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101 Cards in this Set
- Front
- Back
- 3rd side (hint)
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full agonist opioids
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codeine
morphine oxymorphone |
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mixed agonist opioids
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butorphanol
burprenorphine tramadol |
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Histamine
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found in mast cells
receptors: H1 in vasculature and bronchi H2 receptors in gi tract Effects: vasodilation, bronchoconstriction, increased secretions, increased capillary permeability |
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Antihistamines
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prevention of histamine release
stabilize membranes of mast cells |
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ranitidine
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antihistamine
competitive antagonist at H-2 receptor |
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competitive antagonism at H-1 receptor
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H1 blockade - relaxes bronchial smooth muscle, decreases capillary permeability, decrease respiratory secretions, decrease itch
CNS depression : sedatives/tranquilizers, pre-anesth. anticholinergic/antiemetic action and uses - decrease vomiting, vertigo, secretions SE: dry mouth |
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phenothiazine
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acepromazine
- anti H1 -sedation -anticholinergic/antiemetic |
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bronchodilators
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direct sympathomimetics (epinephrine)
methylxanthines (theophylline) |
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other treatments for manifestations of inflammation
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gold
immunosuppressants:(glucocorticoids/cytotoxic agents) mucopolysaccharides topical analgesics |
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火麻仁
huŏ má rén |
Linum (Semen Cannabis Sativae)
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Downward Draining Herbs
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general side effects of antibacterial agents
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GI manifestations
allergies irritation at injection site superinfections (decreased vit K) |
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factors to consider when using chemotherapeutic agents
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diagnosis (primary importance)
drug choice (susceptibility, MIC) host (patient) factors client factors |
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bacterial resistance mechanisms
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decreased drug penetration
decreased susceptibility of targer increased destruction of drug |
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targets of anti-infectives
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cell wall/membrane (-cidal = kill)
decreased protein synthesis (- static = keep from growing/reproducing) nucleic acids (DNA or DNA enzymes -cidal) cell metabolism (-static) |
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choices of drug
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diagnosis
susceptibility target patient's immune system |
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Types of Drug interactions
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-acid-base (physical incompatibility)
- -cidal/-static (pharmacological antagonism) -additive or synergistic/potentiating effects due to pharmocodynamics or pharmocokinetics (interactions: -cidal/-static , among sulfadrugs, with NM blockers) |
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host (patient) factors
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-immune system must be able to help fight disease
- preexisting disease may interfere with host factors |
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client factors
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cost
compliance with instructions information clients receive on DVM-prescribed drugs and other meds transmission of resistant microorganisms to man residues can occur (some harmful) |
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misuse of antiinfectives
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treating the unknown or untreatable
over-treating (broad spectrum rather than narrow) undertreating (consider MIC and duration) mistreating (consider pharm prep, route, solubility, stability) |
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BIG PROBLEMS WITH ANTIMICROBIALS
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Residues and Resistance
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classes of bacteriocidal drugs
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penicillins, cephalosporins, other beta-lactams, aminoglycosides (high dose), polymyxins, fluoroquinolones, sulfa with trimethoprim, nitrofurans
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classes of bacteriostatic drugs
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sulfas, tetracyclines, chloramphenicol, aminoglycosides (low dose), spectinomycin, macrolides, lincosamides
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sulfonamides
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antibacterial and antiprotozoal
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sulfonamides: absorption/distribution
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weak acids (have good absorption PO)
high pKa (range from 4-11) water insoluble may use loading doses to reach steady state faster some rel. high protein binding |
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sulfonamides: metabolism
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occurs primarily in the liver
patient must be well hydrated so it doesn't precipitate in the kidneys (acetylation decreases aqueous sol.) |
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sulfonamides: excretion (elimination; clearance)
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urinary concentration higher than blood
