Drugs: Antibiotics/Anesthetics Flashcards
true/false: Concentration dependent drugs are usually bactericidal
true
Name drugs that can be combined to broaden spectrum without causing antagonism
Aminoglycoside or fluroquinolones WITH B-lactams, metronidazole, or clindamycin
Which antibiotics work by affecting metabolic pathways? (2)
Trimathoprim or sulfonamide combos (folic acid synthesis)
Nitrofurans (acetyl CaA)
Which antibiotics interfere with cellular DNA/ division? (3)
FLamingoes RIde MEtros
Metronidazole, fluroquinolones, rifampin
Which antibiotics affect the cell wall? (4)
Bears play baseball viciously
B lactam (peptidoglycan interfere with transpeptidase) Vancomycin (elongation) polymixin, bacitracin (cell membrane)
Which antibiotics affect Protein synthesis? (5)
Mad CHeetahs CLimb African TrEes
macrolides 50 (erythromycin, azithromycin) chloramphenicol 50 clindamycin 50 aminoglycoside 30/50 tetracyclines 30
What is the mechanism of resistance and mode of action of beta-lactams?
inactivation by bacterial B lactamases (chromosomal mutations (gram +) or plasmid mediated resistance (gram +/-)
change in porin size
change in penicillin binding protein structure
what is a good antibiotic choice for a gram - aerobe and why?
Aminoglycosides are associated with least endotoxin release
fluoroquinoloneshave excellent distribution, wide therapeutic range
What are conditions that penicillins, cephalosporins and imipenum used for?
(B-lactamases)
urinary (1st gen), skin, respiratory
What drug is inactive in acidic environment and in low oxygen tension?
aminoglycoside (e.g. neomycin, gentamycin, amikacin, streptomycin)
Which drug has irreversible ototoxicity?
aminoglycosides
What can you do to prevent renal toxicity with aminoglycosides?
maintain hydration
once a day dosing
reduce conditions that affect renal prostaglandins (hypotension, shock, endotoxemia, renal or cardiac dz, NSAID, metabolic acidosis
What spectrum does the fluoroquinolones group have? e.g. enrofloxacin, marbo, cipro, orbi, difloxicin
broad gram -
aerobes
what are 2 side effects of using fluoroquinolones?
cartilage damage if < 9-18 mo
acute blindness in cats
Which drugs can be used for the prostate?
Desperate Times Call For CHocolate Milkshakes
doxycycline, Trimethoprim/sulfonamide combos
clindamycin, flouroquinolones, chloramphenicol, erythromycin=macrolide)
what are 2 side effects of TMS?
KCS
hypersentivity reaction
What antibiotics cross the BBB?
Timid DOgs Rarely MElt CHeese (For 3 Cents)
or Dirty Minds require full soap cleaning
Chloramphenicol (LIPID soluble and distributes many places), Metronidazole; TMS, doxycycline, rifampin,
flouroquinolones (sometimes)
3rd gen cephalosporin (if inflammation)
How does the acidic, hyperosmolar hypoxic environment of purulent exudate affect antibiotic efficacy?
A. inactivates aminoglycosides (O2)
B. impaired efficacy B-lactams (hyerosmol)
C. slower growth microorganisms = decreased efficacy of bactericidal drugs
D. impaired phagocytic activity of leukocytes
E. all of the above
E =ALL
inactivates aminoglycosides (O2/acid)
impaired efficacy B-lactams (hyerosmol)
slower growth microorganisms = decreased efficacy of bactericidal drugs
impaired phagocytic activity of leukocytes
Which drugs are affected by an acidic pH?
Erythromycin (macrolide) inhibited
B-lactams less activity (penicillins inactivated at (<6.0)
Aminoglycosides and fluoroquine less effective
What antibiotics are good for urine? ACIDIC? basic?
BaTq v…
acid urine: B-lactams and TMS basic urine (FQ, aminoglycosides, mac and linc)
BATQV have good concentration in urine (vancomycin)
True/False: As the generation increases, the efficacy against gram positive and anaerobes increases.
FALSE
higher generation = less effective against gram (+) and anaerobes
Antibiotics for the GB?
CRED
CLever Racroons MAke Drinks/Milk
Clindamycin, rifampin, macrolides(e/g erythromycin), doxycycline/minocycline
What antibiotics can enter WBC?
Frogs CLimb Moutain Ridges
fluroquinolone, Clindmamycin, erthrymcin/macrolide, rifampin,
Which benzodiazepine is better for a patient with liver disease? why?
Midazoam
Diazepam metabolites are active/potent and may cause excessive sedation
Which of the following statements is true?
