LEC 18, 19 - Inhibitors of Protein Synthesis Flashcards Preview

Pharmacology II > LEC 18, 19 - Inhibitors of Protein Synthesis > Flashcards

Flashcards in LEC 18, 19 - Inhibitors of Protein Synthesis Deck (121):
1

What are the adverse effects of tetracyclines? 

Nephrotoxic 

Staining of unerupted teeth 

Superinfections 

GI upset

Anti-anabolic 

Photosensitivity 

Hepatotoxicty 

2

What animals is gentamycin used in?

Pigs, but no other food animals 

3

Tetracyclines (5) 

Doxycycline 

Minocycline 

Tetracycline 

Oxytetracycline 

Chlortetracycline

4

How do ionophores work?

Complex with Na+ in cell membrane 

Produce passive extracellular transport of K+ 

Intracellular influx of H+ 

Kills bacteria + coccidian by lowering intracellular pH 

5

Why is there sometimes an anti-anabolic effect with the use of tetracyclines?

high doses cause binding to mitochondrial ribosomes 

Elevated BUN with pre-existing renal disease 

6

How is linezolid metabolized?

Oxidation but it is non-enzymatic and does not involve hepatic microzome system 

7

how is neomycin used?

Orally for enteric infections (food animal) 

Topically for skin + ear + eye infections 

8

What are tetracyclines used for in small animals medicine?

Respiratory + Urinary tract infections 

Psittacosis in birds

9

How does linezolid work?

Inhibits bacterial protein synthesis by interfering with translation 

10

Why is the use of lincosamides contraindicated in some animals?

Produce severe, often fatal diarrhea due to altered GI flora involving C. Diff

11

What animals is most sensitive to ionophore toxicity?

Horses

12

What is the basic structure of the aminoglycosides?

Contain amino sugars in glycosidic linkage 

Polycations 

13

How is chloramphenicol absorbed?

From GI tract and distributed to all tisuses including CNS and eye 

14

What type of CNS infection is clindamycin used for?

Toxoplasma encephalitis 

15

How are lincosamides adminstered?

PO + Paraenterally + Topically 

16

What are the four major uses for linezolid?

Bacterial pneumonia 

Skin/suture infections 

VRE infections 

MRSA infections

17

What are the regulations when it comes to the use of oxyteracyclines in food animals?

Cattle = 

Extralabel Withdrawl time = 28 days for intrauterine treatment Test milk after intrauterine treatment 

Sheep/goats  = 

Extralabel withdrawl time = 28 days IM/SC treatment 

Milk withdrawl time = 96 hours 

Swine = 

Withdrawal time = 14 days 

 

 

18

What impairs absorption of tetracylcines?

Divalent or trivalent cations 

Avoid milk, antacids, or iron salts for three hours before and after administration 

19

What are the ionophores derived from?

polyther from Streptomyces 

20

What is the distribution pattern of florfenicol?

Widely distributed, including CNS 

21

What does it mean when something has concentration dependent killing?

Increasing concentrations kill an increasing population of bacteria 

More rapid 

Adverse effect are time dependent 

22

How is tylosine adminstered?

IM or PO, BID or SID - Swine + Calves + Lambs + Dogs + Cats

23

What situations are aminoglycosides most often used?

Gram-negative enteric bacteria 

Suspicion of sepsis or endocarditis 

24

What are the three ways that aminoglycosides interact with the 30s subunit causing the block of protein synthesis?

Block initiration of protein synthesis 

Block further translation and elicit premature termination 

Incorporation of incorrect amino acid 

25

What is gentamicin and amikacin used against specifically?

Pseudomonas 

Proteus 

Staphylococcus 

Corynebacterium 

(Wider spectrum of activity) 

26

What are the restrictions to absorption of erythromycin?

Gastric acids destroy base 

need to modify formula for oral admin 

Enteric coated or film-coated 

27

What is pirlimycin used for?

Bovine mastitis 

28

What is the mechanism of action for tetracyclines?

