antibiotics Flashcards
what is pharmacokinetics?
what body does to drug (L, A,D, M,E)
What is pharmacodynamics?
what drug does to body
what is MIC ( minimum inhibitory concentration) & MBC (minimum drug- concentration)?
minimum inhibitory concentration :
- minimum drug concentration INHIBITING MICROBIAL GROWTH in virtro
minimum bacteriocidal conc
- Minimum drug concentration that KILLS MICROBES IN VITRO
MBC is 2-4 fold of mIC
concentration to MIC (Cmax : MIC)
every dose’s concentration spikes and goes down.
area under curve to MIC
drug effectiveness is affected by AMOUNT OF TIME SPENT IN MICR RANGE …. NOT DOSE
bioavailibility
drug that reaches circulation (%)
clearence
vol of fluid removed per unit of time
volume of distribution
high protein binding drugs have LOWER VD . The more lipophilic, the HIGHER THE VD
steady state
imp for MIC to AUC ratio & fraction of time
therapeutic index
range between minimum effective conc to mimumum toxic conc
factors effecting host
age (extremeties)
renal/liver function
co-morbidities
polypharmacy
allergy
conditions (Myasthesia gravis, G6PD)
drugs to avoid in myasthesia gravis
drugs impair Neuromuscular junction transmission
result: increase of weakness
Aminoglycosides
fluroquininolones
tetracyclines
clindamycin
sulfonamides
macrolides
ampicillin
antimicrobial drugs have adverse reactions, name them
- allergic reactions
- toxic effects - at high
dose - bioflor suppression - allowing growth ex: clostridium difficile
staining techniques
provide contrast by using dyes
smear –> air dye –> heat fix
types of dye used in staining techniques
- basic - cationic chromaphore
- acidic - anionic chromophore - negative staining
3 types of staining techniques
- simple
- differencial
- special
acid fast stain - test for microbacterial cell walls
cells retaining basic stain in acid-alcohol
What are the characteristic factors of an antibiotic
selective toxicity -
- target bacteria while causing NO OR MINIMAL HARM to patient
Therapeutic index -
- ratio between TOXIC and therapeutic
antimicrobial action -
Bacteriostatic: prevents further bacterial growth
- bacteriocidal - kills bacteria
activity spectrum
- broad - target gram +ve & -ve
- narrow - gram -ve or gram +ve ONLY
ADME -
- BBB - blood brain barrier antibiotics (cephalosporins, doxycycline)
- unstable in acid
- half life duration
explain selective toxicity in antibiotics
they target bacteria
BUT
cause NO or minimal harm to patient
types of antibiotic
broad - gram +ve/-ve
narrow - only gram +ve OR -ve
bacteriocidal - kills
bacreriostatic - suppress growth
gram postitive
- thick peptidoglycan
- porous (lets in easy)
- CRYSTAL VIOLET gram stain absorbed into peptidoglycan
gram negative
- THIN peptidoglycan
- have 2nd outer membrane
- outer layer not allow crystal violet to reach peptiodglycan - Pink counterstain
Gram +ve vs Gram -ve
-ve –> outer membrane makes it harder for antibiotics to cross
+ve –> greater access to antibiotics –> more easy penetration + interaction with peptidoglycan
Bactericidal antibiotics
kill the bacteria
what do antibiotics target to kill bacteria?
- cell wall synthesis (structure & arrangment of peptidoglycan)
- protein synthesis
- nucleic acid synthesis
- metabolic reactions
- membrane function
what is peptidoglycan
backbone of carbohydrate units with sets of amino acid residues attached