weak acid so tubular secretion also secreted in feces and milk (residues) |
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sulfonamides: mechanism of action
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-static drugs
PABA substitutes in folic acid synth. broad spectrum (G+, G-, anaerobes, aerobes, protozoa---- as long as microbe needs PABA) |
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Trimethoprim
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inhibits folate reductase, creating a -cidal combination with s-drugs
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sulfonamides: spectrum/indications/uses
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systemic bacterial infections (respiratory, urinary tract)
mastitis coccidiostatic action --- need to give sufficient amt. long enough |
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sulfonamides: adverse reactions
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high margin of safety
-but poor water solubility and high conc. in kidney can cause precipitates immune-mediated rxns affecting skin, blood, liver, or NS long term use can decrease lacrimal secretions |
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sulfonamides: drug interactions
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advantageous: s-drug w/ s-drug; s-drug + trimethoprim (-cidal)
detrimental: s-drug w/ PABA; s-drug w/ other protein bound drugs; bacteriostatic s-drug w/ bacteriocidal drugs |
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sulfonamides: residues
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-problem
used in food animals and as feed additives ---withdrawl ~15 days |
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quinolones (fluoroquinolones): chemistry
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weak acids with F group
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enrofloxacin
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fluoroquinolone
PO and injectable for dogs and cattle w/ respiratory disease; topical for canine ears DNA gyrase inhibitor |
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quinolones: mechanism of action
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DNA gyrase inhibition
inhibits DNA replication (-cidal) rel. broad spectrum (G- > G+ aerobes) not anaerobes RESERVE ANTIBACTERIAL (no extralabel use in FA) |
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quinolones: absorption
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absorption: usu given slow and variable
bioavail: ~60% (decreased by antacids) |
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quinolones: distribution
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not significantly protein bound
distibutes and concentrates in muscle (residues), bone, milk, placenta |
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quinolones: clearance
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multi-compartment model
clears slower in young liver metabolism (50% eventually excreted as glucuronides via kidney--- also non-urinary excretion: milk, feces) newer fluoroquinolones clear slower |
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quinolones: adverse effects
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significant: gi disturbances, damage to developing cartilage
other: histamine release w/ high dose, urinary crystals if pt. dehydrated- chelates cations, photosensitization -----decr. GABA may cause seizures if given fast IV RESISTANCE |
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quinolones: drug interactions
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associated with weak acids and renal toxicants
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Metranidazole: chemistry
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contains -NO2 group that is reduced by microbes
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Metranidazole: uses
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primarily for anaerobes (esp G-)
use for protozoa (giardiasis) |
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Metranidazole: kinetics and dynamics
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weak base w/ pKa of 2.5
readily absorbed PO and generally distributed Metab by reduction to create active drug urinary excretion of metabolites |
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Metranidazole: Adverse effects
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relatively rare and relatively minor (gi)
very high dose can cause seizures |
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Nitrofurans (synthetic antibacterial)
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chem: weak acids
spectrum: broad (G+, G-), damage dna so -cidal considerations: yellow staining, irritation, immune-med. rxn topical use not perm. in FA |
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povidone iodine
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=halogenated antiseptic
broad spectrum- causes nonspecific protein precipitation (-cidal) can use as a wound treatment |
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weak acid antibiotic classes
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sulfonamides
fluoroquinolone penicillin cephalosporin fenicols |
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weak base antibiotic classes
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metronidazole
polypeptides aminoglycosides tetracyclines lincosamides |
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B-lactams: distribution
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polar- so don't go inside host cells (therefore little metabolism)
not distrib. to the CNS expect low Vd b/c stays in body H20 |
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what is the mechanism of action of beta-lactam antibiotics
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on the cell wall (-cidal)
inhibit the transpeptidase that links the peptides of the cell wall -only effective on growing bact. cells -in gen. have large margin of safety (allows for pulse dosing) |
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beta-lactam: spectrum
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depends on the drug - may be narrow or broad
aerobes/anaerobes resistance and cross-resistance occur |
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beta-lactams: mechanisms of resistance