Inhibition of bacterial protein synthesis 

Bind reversibly to 30S ribosomes + prevent access of aminacyl tRNA to receptor site on mRNA-ribosome complex 

Prevents addition of AA to growing peptide chain 

29

How is resistance developed against eryhtromycin?

Active pump mechanism 

Ribosomal protection by inducible or constitutive production of methylase enzymes = modification of ribosomal target 

Macrolide hydrolysis by esterases 

Chromosomal mutations that alter 50S ribosomal protein 

30

What ionophores are used for prevention of coccidiosis in broilers?

Salinomycin 

Narasin 

31

Why does erythromycin react with chloramphenicol and clindamycin?

All these drugs bind to similar spots on the 50s subunit 

32

What is the basic structure of macrolides?

Macrocylic lactone ring which sugars are attached 

33

What are the regulations of chloramphenicol use in food animals? Why?

ILLEGAL 

Due to residue0induced toxicity in humans 

34

Why does iatrogenic endotoxicosis occur with phenicol adminstration?

Rapid killing of gram (-) bacteria 

35

What is lincomycin used for?

Swine - control/txt of swin dysentery 

Treatment of: 

Staphlococcal 

Streptococcal 

Mycoplasmal 

...infectiosn

36

Aminoglycosides (7) 

Neomycin 

Gentamicin 

Amikacin 

Apramicin 

Tobramycin 

Plazomicin 

37

How is clarithromycin administered?

PO, BID - Dogs + Cats + Ferrets 

38

Oxazolidinones 

Linezolid

39

What are the restrictions for tildiprosin when using it with food animals?

Withdrawl time for meat - 21 days 

Do not use in female cattle over 20 months

40

What drugs should not be used with linezolid?

MAO inhibitors 

41

How does plazomicin differ from the other aminoglycocides? 

Devoid of nephrotoxic + ototoxic effects 

Not influenced by bacterial enzymes that modify/inactivate aminoglycosides 

42

What are ways that resistance against aminoglycosides occurs?

Plasmid mediated chemical changes of enzymes that adenylate + phosphorylate + acetylate aminoglycoside drugs 

Resistance may involve alteration of bacterial ribosomes which aminoglycosides attach

Cannot enter the cell

43

What is tildipirosin used for?

BRD - Mannheimia haemolytica + Pasteurella multocida + Histophilus somni 

Control of BRD - MH + PM + HS 

44

What side effects do you see in dogs, cats, cattle, and swine from the use of lincosamides?

Rare 

Neuromuscular blockade at high doses or when used with anesthetics 

45

What is used with clindamycin for preventative purposes? Why?

Metronidazole 

Avoid C. diff-mediated pseudomembranous colitis associated with clindamycin in dogs

46

What is the mechanism of action for lincosamides?

Bind to 50S ribosomal subunits of bacteria = protein syntehsis inhibition 

47

What are the three common tetracyclines used in small animals?

Doxycycline 

Minocycline 

Tetracycline 

48

What is the mechanism of action for erythromycin?

Inhibition of protein synthesis of susceptible bacteria 

Binds reversibly to 50S subunit to prevent translocation of AA 

49

What is the major use of ionophores?

Poultry + swine feed efficiency + anticoccidial activity 

50

What is clindamycin used for?

Dogs/Cats = Peridontal disease + osteomyelitis + dermatitis + deep soft tissue infections caused by gram + infections + TOXOPLASMOSIS 

Dogs = Neoporosis 

51

How is tilmicosin adminstered?

SC, every 72 hours - Cattle 

52

What does it mean to have post-antibiotic effect?

Antibacterial activity persists beyond the time that the antibiotic is measurable 

 

53

how does tobramycin compare to gentimycin?

More potent anti-pseudomonal activity + reduced nephrotoxicity 

54

How do tetracyclines aid in contracted tendons in foals?

Inhibit collagen-based contractions in myofibroblasts 

55

What do ionophores do within the rumen?

Select for Gram + bacteria, shifting the bacterial community to Gram (-)'s  

This increases the production of propionic acid and decreases the production of acetic and butyric acids 

56

What are the adminstration requirements for gamithromycin in food animals?

