Pharma Midterm 3 Flashcards
unique targets example of action
- inhibition of cell wall synthesis (B-lactam)
- Fungal cell membrane component:
- folic acid synthesis (sulfonamides)
similar targets action
dihydrofolate reductase
protein synthesis inhibitors
protein synthesis inhibitor acting on 30S subunit
- tetracyclines
- Aminoglycosides
protein synthesis inhibitor acting on 50S subunit
- Macrolides
- Phenicols
Example of drug having dose dependent toxicity, high dose effect
Phenicols, can cause bone marrow suppression
Common target drugs example
Primary antineolastic agents
antiparasitic drugs (cholinergic substances)
Example of Category A drug TOTALLY banned, target animals
Vancomycin; for small animals
Category B drugs
- fluroquinolones
- 3-4th generation cephalosporin
- colistin
Category C drugs, target animals
Macrolides, phenicols
smalls & Food producing
Category D drugs
tretracyclines
penicillines
Meaning of MIC (describing efficacy)
Concentration of antibacterial where Bacteria cannot GROW
Meaning of MPC (describing efficacy)
Concentration of antibacterial where we won’t select any mutant/resistant bacteria
Meaning of MBC (describing efficacy)
Concentration of antibacterial where Bacteria can be killed
Example of bactericidal
Aminoglycosides
Polypeptides
Fluoroquinolones
Metronidazole
Example of bacteriostatic
Tetracycline
Macrolides
Phenicols
(Post Traumatic Mouvement)
Define Postantibiotic effect
delayed antibacterial effect after concentration of the drug declined below the MIC (usually against Gram +)
define Synergistic, give example
Potentiate each other
penicillin + streptomycin
define additive, give example
broaden spectrum
gentamicin + metronidazol
define antagonist, give example
fights for the same subunit
erythromycin + florfenicol
Examples of transferring resistance between bacteria
- conjugation
- transduction (via bacteriophages)
- transformation (from dead bacteria)
List the 5 resistance mechanisms
- antibiotic degrading enzymes (penicillinase)
- antibiotic transforming enzymes
- increasing integrity of cell wall
- increased efflux pump expression
- modifying binding sites (MRSA)
List the antibacterial agents that are inhibitor of protein synthesis
- aminoglycosides
- tetracyclines
- macrolides
- lincosamides
- pleuromutilins
- phenicols
which type of tetracyclines have the best properties? Examples
Semisynthetically, doxycycline/minocycline
Short acting tetracyclines, (daily dose)
tetracyclines
oxytetracycline
chlortetracycline
(applied BID)
intermediate acting tetracycline
demeclocycline
long acting tetracycline + (daily dose)
Doxycycline
minocycline
(SID)
structural specificity of tetracyclines
lipophilic compounds because of 4 rings (moderate lipophilic)
mécanisme of action of tetracyclines (normal concentration)
inhibition of protein synthesis (30S subunit)
mechanism of action tetracyclines at high concentration
bacterialcidal, loss of functional integrity of cytoplasmic membrane
mode of action of tetracyclines
bacteriostatic
tétracycline resistant bacteria specie
E. Coli,
Salmonella spp.
Past. multocida
Manheimia haemolytica
Staphyloccocus aureus
streptococcus
antimicrobial spectrum of tetracyclines
aerobic &anaerobic
Gram + & -
(all bacteria types)
tétracyclines are very effective against
- mycoplasme
- rickettsiae
- chlamydophilae (zoonotic)
- Wolbachia spp. (bact. in heart worm)
- Borrelia spp (lyme’s)
- bordetella bronchiseptica (kennel cough)
drug of choice against Mycoplasma haemofelis
tetracyclines
drug of choice against anaplasma phagocytophilum
tetracyclines
how to treat heart worm
to avoid cytokine storm, should be killed very slowly
- doxycycline for 1 month : 10mg/Kg, BID
Can tetracycline be effective against protozoa
yes, most common in Hungary Babesia spp.
mechanism of resistance against tetracyclines
- impaired uptake into bacteria
- active efflux
bacterial tetracycline resistant ovo
- pseudomonas aeruginosa
- mycobacterium
tetracyclines acquired resistancy
E.Coli
Salmonella spp.
