Anti-Infectives Flashcards
Goal of antiinfectives
reduce population of foreign organisms in host
Types of antiinfectives
- antibiotics (bacteria)
- antifungals
- antivirals
- antiprotozoals
how do antiinfectives work
- cell wall synthesis and permeability
- (we don’t have cell walls)
- interrupt protein synthesis
- interrupt DNA replication
- resource limitation
selective toxicity/
ability to affect certain proteins or enzyme systems that are used by infecting organsim but not by human cells
ability to target specific organisms
resistance
ability of pathogens over time to adapt to an antiinfective to produce cells that are no longer affected by a particular drug
ability of organism to evade effects of antiinfective
bactericidal
-substances that causes death of bacteria
-usually by interfering with cell membrane stability or with proteins/ enzymes that maintain cellular integrity of bacteria
bacteriostatic
- substance that prevents replication of bacteria
- usually by interfering with proteins/ enzyme systems necessary for reproduction of bacteria
superinfection
infections that occur when opportunistic pathogens that were kept in check by “normal” bacteria have opportunity to invade tissues and cause infections b/c normal flora bacteria have been destroyed by antibiotic therapy
treatment for initial infection led to 2nd infection
broad-spectrum antibiotics
effective against wide range of bacteria
narrow-spectrum antibiotics
effective only against very selective bacteria
combination therapy
- synergistic
- lower dose (fewer reactions)
- less resistance
- fewer superinfections
- one protects the other, - Unasyn (ampicillin and sulbactum), Augmentin (amoxicillin and clavulanic acid)
less neg effects on liver, kidneys
downsides to combination therapy
- increases risk of toxicity
- more side effects
- increased cost
- complicates compatibility issues via IV route
both hard on kidneys, both metabolized by liver
cultures
- optimally, ID organism first
- “match drug to bug”, 2-3 days though…
- often not feasible
- at least get cultures
- still not always feasible
- broad spectrum out the gate
get culture before you start antibiotics
types of cultures
gram stain - retains or loses stain after alcohol exposure
PCR - polymerase chain reaction - copies DNA to amount that are detectable
prophylaxis
- surgery
- valvular disease
- neutropenia
- recurrent infections
misuse of antibiotics
- treating viral infections
- treating “fever of unknown origin”
- wrong dose
- treating w/o knowing the bug
resistance
- reduction of drug at site of action
- alter the receptor site
- make their own weapons
- inactivate the drug
MRSA
- S. aureus
- colonizes our skin
- penicillin used widely starting 1940s
- resistance developed with penicillinase
- Methicillin - resistance developed as well - obsolete
- most common isolation indication
- requires stronger, more dangerous antibiotics to treat now - costs more
- increase LOS and morbities
proper antibiotic use
- complete full course
- allergies more likely when incomplete
- more likely to share or take later when incomplete
- resistant strains of bacteria
timely administration
- timeliness is important w/ antibiotic admin
- most require admin at specific frequencies
- some must reach certain concentration
- other more reliant on length of exposure
Vancomycin
- powerful antibiotic, used for C. diff and PCN resistnat S. aureus
- most common IV abx used in US hospitals
- risk of toxicity via IV route
- Kidneys (1 in 20) and ears
- reputation element may exist
- Trough level goal 5-20 mcg/mL
- admin’d over specific period of time
Red Man Syndrome
- peculiar to Vancomycin
- usually preceded by rapid administration
- flushing, rash, pruritis, tachycardia, hypotension
- infuse over at least 60 minutes
- supportive care antihistamines, steroids, fluids for hypotn
Clostridium difficile
- found in feces
- usually caused by antibiotic administration
- soap and water
- mild - metronidazole
- severe - vancomycin
- really severe - both
bad reactions
- range from mild to deadly
- N/V
- diarrhea
- itching, rash, anaphylaxis
Steven Johnson Syndrome
- autoimmune reaction to certain drugs, including some antibiotics
- skin and mucus membrane infammation and sloughing
- rare but serious
- starts with fever, burning pain in skin and eyes
- d/c with offending drug
- no specific treatment
- supportive care
tuberculosis
- replicates very slowly
- cough, low grade fever, night sweats, hemoptysis
- lengthens abx course
- multiple drugs
- compliance issues due to length of treatment and population