SC in beef and non-lactating cattle only 

Not for use in female dairy cows over 20months of age or calves that will be used for veal 

57

What specific bacteria do tetracyclines work against in small animal medicine?

Borrelia 

Brucella 

Haemobartonella 

Ehrlichia 

58

How is azithromycin administered?

SID, PO - Dogs + Cats + Foals

59

What are lincosamides active against?

Aerobic gram-positive cocci 

Several anaerobic gram-negative/positive 

60

Why should PO and parenterally admin be avoided in horses?

Danger of disrupting ruminal or colonic microflora 

61

Which of the tetracyclines can pentrate the CNS, eyes, and prostate?

Doxycycline 

Minocyline 

62

How do aminoglycosides get into the cell?

Oxygen dependent transport 

63

Why is it thought that tetracyclines work well with cat absecesses? 

Contain L-form bacteria that lack cell walls and are sensitive to tetracyclines 

64

What are the three important characteristics of aminoglycosides when it comes to their pharmokinetics?

None is absorbed after oral administration 

None pentrate CSF readily 

Normal kidney rapidly excretes them all 

65

How do tetracyclines enter the bacterial cell?

Oxygen-dependent

66

When are tetracyclines used for cat abscesses?

Those that do not respond to B-lactams 

67

What are the characteristics of distribution when it comes to erythromycin? 

Passes through placeneta 

Penetrates prostatic fluid 

DOES NOT GO INTO CNS 

68

Phenicols (2) 

Chloraphenicol 

Florfenicol 

69

What is the protocol for Florfenicol in food animals?

Approved for use in cattle and swine 

Respiratory disease + foot rot in cattle 

70

What is the mechanism of action for chloramphenicol?

Reversibly binds to 50S subunti 

Prevents transpeptidation 

71

What are the five derivatives of erythromycin?

Tylosin 

Tilmicosin 

Tulathromycin 

Azithromycin 

Clarithromycin 

72

Macrolides (6)

Erthyromycin 

Gamithromycin 

Tildipirocin 

Lincomycin 

Clindamycin 

Pirlimycin 

 

73

Why do tetracyclines tend to stain teeth?

Formation of tetracyclein-calcium phosphate complex in enamel and dentine 

74

What is the predominant activity of linezolid?

Aerobic gram-positive organism 

75

What are tetracyclines used for in large animals?

Local + systemic bacterial infections in sheep, cattle, horse, and swine 

Feed additive/growth promoters in cattle and swine 

76

What are the six groups of drugs that act as inhibitors on protein synthesis?

Aminoglycosides 

Macrolides 

Tetracyclines 

Phenicols 

Ionophores 

Oxazolidinones 

77

How is doxycycline secretion diifferent?

Intestinal excretion is major route of elimination

78

Which of the tetracylcines are not nephrotoxic?

Doxycycline 

Minocycline 

79

What is the veterinary feed directive?

Intends to limit antibiotic use for therapeutic needs instead of production

Recommends drug manufacturers VOLUNTARILY stop labeling drugs as "promoting animal growth" 

80

What is the difference between monogastric and ruminal animals when it comes to ionophore absorption?

More complete and metabolism is slower = increased toxicity 

81

What animals is lincosamides contraindicated in?

Horses 

Rabbits 

Hamsters 

Guinea pigs

82

What do aminoglycosides act on?

Inhibiting protein synthesis of susceptible organisms 

Inhibit funciton of the 30S subunit of bacterial ribosomes 

83

What are the distribution characterisitics of clindamycin?

Crosses placenta 

Gets into breast milk 

Reaches high concentrations in teh bone 

Does not get into the CNS

84

How are ionophores excreted?

Bile 

Elminated by feces 

85

What is a good way to get aminoglycocides to work against gram +'s?

Use with beta lactam 

86

Which of the phenicosl produces aplastic anemias?

Chloramphenicol 

87

What are the adverse effects of chloramphenicol?

Dose dependent 

bone marrow depression 

Gray syndrome 

Due to inhibition of protein synthesis in host mitochondria 

88

How is florfenicol metabolized?