Pasteurella multocida, Mannheimia Haemolytica (Gram -)
Staphylococcus aureus, streptococci (Gram +)
administration of tetracyclines
often used orally, but bioavailability bad (5-10%)
action of short acting tetracyclines not good
AMEG classification of tetracyclines
D category “Prudent”
Long acting tetracyclines ADME
A= Excellent
D= Excellent (bone & can cross BBB)
M= low degree
E= mainly large intestine, bile
Classic Tetracyclines ADME
A: (10%) moderate, impaired by food
D: Good (bone)
M: Low degree
E: mainly urine
Indications of tetracyclines
- Bronchopneumonia
- Foot disease
- Metritis, mastitis
application of tetracycline for foot diseases
spray form
Specific conditions treated with tetracyclines
- Lyme disease (doxy, 6-8 weeks)
- chlamydophilosis
- feline mycoplasmosis
- infectious keratoconjunctavitis in cattle
- proliferative enteropathy in horses
- heartworm
- heartwater
-nocardiosis - anaplasmosis
Side effects of tetracyclines
- GI disturbance
- Dysbacteriosis
- collapse, hyperkalaemia (rapid IV injection)
- tissue necrosis (IM)
- yellow discoloration of teeth
- photosensitivity
- hepatotoxicity (high concentration)
Which phenicol is prohibited in food producing animals
Chloramphenicol
which phenicol is only used in poultry industry
tiamphenicol
which phenicol is widely used in farm animals
Florfenicol
structural specificity of phenicols
Lipophilic, small molecules (have excellent pharmacokinetic properties)
Mechanism of action of Phenicols
inhibition of protein synthesis (subunit 50S)
Mode of action of phenicols
Bacteriostatic
what are the mechanisms of resistance of phenicols
- impaires uptake into bacteria
- active efflux
- Acetyl transferase (enzymes modify the structure of drug)
Antimicrobial spectrum of phenicols
broad
Aerobis & anaerobic
Gram + & -
which drug is the only authorized in fish against Aeromonas salmonicida & Vibrio anguillarum?
Florfenicol
AMEG classification of phenicols
C category “caution”
Can phenicols be used against Chlamidophila & Rickettsia
yes, but TTC are first choice (cheaper, more effective & cat D.)
ADME of phenicols
A: Excellent (oral = IM/SC)
D: Excellent
M: extensive in liver
E: urine (inactive) & bile
Classification of different Half lives of phenicol
ruminants > swine > cat > dog
Administration of phenicol in Ru
every 2nd day
daily Administration of phenicol in Su
once daily
Administration of phenicol in feline
BID
Administration of phenicol in canine
TID
Side effects of phenicols
dose dependent : liver
Anaemia
CHLORAMPHENICOL - aplastic anaemia
long term: immunosuppression
pain at injection site (IM)
indication of phenicols for FPA
mainly Food producing animal (florfenicol):
Respiratory disease
foot disease
infectious keratoconjunctivitis
fish aeromonas infection
indication of phenicols for small animals
eye infection
prostatitis
meningitis
MRSA infection
chemistry of macrolides and outcome
lactone ring with sugar = lipophilic & weak base
so ion trapping inside cells and high IC concentration
Macrolides distribution
broad, but not to brain
mechanism of action of macrolides
Inhibition of protein synthesis (50S)
mode of action of macrolides
Bacteriostatic
(bactericidal high concentration, IC and Respiratory tract pathogens)
Resistance to macrolides
not so common,
decreased permeability
degrading enzymes
modified binding sites (cross resistance with lincosamides & phenicols)
Name of macrolide with 2 nitrogen
azalide
- AZITHROMYCIN
- gamithromycin
name of macrolide with 3 nitrogen
triamilide,
- tulathromycin
antimicrobial spectrum of macrolides
Gram +
Gram - (anaerobic):
- fastidious
- Campylobacter
- Brachyspira hyodysenteria
- Lawsonia intracellularis
- Bordetella bronchiseptica
- mycoplasma, chlamydophila
- Borrelia
- Rhodococcus equi
what are the Gram - fastidious bacteria (6)
Pasteurella
manheima
histophylis
haemophylis
actinobacillus
For which indication should tyrosine phosphate be used & why
Swine enteric disease : because only 15% bioavailability
For which indication should tyrosine tartarate be used and why?