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1. failure to penetrate (can occur w/ g- cell wall)
2. insensitive to target 3. increased degradation |
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types of beta-lactams
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penicillins
cephalosporins new betalactams (reserve) |
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3 subtypes of penicillin
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'original'
extended spectrum penicillinase resistant |
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penicillin G (natural): advantages
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large margin of safety
narrow spectrum (G+), aerobes/anaerobe approved use in FA duration can be mod. pharmaceut. |
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penicillin G: disadvantages
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unstable
resistance (OTC availability) narrow spectrum (G+) short duration unless modified allergies unavailability of inexpensive IV prep |
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pharmaceutical modiications that alter kinetics to increase duration of action
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vehicle - oil
soluble and insoluble salts combo with probenecid phenoxymethyl deriv. for PO admin. no opthalmic use (pot. for sys. absorb) |
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extended spectrum penicillins
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aminopenicillins (ex. ampicillin):
amine group on side chain antipseudomonal penicillins: double carboxylic acids |
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advantages of aminopenicillins
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-broader spectrum (g+ and some G-)
-PO possible -dosage in mg instead of units absorp. can be mod. with salt avail. of soluble salt |
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disadvantages of aminopenicillins
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unstable solutions
lack of availability in sizes useful for LA resistance!!!! cross-allergies |
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bulky penicillins
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penicillinase resistant
work by keeping b-lactamases from b-lactam ring have a big group on side chain disadv: narrow spectrum; evolving transmissible resistance; cost |
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b-lactamase inhibitors
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clavulonic acid - looks like penicillin b/c has a square ring so binds the b-lactamase and saves the penicillin
-treat infect. caused by resist. bact. costly |
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cephalosporins
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weak acid
-cidal (action on transpeptidase) short half-life not intracellular; not in CNS; not metab. much; tubular secretion primary use: systemic effects |
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1st generation Cephalosporin
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ex. cefadroxil
G+ > G- PO/parenteral/topical $ prophylactic most resistance |
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2nd generation cephalosporin
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broadest spectrum
all parenteral $$$ (costly) - limits vet use |
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3rd generation cephalosporin
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G+ < G-
parenteral (some PO) $$ (has most costly cephalosporins) Widely used in LA med. |
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cephalosporins: resistance due to...
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decreased penetration
B-lactamase (cephalosporinase) and changes in binding proteins B-lacamase inhibs. used w/ penicillins are not useful with cephalosporins |
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cephalosporins: kinetics
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weak acids: PO F >79%
all are absorbed parenterally not intracellular; not to CSF if normal; some are rel. highly protein bound concentrations in urine > in blood little metab.; tubular secretion |
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cephalosporins: adverse effects
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like penicillins (allergies, cross-all.)
high margin of safety injections are irritating nephrotoxic in dehydrated animals or if taken w/ other nephrotoxic drugs take into account drug interactions |
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Polypeptide antibiotics
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-cidal
cell wall or cell membrane large MW - too large to get into cells not absorbed topically or PO RESERVE ANTIBIOTICS -for systemic disease |
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polypeptide antibiotics: side effects
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none topically
systemic admin. can result in nephrotoxicity neurotoxicity can occur (NM blocker) |
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2 mechanisms of aminoglycosides that will damage bacterial cells
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1. have an affinity for bact. cell membranes, interfering with membrane function (leads to leaky membranes, -cidal)
inhib. protein synthesis through action on 30s ribosome (-static) |
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aminoglycosides
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not effective against anaerobes
admin. parenterally or locally very low margin of safety (2-5) - cidal conc. near toxic levels nephrotoxicity neurotoxicity |
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adverse effects and problems with aminoglycosides
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low margin of safety
nephrotoxicity (accum. in kidney) neurotoxicity (8th cranial nerve) residues (in H20 contain. structures) extra label use in FA not recommend. |
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Tetracyclines: chemistry
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ex. tetracycline, doxycycline
highly lipophilic, very weak base, may come as HCL salt |
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Tetracyclines: kinetics
