PHARMACO - Chloramphenicol Flashcards Preview

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Flashcards in PHARMACO - Chloramphenicol Deck (87):
1

?S ribosomes in bacteria

70

2

?S ribosomes in mammalians

80

3

 Basis for selective toxicity against microorganisms without causing major effects on mammalian cells
3 Differences

 Ribosomal subunits
 Chemical composition
 Functional specificities of component nucleic acids and proteins

4

General MoA

Bactericidal

5

General binding at what ribosome

50S except for tetracycline

6

 Inhibits transpeptidation (catalyzed by peptidyl transferase)

chloramphenicol

7

 Blocks the binding of aminoacyl moiety of tRNA to mRNA complex so the peptide at the donor site cannot be transferred to the amino acid acceptor

chloramphenicol

8

 Bind at 50S-block translocation of peptidyl-tRNA from the acceptor site to the donor site

 Macrolides, telithromycin, and clindamycin

9


 Bind to 30S

 Tetracyclines

10

 Blocks the binding of amino-acid-charged tRNA to the acceptor site

 Tetracyclines

11

 Constrict the exit channel on the ribosome through which polypeptides are extruded tRNA synthase activity is inhibited

 Streptogramins

12

inhibits tRNA synthase activity

 Streptogramins

13

bactericidal AB which bind to the 50S

 Streptogramins

14

 Bacteriostatic
 Binds to a unique site at 50S
 Blocks formation of tRNA-ribosome-mRNA complex

 Linezolid

15

Broad spectrum

chloramphenicol
tetracycline

16

moderate spectrum

macrolides
ketolides

17

narrow spectrum

lincosamides
streptogramins
linezolid

18

newer antibiotics

streptogramins
linezolid

19

Are there other antimicrobial drugs in chloramphenicol class

No

20

RoA of Chloramphenicol

 Oral as well as parenteral

21

Tissue distribution of Chloramphenicol

Distributed throughout all tissues

22

Crosses placental and blood-brain barriers

Chloramphenicol

23

Undergoes enterohepatic cycling

Chloramphenicol
tetracycline

24

Enzyme that inactivates chloramphenicol

hepatic glucoronosyltransferase

25

Does Chloramphenicol undergo enterohepatic cycling

Yes

26

Fraction excreted in urine unchanged or changed in chloramphenicol?

unchanged

27

MoA of Chloramphenicol

 Bacteriostatic

28

When does Chloramphenicol become bactericidal

 H. influenzae
 N. meningitidis
 Bacteroides

29

Is chloramphenicol effective for chlamydia

No

30

Resistance to chloramphenicol

 Plasmid mediated-formation of acetyl- transferases that inactivate the drug

31

chloramphenicol is Rarely used as a systemic drug because

of its toxicity

32

Backup drug for severe infections caused by salmonella

chloramphenicol

33

 Treatment of pneumococcal and meningococcal meningitis in beta-lactam-sensitive persons

chloramphenicol

34

 Commonly used as topical agent

chloramphenicol

35

 Sometimes used for ricketssial infections
 Infections caused by anaerobes like B. fragilis

chloramphenicol

36

GI disturbances occur from

direct irritation and superinfection which may lead to candidiasis

37

toxicity of chloramphenicol in the bone marrow

 Inhibition of red cell maturation-decrease in circulating RBC
 Dose dependent and reversible

38

toxicity of chloramphenicol
 Rare idiosyncratic reaction
 Irreversible and maybe fatal

aplastic anemia

39

toxicity of chloramphenicol
 Premature infants
 Deficiency of hepatic glucoronyltransferase
 Tolerated in older infants
 Decreased RBC, cyanosis and cardiovascular collapse

gray baby syndrom

40

enzyme only present in mature liver

hepatic glucoronosyltransferase

41

disease in which all formed elements decrease in level
caused by chloramphenicol

pancytopenia

42

prototype drug of tetracycline

tetracycline

43

drug that must be taken before meals as its absorption is impaired by food and multivalent cation

tetracycline

44

tissue distribution of tetracyclines (narrow or wide)

wide

45

crosses the placental barrier

tetracycline

46

contraindicated in pregnancy because it crosses the placental barrier

tetracycline and chloramphenicol

47

mode of elimination

urine except for ____

48

 All tetracycline drugs eliminated in the urine except for

Doxycycline

49

tetracyline drugs with longer half lives

doxycycline and minocycline

50

what kinds of bacteria do tetracyclines cover

gram (+) and gram (-)