Swine respiratory disease : because 30% bioavailability
IM and SC macrolides are used for which animals
Ruminants and swine
How are macrolides given to horses, dogs and cats?
orally
most important fact about distribution of macrolides
Resp. tract (tonsillae)
intracellular
Which other drug should macrolides NEVER be combined with
ionophor antibiotics
Excretion of macrolides
90% by the bile
macrolides side effects
GI irritation (vomiting, diarrhea)
dysbacteriosis (horses, rabbit, herbivore rodents)
tissue irritation
macrolides cannot be used in horses (T/F)
True in adult horses, can be used in foals as they haven’t developed their intestinal flora
indication of erythromycin
horses: R. equi (+rifampicin
smalls: campylobacteriosis
indication of spiramycin
smalls: oral cavity infections
large: mastitis (but tissue irritation & long WP)
why is tyrosine less used
frequent resistant
indication of tylosin
(past) swine dysenter
lawsonia intracellularis
(su, ru, poultry) resp tract infection, necrotic enteritis
smalls: ONLY ARD in ca
per os
which is the most cardiotoxic macrolide
Tilmicosin
indication of tilmicosin
ONLY, Ru (SC) & Su(Po)
fastidious Gram - & Mycoplasma
indication for tylvalosin
per os
Su & poultry
- B. hyodysenteria
- L. intracellularis
- Mycoplasmae
- Fastidious Gram -
Tulathromycin, gamithromycin indications
Ru & Su (injection)
fastidious organisms
mycoplasmae
RESP TRACT INFECTIONS
long acting
Tildipirosin indications
Ru & Su
RESP TRACT INFECTIONS
long acting
indications for Azithromycin & clarithromycin
for Smalls, Hu & Eq
- Gram +
- Fastidious gram -
- Borrelia, Mycoplasmae, campylobacter, R. Equii
good lung concentration
General properties of lincosamides
inhibition of 50S
Bacteriostatic
cross resistance w/ macrolides & phenicols
good absorption,distribution (not BBB) excreted by bile & urine
toxicity of lincosamides
tissue irritation
DYSBACTERIOSIS
prohibited for horses, rabbit, herbivore rodents
Lincosamides spectrum
gram + & anaerobic
B. hyodysenteriae, L. intracellularis
Mycoplasmae
Campylobacter
Lincosamide drugs
Lincomycin
Clindamycin
Pirlimycin
lincomycin indication
Food prod animals (injection)
- foot rot, wounds, mastitis, swine dysentery, respiratory tract
clindamycin indication
smalls
- dermatitis, abscesses, oral cavity
- anal sacculitis (anaerobic bact)
- osteomyelitis
Indication for Pirlimycin
mastitis
Pleuromutilins drugs
tiamulin, valnemulin
tiamulin cannot be combined with …
ionophore anticoccidials
G properties of pleuromutilins
inhibition of 50S
Bacteriostatic
cross resistance w/ macrolides & phenicols
good absorption,distribution (not BBB) excreted by bile & urine
toxicity of pleuromutilins
skin erythema
vulvar edema
(from urine)
pleuromutilins spectrum
Gram +
Fastidious
B. hyodysenteria, L. intracellularis
Mycoplasmae
pleuromutilins indications
- swine dysentery
- proliferative enteropathy
- mycoplasmosis + resp (su & poultry)
mode of action of cephalosporins
bactericidal time dependent
how can there be cephalosporin resistancy
- ab ovo
- b-lactamase production
- PBP (penicillin binding proteins) mutation
cephalosporin spectrum
different according to generations
gram -»_space;> 4th
1st ««_space;gram +
oral 1st generation cephalosporin
cephalexine
cephadroxil
parenteral 1st generation cephalosporin
Cephapirin
Cefalonium
Cephalotin
cephazoline
1st generation cephalosporin is similar to
amoxicillin
2nd generation cephalosporin spectrum
- Gram - (against lactamase producers)
E.coli, Salmonella, Klebsiella - Anaerobic bacteria
3rd generation cephalosporin spectrum
weak Gram +
Gram - (most lactamase producers) + Pseudomonas aeruginosa
fastidious & anaerobic (pasteurella, manhemia)
