decreased G+
- increased resistance to beta-lactamases
- increased cost
cephalosporin generation selection based on…
- antimicrobial spectrum
- route of administration
- side effect profile
- compliance
- access to care
cephalosporins: reaction with alcohol
especially cefotetan IV/IM
- disulfiram-like reaction (severe N/V)
carbapenem
- beta-lactam antibiotic
- very strong, frequently ised
- prototype: Primaxin (imipenem)
increasing generations of cephalosporins =
= increasing activity against G- and anaerobes
= increased resistance to beta-lactamases
= increased cost
= decreased G+
disulfiram
- discovered in the 1920s
- indication: chronic alcoholism
- produces acute sensitivity: blocks the processing of alcohol in the body by inhibiting acetaldehyde dehydrogenase = unpleasant reaction
otoxocity
ringing, deafness, buzzing
PERMANENT
Red Man Syndrome (general)
(exfoliative dermatitis)
- not allergic Type I Hypersensitivity
- due to destabilization of mast cells
- may require hospitalization at a burn unit
Red Man Syndrome (mild systemic symptoms)
- flushing/rash
- pruritis
- urticaria
- tachycardia
- hypotension
Red Man Syndrome (severe systemic symptoms)
- hypovolemia
- heart failure
- intestinal malabsorption
- hypoproteinemia
- hypothermia
antibiotic associated pseudomembranous colitis
- potentially fatal superinfection caused by C difficile
- profuse diarrhea, abdominal pain, fever, leukocytosis
- stools appear watery, mucoid, and bloody
pseudomembranous colitis treatment
PO vancomycin and/or metronidazole
- fluid replacement
- fecal transplantation (very high success rate)
reaction types
- immediate: 2 - 30 min
- delayed: 1 - 72 hours
- late: days or weeks
decision process for antibiotic selection
- recognize the clinical signs of infection
- investigate the possible source
- determine causative pathogen(s)
- select most appropriate class
- select most appropriate route
secondary considerations for antibiotic selection
- access to care
- patient sensitivity, compliance
- dosage
- dosage interval
- adverse effect profile
- drug interactions
Snape & McGonagall’s best practice
- get cultures ASAP
- make educated guess on RX
- start RX asap
- reassess when the culture is in
narrow-spectrum antibiotics
primarily effective against one type of organism
broad-spectrum antibiotics
are frequently used to treat infections when the offending microorganism has not been identified by C&S
parenteral
not oral/rectal (typically IV or injection)
enteral
related to GI tract
protein synthesis inhibitors (x5)
metronidazole macrolides tetracyclines aminoglycosides sulfonamides
bacteriostatic!!
cell wall inhibitors are…
bacteriocidal
protein synthesis inhibitors are…
bacteriostatic
Augmentin indications
respiratory infections
UTI
otitis media
sinusitis
beta-lactamase inhibitors x3
clavulanic acid
sulbactam
tazobactam
combined with a penicillinase-sensitive penicillin