51

type of resistance to tetracyline (2)

 Plasmid-mediated resistance is widespread
 Decrease activity of the uptake systems
 Development of efflux pumps for active extrusion of the drug

52

drug of choice for vibrio cholera

tetracycline

53

Alternative drug for syphilis
Respiratory infections caused by susceptible organisms

tetracycline

54

Treatment of acne

tetracycline

55

most common tetracycline used for the treatment of acne

doxycycline

56

antibiotic for Leptospirosis

tetracycline/doxycycline

57

Prophylaxis against chronic bronchitis

tetracycline

58

Prophylaxis against malaria

tetracycline

59

Selective uses
 Gastrointestinal ulcers caused by H. pylori

 Tetracycline

60

Selective uses
 Lyme disease

Doxycycline

61

Selective uses
 Meningococcal carrier state

Minocycline

62

Selective uses

 Prevention of malaria
 Treatment of amoebiasis

 Doxycycline

63

Selective uses
 ADH-secreting tumors
 Inhibits renal actions of ADH

Demeclocycline

64

Identify which drug has this toxicity
TOXICITY
1. GI disturbances
 Mild nausea and diarrhea to severe, possibly life-threatening colitis
 Disturbances in the normal flora
 Candidiasis (oral and vaginal)
 Bacterial superinfection
 S. aureus or C. difficile
 Rare

tetracyclines

65

Identify which drug has this toxicity
2. Bony structures and teeth
 Fetal exposure
 Tooth enamel dysplasia
 Irregularities in bone growth
 Contraindicated in pregnancy
 Younger children (under age 8)
 Enamel dysplasia and crown deformation when permanent teeth appears
 Bind with calcium and deposit in newly formed bones (impaired long bone formation ) and teeth (discolouration of teeth)

tetracyclines

66

Identify which drug has this toxicity
3. Hepatic toxicity
 High doses in pregnant women and those with preexisting renal disease may impair liver function
 Hepatic necrosis

tetracyclines

67

Identify which drug has this toxicity
Hepatic toxicity - Hepatic necrosis

tetracyclines

68

Identify which drug has this toxicity
4. Renal toxicity
 Fanconi’s syndrome
 Renal tubular acidosis
 Intake of outdated tetracycline

tetracyclines

69

Identify which drug has this toxicity
4. Vestibular toxicity
 Doxycycline and minocycline
 Dose-dependent reversible dizziness and vertigo

tetracyclines

70

3. Photosensitivity
 Demeclocycline
 Enhanced skin sensitivity to ultraviolet light

tetracyclines

71

Rare GI disturbance caused by tetracycline

bacterial superinfection

72

GI disturbance caused by tetracycline

 Mild nausea and diarrhea to severe, possibly life-threatening colitis
 Disturbances in the normal flora
 Candidiasis (oral and vaginal)
 Bacterial superinfection

73

Toxicity in Bony structures and teeth caused by tetracycline

2. Bony structures and teeth
 Fetal exposure
 Tooth enamel dysplasia
 Irregularities in bone growth
 Younger children (under age 8)
Enamel dysplasia and crown deformation when permanent teeth appears
 (impaired long bone formation ) (discolouration of teeth)

74

3. Hepatic toxicity of tetracycline

hepatic necrosis
 High doses in pregnant women and those with preexisting renal disease may impair liver function

75

renal toxicity in tetracycline

Fanconi's syndrome

76


 Renal tubular acidosis
 Intake of outdated tetracycline

 Fanconi’s syndrome

77

Enhanced skin sensitivity to ultraviolet light caused by which tetracycline

Demeclocycline

78


 which 2 AB causes Dose-dependent reversible dizziness and vertigo

Doxycycline and minocycline

79

inhibition of transpeptidation by chloramphenicol is catalyzed by

peptidyl transferase

80

mode of excretion of chloramphenicol

urine

81

Rarely used as a systemic drug

chloramphenicol

82

drug that becomes bactericidal for some strains

chloramphenicol

83

drug that is commonly used as topical agent (As its clinical use)

chloramphenicol

84

cytopenia caused by chloramphenicol is ___-dependent

dose dependent

85

cytopenia caused by chloramphenicol is reversible or irreversible

reversible

86

multivalent cations

Ca, Fe, Al

87

if a patient has gonorrhea, he also has

chlamydia

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