4th G. cephalosporin spectrum
- Gram +
- Gram - (lactase prod)
(more active if MICs are lower) - fastidious & anaerobic
Absorption of cephalosporin
oral & parenteral
excretion of cephalosporin
kidney
Bile : cefoperazone, ceftriaxone & cefaclor)
cephalosporin side effects
- allergy (eq. moderately tolerates)
- dysbacteriosis
- haematological
- mild nephrotoxicity (if combined with AG)
indication of 1st generation cephalosporins
- mastitis/metritis
- dermatitis, soft tissue infection
- Resp infection
- UTI
(- preoperative : cephalozine) surgery > 1h
Oral 2nd G. cephalosporins
Cefuroxine axetil
Cefaclor
Parenteral 2nd G. cephalosporin
Cefuroxime
cefotetan, cefoxitin (anaerobic)
2nd G cephalosporin indication
Dermatitis, soft tissue irritation
Resp infection
UTI
3rd G cephalosporin oral
Cefixime
parenteral 3rd G cephalosporins
- Cefoperazone
- Ceftiofur
- Cefovecin
- cefotriaxone & Cefotaxime (bone + brain & 2nd choice limes disease)
3rd G Cephalosporin indication
- dermatitis, soft tissue infections (cefovecin)
- Resp infection
- UTI
- Menangitis, encephalitis (cefotriaxone)
- osteomyelitis (cefotriaxone)
AMEG categories for cephalosporins
Cat. B : 3rd & 4th G
Cat. C : 1st & 2nd G
2 Other b-lactam ABs other than cephalosporins
Monobactams
Carbapenems
Aztreonam
Tigemonam
- parenteral
- p.o.
Cat A
primary UTI
Imipenem & meropenem
IV or IM
LAST RESORT AB (cat A)
highly active against all important pathogenic bacteria.
structure of aminoglycosides
hydrophilic, eliminated by urine (so liver not included)
Mechanism of action of aminoglycosides
- cell membrane toxicity (oxidative stress)
- RNA-structural damage
do not give against anaerobic bacteria (O2 is needed)
Mode of action of aminoglycosides
BACTERICIDALE concentration dependent
( spectinomycin has bacteriostatic effect)
good PAE (4-6 hours)
aminoglycosides spectrum
gram - aerobic
- staphylococcus
- mycobacterium
micoplasma (spectinomycin)
pseudomonas (gentamycin)
order of using aminoglycosides in case of resistant bacteria
Streptomycin > Neomycin > Gentamicin >Tobramycin, amikacin
Absorption of aminoglycosides
p.o., parenteral, IV (if life threatening)
distribution of aminoglycosides
systematic
excretion of aminoglycosides
active form in urine (nephrotoxic must check if patient is hydrated)
list aminoglycosides from most toxic to least
Neomycin > Gentamicin > Streptomycin > Amikacin > Spectinomycin
With which other drugs should aminoglycosides not be combined with
muscle relaxants
furosimide
indications of aminoglycosides
- Resp infections
- GI infection (esp enterobact)
- UTI
- Mastitis
- Dermatitis
- topical administration (eye, ear)
- septicaemia
- leishmaniasis
Streptomycin
not alone, combined w/ penicillins
Su, Smalls
mastitis
1-3days
Neomycin
alone & w/ penicillins
GI infections, mastitis
poultry & Su
not recommended to use systemically (most toxic) p.o. & topical
Framycetin
component of neomycin produced by streptomyces fradiae
ear & eye infection
mastitis intrammamry infusion
Gentamicin
alone
GI infection, mastitis
against pseudomonas aeruginosa
Netilmicin
same as gentamicin:
GI infection, mastitis
against pseudomonas aeruginosa
but less ear & kidney toxicity and less activity against pseudomonas
+ lower respiratory tract infection
Spectinomycin
poultry, Su
bacteriostatic
mycoplasma spp
GI infection
Apramycin
p.o. bioavailability is better
Su
e.coli, diarrhea
Tobramycin
toxic
Topical, parenteral
Pseudomonas aeruginosa
Amikacin
parenteral only
pseudomonas aeruginosa
MRSA, MRSP (only one)
paromycin
antiprotozoal treatment too
reduces effect of cryptosporidium parvum
antileishmanial
aminoglycosides AMEG cat.