A. Sighthounds take longer to recover when benzodiazepines are used.
B. Propofol has a low lipophilicity, and does not distribute well
C. Halothane induces more direct myocardial depression and sensitizes to catecholamine-induced arrhythmias
D. Glycopyrrolate has the most ocular effects, and should not be used with narrow-angle glaucoma
A. thiobarbituates –> sighthounds
B Propofol= highly lipid soluble, distributes
C TRUE
D scopolamin>atropine>glycopyrrolate ocular effects (no atropine for glaucoma)
True/False: Alfaxalone and propofol interact with the GABA receptor, increases chloride influx –> hyperpolarization = inhibition of arousal/awareness
true
Which inhalant produces compound A which can lead to renal injury in rats
sevofluorane
What is the order of inhalant MACs
Never Do Silly Dinosaurs Eat Icy Hot Medications
Never Do Silly Dinosaurs Eat Icy Hot Medications=
nitrous oxide> desfluorane> sevofluorane> diethylether> enflurane> isoflurane> halothane> methoxyflurane
What are the effects of anticholinergics on GI motility?
decrease LES function in monogastrics
(GI has M3 muscarinic receptors)
High dosese decreased motility for up to 30 min
What is the difference between atropine and glycopyrrolate?
glyco is 4x more potent, does NOT cross the BBB or the placenta, (poorly lipid soluble), takes longer to take effect, cardiac effects last longer
(heart has M2 muscarinic R)
What anticholinergics can prolong sedation due to effects at the M1 receptor (brain)?
scopalamine and atropine can cross the BBB
How does pimobendan work?
PDE II inhibition –> vasodilation
increased calcium sensitization with troponin C –> inotrope
Which vasopressor has a Beta affinity at an intermediate dose and an alpha effect at a high dose?
Dopamine
True/false: The LOWER the pKa, the GREATER the degree of ionization or proportion of local anesthetic in the ionized, charged, hydrophilic form at a physiologic pH and therefore a SLOWER onset of action
False: the HIGHER the pKa the greater ionization, and the slower the onset of action
What kind of neuromuscular blocking agent is succinylcholine?
Depolarizing
Name a short, moderate, and long acting local anesthesic?
short = procaine, benzocaine, chlorprocaine Moderate = lidocaine, mepivacaine (2hrs longer than lido) lon = bupivacaine, ropivacain
How does bupivacaine compare to lidocaine?
B = 4x as potent
Bup is highly lipophilic
True false: Are these in order of neuro/cytotoxicity? lidocaine< procaine< ropivacaine< mepivacaine< chlorprocaine< buprenorphine?
FALSE cytotoxicity =
pro
What nerves are you targetting when you approach with bupivacaine 0.5% and dexmedetomidine 0.5-2 ug/ml for a brachial plexus nerve block via a lateral approach, inserting cranial to acromion and medial to subscapularis
C6 = suprascapular C7 = Msculocutaneous C8* = radial and axillary want to see extension fo the elbow (contrction of triceps brachii) T1= median and ulnar
where do dissociative work?
NMDA (noncompetitive antagonists), opiod, monoaminergic and muscarinic receptors
interacts with voltage gated Ca channels
What are the main endogenous agonists for NMDA receptors?
glutamate, aspartate
glycine is a CO-agonist required to opent he channel efficiently
What is the first prostaglandin?
PGG2
which NSAIDs have the highest selectivity for COX-2?
Coxibs
carprofen and meloxicam somewhat preferential
What drugs target COX-1? and in what cell is this a dominant enzyme?
Aspirin, ketoprofen, etodolac
platelets
What prostaglandin is misoprostol an analogue of?
PGE1
increases bicarb production, mucus production, mucosal blood flow, decrease gastric acid secretion through decrease in intracellular cAMP
True/False: NSAIDs can directly insult gastric mucosa due to its lipophilic nature and diffusion, and indirect effects from prostaglandin inhibition
true
why is endogenous PGE2 important to the stomach? (4)
maintain gastric mucosal layer
quality of gastric mucus
mucosal blood flow
production of gastric acid
What two prostaglandins play an important role for renal blood flow and ion transport?
PGI2 (prostaacyclin) and PGE2
How do opioids affect the presynaptic membrane? the post-synaptic membrane?
pre: block release of glutamate, substance P and others
post: inhibit neuronal depolarization
Which of the following is NOT a dose-dependent effect of an opiate? A. GI motility B. Ventilation C. Sedation D. MAC reduction
A. GI motility is a receptor/species effect
Dose-dependent = vent, sed, MAC red, immune system
Species effects: thermoregulation, nausea, and GI
Route: urinary tract
True/False: fentanyl has a ceiling effect where higher doses produce longer duration, not higher effect.
FALSE: buprenorphine
Put the opiates in order of most to least lipophilic?
Big fat hippos mope
buprenorphine/fentanyl > hydromorphon> morphine (hydrophilic)
Lipophilic = absorbed well in IM, SC
morphin effects are delayed and pea 45 min after injection with prolonged effect (3-4 hrs)
how does gabapentin work?
pre-synap: voltage gated Ca channels –> dec. NT release
post-synpatic inhibition by hyperpolarizing inhibitory potentials (K or Cl) in dorsal horn
Which of the following is true?
a. Tramadol is an analogue of pregabalin
b. Tramadol and its metabolite are serotonig and norepi reuptake inhibitors
c. Tramadol binds strongly to the mu receptor
d. Horses and dogs are able to metabolize tramadol well
a. codeine
b. TRUE
c. weakly
What do neurokin-1 (NK1) receptor antagoinsts accomplish?
competitive binding –> antinausea, antidepressant, anxiolytic
What kind of drug is ondansetron?
5HT3 receptor antagonists (serotonin)
Endovaniolloids and capscasin (agonists) bind to what receptor?
TRPV1