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absorption occurs after all routes of administration (be careful when IV)
bind to plasma proteins and like lipid-containing tissues (ex.milk) Vd is large clearance - kidney, feces, milk |
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Tetracyclines: mech of action
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effect on 30s ribosome prevents tRNA access to mRNA so no initiation of protein synthesis; -static action
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tetracyclines: spectrum, uses
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broad spectrum (G+ and G- aerobes and anaerobes)
also against - rickettsia, chlamydophila, and mycoplasma treat a variety of systemic infections |
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tetracyclines: resistance
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-widespread
occurs primarily b/c bacterial cells mutate to alter proteins that permit drug uptake |
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Tetracyclines: adverse effects and problems
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contraindications: b/c Ca and Fe chelators (in pregnancy and in foals)
superinfections -likely b/c broad spec. organ toxicities (outdated drugs); phlebitis (IV use); alter bones/teeth; diarrhea; photosens. residues; interactions |
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tetracycliens: drug interactions
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-static drugs should not be used with -cidal drugs
inhibit protein synthesis, therefore inhibit microsomal enzymes |
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Fenicols:chemistry/kinetics
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amphoteric molecule
weak acid admin. po, parenterally, or topically generally distrib. throughout body (even CSF) w/ little plasma protein binding |
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Fenicols:dynamics
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action on 50s ribosome prevents protein elongation (-static)
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Fenicols: side effects
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General SE's
capability to inhibit protein synth. can result in reversible hematopoietic damage aplastic anemia in humans |
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Fenicols: drug interactions
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-drugs that act on the 50s ribosome competitively inhibit each other
-action of drugs metabolized by hepatic microsomal enzymes would be prolonged |
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drugs with action on 50s ribosome
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fenicols
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Fenicols:chemistry/kinetics
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amphoteric molecule
weak acid admin. po, parenterally, or topically generally distrib. throughout body (even CSF) w/ little plasma protein binding |
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Fenicols:dynamics
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action on 50s ribosome prevents protein elongation (-static)
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Fenicols: side effects
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General SE's
capability to inhibit protein synth. can result in reversible hematopoietic damage aplastic anemia in humans |
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Fenicols: drug interactions
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-drugs that act on the 50s ribosome competitively inhibit each other
-action of drugs metabolized by hepatic microsomal enzymes would be prolonged |
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drugs with action on 50s ribosome
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fenicols
macrolides lincosamides |
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Macrolides
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narrow spectrum (mostly G+)
act on 50s ribosome (-static) lipophilic molecule Rifampin is a reserve antibiotic - erythromycin is in this class |
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macrolides: adverse effects
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diarrhea (prokinetic effect)
other SE's are rare decreased microsomal enzyme activity possible with all but rifampin |
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Lincosamides: chemistry
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hexose containing amides
lipophilic and hydrophilic portions weak base ex. clindamycin |
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Lincosamides: kinetics
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dosed BID - RID
multiple routes of admin (topical - dental; PO) protein bound >70% will distrib. to bone but not CSF fecal excretion > urinary excretion |
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lincosamides: adverse effects
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diarrhea that may be life threatening (guinea pigs, hamsters, rabbits, horses)
- can also cause NM blockade |
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Polyene
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antibiotic antifungal
large MW compound weak acid; amphoteric used only IV highly bound to plasma proteins highly metabolized |
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Anthelmintics
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Avermectins
Benzimidazoles Tetrahydropyrimidines |
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Avermectins
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macrolide
admin: orally/parenteral/topically fecal excretion (stay in body long time) mech. GABA/glutamate action (Cl - channel target) |
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Benzimidazoles
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water insoluble imidazoles
give PO variable absorption through gi tract stays in rumen/fecal excretion action: bind to parasite tubulin safe for host b/c not absorbed |
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tetrahydropyrimidines
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water soluble
can admin PO/parenteral/topically urinary/fecal excretion mechanism: nicotinic agonist lower margin of safety than benzimid. |
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