Category C, except spectinomycin (D)
what is today’s most used penicillin
Amoxicillin
Structure of Penicillins
B-lactam ring & thiazolidine ring
mechanism of action of penicillins
inhibition of cell wall synthesis
peptidoglycan structure & the bonds
- N-acetyl - muramic acid/glucose amine chain
- transpeptide bonds: transpeptidase, carboxipeptidase (PBP)
mode of action of penicillins
bacteriocidal time dependent, act on dividing bacteria where new cell wall is synthesised (slow acting)
can penicillins be combined with bacteriostatic?
no, will have no way of killing bacteria
Why is it easier for penicillin to act on Gram + then Gram -
PBPs are located btwn cell wall & cell membrane , must reach and it is easier to penetrate gram + then gram -
how can a bacteria have a ab ovo resistance
- microplasma (no cell wall)
- clamydia, brucella (brutal cell wall)
how can we inhibit a B-lactamase production
adding clevulonic acid
example of strains of bacteria having a PBP- gene mutation
MRSA, MRSP strains
Narrow spectrum penicillins spectrum
most gram +
Gram - fastidious (PMHHA)
leptospira, borrelia spp
anaerobes
Narrow spectrum penicillins active substances
- Benzylpenicillin (Na,k / procaine / benzathine)
- Phenoxymethyl - penicillin (orally)
- penethamat (milk)
ADME of narrow spectrum penecillins
A: oral (Phenoxymethyl - penicillin) otherwise parenteral
D: poor (not for intracellular)
M: hydrophilic so minimal (urine)
E: active form in urine
side effects of procaine penicillin
piglets & foals are sensitive (lack procainase enzyme in liver)
indication of narrow spectrum penicillins
- resp infections
1st choice for: Swine erysipelas
anthrax
tetanus
necrotic enteritis
streptoccocis
Penicillinase stable penicillin active substance
Methicillin (acid sensitive)
Oxacillin, Cloxacillin, Dicloxacillin, Flucloxacillin, Nafcillin
O C D Fucks Neurons
indication of penicillinase stable penicillins
dermatitis
mastitis
staphylococcus & streptococcus
Extended spectrum penicillins spectrum
Gram + bacteria
Several Gram - (Fastidious, E.coli & salmonella, leptospira, borrelia)
extended spectrum penicillins active substances
amoxicillin
ampicillin
COmbination with amoxicillin
Clavulanic acid
Combination with ampicillin
Sulbactam (B-lactamase inhibitor)
oral absorption of ampicillin
weak (why it is not used)
feed reduces
oral absorption of amoxicillin
good - excellent
penicillins acting against pseudomonas spp.
- piperacillin + tazobactam
- ticarcillin
- carbenicillin
AMEG classification of penicillins
- A: antipseudomonas
- C: Extended spectrum
- D: narrow & extended spectrum