1/3 metabolized by the liver 

2/3 of drug excreted as parent 

89

What is chloramphenicol used for in dogs, cats, horses, ad birds?

Local and systemic infections 

Respiratory + CNS + Ocular 

Due to Anaerobes + Salmonella 

90

What are the adverse reactions to erythromycin?

GI upset 

Pyresis 

Reversible jaundice 

Elevated hepatic enzymes 

Allergic reactions 

QT prolongation 

91

How is florfenicol given to swine?

Drinking water 

92

What is the absorption rate of tetracyclines? What is the exception?

60 to 90% 

Cholortetracycline - 35% 

 

93

When are macrolides effective?

Alternative agents to penicillin when patient is allergic and/or when in renal failure 

94

What are the adverse effects of the penicols?

Anemia 

Aplastic anemia 

Iatrogenic endotoxicosis 

 

95

How are tetracyclines excreted?

Glomerular filtration, with small amounts being excreted into the bile 

96

How is erythromycin administered?

PO or IM TID - Dogs + cats + foals 

IM SID - Cattle + Sheep + Swine 

97

What does tetracycline work against?

Gram +/- aerobes/anaerobes 

Rickettsiae 

Spirochetes 

Chlamydiae 

Mycoplasma 

Some protozoans 

98

How is linezolid adminstered?

IV or Oral

99

What does plazomicin act against?

Klebsiella pneumoniae 

Escherichia coliUse 

100

What is the major characteristic of aminoglycocides that give them their properties?

Polarity 

101

How is erythromycin excreted?

Lost in feces in large amounts 

5% excreted in urine 

102

What two drugs have contraindications with erythromycin?

Chloramphenicol 

Clindamycin 

103

What is gamithromycin used for?

BRD - Manneimia haemolytica + Pasteurella multocide + Histophilus somni + Mycoplasma bovis 

Control of BRD - M.H. and P.M. 

104

What are the characteristics of metabolism for tetracyclines? Which one differs and how?

Metabolism is very minimal in domestic animals 

Exception = minocylcine, metabolized by the liver 

105

How is florfenicol given to cattle?

IM, one dose than another 48 hours later 

Slow-release prep

106

How is tulathromycin administerd?

one SC injection against cattle and swine respiratory infectiosn 

107

What are the gram negative rods that aminoglycocides are most effective against?

Enterbacteria 

Proteus 

Psudomonas 

Serratia 

108

What ionophores are used in the feed for growth promotion and feed efficiency?

Monensin 

Lasalocid 

Laidlomycin 

109

What are the three lincosamides?

Lincomycin 

Clindamycin 

Pirilmycin 

110

What specific bacteria do tetracyclines kill in large animals?

Chlamydial 

Rickettsial 

Protozoal 

111

What drug are lincosamides mixed with to treat toxoplasmosis?

Pryimethamine 

112

When is chloramphenicol bacteriocidial?

Meningeal pathogens 

H. Influenzae 

Neisseria meningitidis 

Streptococcos pneumoniae 

113

How does chloramphenicol cause aplastic anemia in humans?

Idiopathic 

Why it is banned in food products 

114

What three tetracyclines are most commonly used in large animals?

Tetracycline 

Chlortetracycline 

Oxytetracycline 

115

Ionophores (5) 

Monensin 

Lasalocid 

Laidlomycin 

Salinomycin 

Narasin 

116

When are aminoglycosides bactericidal?

Aerobic conditions, unknown why

117

What two tetracyclines are used for cat abscesses?

Doxycycline 

Minocycline 

118

Where do superinfections caused by tetracyclines tend to occur?

Gi tract 

due to prolonged adminstration 

119

How is chloramphenicol metabolized?

Glucuronide conjugation 

75% for cats 

90% for dogs 

120

How should aminoglycosides be given since that have a large PAE?

Single, large dose will be the most efficective 

121

Why does chloramphenicol cause anemia?

Dose-related 

Inhibits the uptake of iron in mitochondira present in erythropoeitic cells in bone marrow