Lecture 4 9/20/23 Flashcards
What is pharmacodynamics?
effect of the drug on the body, including mechanisms of action and efficacy
What is pharmokinetics?
fate of the drug in the body
What is the post-antibiotic effect?
the suppression of bacterial growth that persists after treatment
How do time-dependent vs concentration-dependent antibiotics differ?
-time-dependent antibiotics have a short post-antibiotic effect and must by given more frequently regardless of dose
-concentration-dependent antibiotics have a longer post-antibiotic effect, and higher concentrations can be effective for longer periods of time
Which antibiotics are classified as beta lactams?
-penicillin
-ampicillin
-cephalosporins
-sublactams
-carbapenems
-monobactams
What is the mechanism of action for beta lactams?
inhibition of cell wall synthesis
What is the spectrum of activity for beta lactams?
different spectrum for each antibiotic
What is the type of antibacterial activity for beta lactams?
bactericidal
What are the potential adverse effects of beta lactams?
-penicillin allergy/anaphylaxis
-time-dependent killing
What antibiotics are classified as tetracyclines?
-oxytetracycline
-doxycycline
-minocycline
What is the mechanism of action for tetracyclines?
inhibition of protein synthesis
What is the spectrum of tetracyclines?
broad spectrum
What is the type of antibacterial activity for tetracyclines?
bacteriostatic
What are the potential adverse effects of tetracyclines?
-irritant
-cardiovascular effects
-tooth discolaration
-intestinal flora alteration
-nephrotoxicity
What other critical information exists for tetracyclines?
-time dependent
-chelating agents
-cross placental barrier
-secreted in milk
-anti-inflammatory
-neuro-protective
-immunomodulant
What antibiotics are classified as aminoglycosides?
-gentamicin
-amikacin
-tobramycin
What is the mechanism of action for aminoglycosides?
inhibition of protein synthesis
What is the spectrum of activity for aminoglycosides?
broad spectrum
What is the type of antibacterial activity for aminoglycosides?
bactericidal
What are the potential adverse effects of aminoglycosides?
-nephrotoxicity
-ototoxicity
-cranial nerve VII toxicity
-vestibular/cochlear damage
What other critical information exists for aminoglycosides?
-concentration dependent
-oxygen dependent
-prolonged post-antibiotic effect
-needs parenteral admin.
-does not penetrate blood brain barrier
-synergism w/ beta lactams, but physically incompatible
What antibiotics are classified as fluoroquinolones?
-enrofloxacin
-ciprofloxacin
What is the mechanism of action for fluoroquinolones?
inhibition of DNA gyrase
What is the spectrum of activity for fluoroquinolones?
broad spectrum
What is the type of antibacterial activity for fluoroquinolones?
bactericidal
What are the potential adverse effects of fluoroquinolones?
-arthropathy
-ocular toxicity
What other critical information exists for fluoroquinolones?
-synthetic
-concentration dependent
-high intracellular conc. in phagocytes
-prolonged post-antibiotic effect
-rapid resistance development
What antibiotics are classified as macrolides?
-erythromycin
-azithromycin
-clarithromycin
What is the mechanism of action for macrolides?
inhibition of protein synthesis
What is the spectrum of activity for macrolides?
broad spectrum
What is the type of antibacterial activity for macrolides?
bacteriostatic
What are the potential adverse effects of macrolides?
GI effects
What other critical information exists for macrolides?
-intracellular accumulation in phagocytes
-effective against intracellular bact.
-immunomodulary effect
What antibiotics are classified as sulfa drugs?
-sulphonamide
-sulfamethoxazole
-sulfadiazine
What is the mechanism of action for sulfa drugs?
inhibition of folic acid synthesis, preventing the nucleic acid synthesis pathway
What is the spectrum of activity for sulfa drugs?
broad spectrum
What is the type of antibacterial activity for sulfa drugs?
bacteriostatic
What are the potential adverse effects of sulfa drugs?
-allergic reactions
-keratoconjunctivitis
What other critical information exists for sulfa drugs?
synergistic with diaminopyrimidines
What are the reasons for bacterial culture and antimicrobial susceptibility testing?
-confirm presence of bact. infection
-identify responsible pathogen
-choose most effective antibiotic
-improve recovery chances/speed
-lower complications
-reduce resistance
-reduce expenses
What are important points to consider regarding resistance?
-bact. may be intrinsically resistant
-knowledge of resistance can help avoid inappropriate/ineffective therapies
What is the antimicrobial susceptibility test?
test to determine whether bacteria are susceptible to a particular antimicrobial agent
What are the two types of AST?
-broth/agar dilution
-disk diffusion
How are bacteria determined to be susceptible via the disk diffusion test?
greater zone of inhibition diameter indicates greater susceptibility
How are bacteria determined to be susceptible via the broth dilution test?
the lower the minimum inhibitory concentration, the greater the susceptibility
What is the minimum inhibitory conc.?
the minimum amount of drug required to inhibit bact. growth
What is the E-Test-Gradient diffusion test?
test that uses both diffusion and dilution to measure an exact MIC
Why can it be beneficial to use antimicrobial combinations?
-obtain antimicrobial synergism
-treat polymicrobial infections
-decrease resistance
-reduce drug toxicity
What is four-quadrant therapy?
-method for treating microbial infection when pathogen is unknown and consequences of treatment failure are severe
-includes antibiotics to treat gram + aerobes, gram + anaerobes, gram - aerobes, and gram - anaerobes
-effective against all likely bacteria
-NOT just using a broad spectrum
