Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

pharmacology 3 > inhibitors of protein synthesis > Flashcards

inhibitors of protein synthesis Flashcards

1
Q

name the eye ointment name of tetracyclines

A

terramycin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

why are they called “tetracyclines”?

A

they are called tetracyclines because they have 4 rings that are fused to each other. in addition to this they have 4 R groups that impart activity to the structure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the MOA of tetracyclines

A

they enter by passive diffusion and an energy dependant transport protein. they bind reversibly to the 30 S subunit of bacteria thereby inhibiting bacterial protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

name the tetracycline drugs

A

tetracycline capsules 250 mg
oxytetracycline terramycin eye ointment
doxyclycline doxydar capsules 200 mg and IV injection
minocycline minocin capsule 100,200 mg and IV injection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

tetracyclines should not be taken with specific products? name them and give reason why?

A

tetracyclines should not be taken concomitantly with
dairy products, aluminium and magnesium antacids or iron preparations because it decreases the absorption of tetracyclines due to formation of non absorbable chelates.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

describe the absorption of tetracyclines

A

they are absorbed adequately but incompletely orally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

tetracyclines should be administered

a. with food
b. without food

A

b. without food

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

where do tetracyclines concentrate

A

in the liver, kidneys, spleen, skin and tissues undergoing calcification (teeth and bone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

do tetracyclines enter the CSF

A

yes but in inadequate therapeutic concentrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

do tetracyclines cross the placental barrier, where do they concentrate in foetus

A

yes, they concentrate in the fetal bone and dentition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how are tetracyclines excreted

A

they are secreted in the bile. reabsorbed in the intestine and excreted in the urine by glomerular filtration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

which tetracycline would you recommend to a patient with compromised renal function and why? name the component excreted.

A

recommend doxycycline because it is preferentially excreted in bile via feces.
doxycycline glucoronide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

only ____________ provides therapeutic concentrations in the CSF.

A

minocycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

any organism resistant to one tetracycline is resistant to all. true or false

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

give 2 reasons for resistance to tetracyclines?

A

inability of the drug to accumulate due to the R factor, energy dependant efflux pumps
enzyme modification of tetracycline binding site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the adverse effects of tetracyclines

A 
GI disturbance 
staining of teeth 
hyperplasia 
bone deformities 
fatal hepatotoxicity 
phototoxicity
superinfection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the CI of tetracyclines

A

pregnant women
first trimester : abnormal skeletal development of baby
2nd and 3rd trimester ; dental discolouration and maternal hepatotoxicity
lactating females : drug may pass to baby via breast milk leading to dental discolouration and abnormal skeletal development
renally impaired patients except doxyclycline
children under 8 yrs : dental discolouration and abnormal skeletal development

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

name the aminoglycoside drugs

A
  1. streptomycin (streptomycin sylfate injection)
  2. trobramycin (nebcin injection)
  3. netromycin/netilmicin (netromycin sulfate injection)
  4. neomycin (neomycin and bacitracin cream)
    neospora ( gramicidin + neomycin) eye drops
  5. amikacin (amikin) injection
  6. gentamycin, genticin ear and eye drops, garamycin sulfate inj. and garamycin eye drops
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

aminoglycosides have been the mainstays of treatment for?

A

the serious infections caused by aerobic gram negative bacilli.

20
Q

aminoglycosides have a broad therapeuic index. true or false?

A

false. they have a narrow therapeutic index

21
Q

why are aminoglycosides rarely used

A

due to their serious toxicities

22
Q

aminoglyclosides are now replaced with :

a. vancomycin, bacitracin, penicillins
b. 3rd gen cephalosporins. fluroquinolones, imipenem/cilastatin
c. imipenem, cilastain, penicillins

A

b. 3rd gen cephalosporins, fluoroquinolones and imipenem/cilastatin

23
Q

what is the MOA of aminoglycosides

A

aminoglycosides bind to the 30S ribosomal subunit leading to

a. inhibition of the initiation of protein synthesis
b. misreading of mRNA leading to abnormal proteins. or premature chain termination

24
Q

aminoglycosides are

a. bacteriostatic
b. bactericidal

A

b. bactericidal

25
Q

why do aminoglycosides not work against anaerobic micro organisms?

A

because anaerobes do not have an O2 dependant carrier system. susceptible organisms have an oxygen dependant system that tranports the antibiotic across the cell membrane.

26
Q

what is the synergistic relationship between aminoglycosides and beta lactam?

A

beta lactam destroys the cell wall allowing aminoglycosides to enter and inhibit protein synthesis

27
Q

what are the typical therapeutic indications of aminoglycosides

A

enterococcal infections : gentamycin/stretomycin + vancomycin/ other beta lactam
psuedomonas infection : tobramycin alone or tobramycin + antipseudomonal penicllin eg. piparcillin

28
Q

name the macrolides

A
  1. erythromycin
    erythrocin tablets, erythrocin syrup, erythromycin injection
  2. clarithromycin, klacid tablets, klacid powder for suspension
  3. azithromycin, zithromax capsules, zithromax oral suspension
29
Q

what is MOA of macrolides

A

they act by binding irreversibly to the 50 S subunit of bacterial ribosome and inhibiting the translocation step of bacterial protein synthesis

30
Q

name the therapeutic indications of erythromycin

A

Used in oral infections, urethritis, respiratory tract diseases (including Legionella), skin infections, chronic prostatitis, diphtheria prophylaxis and carrier state, acne vulgaris.

31
Q

clarithromycin is additional active against which organisms?

A

H. influenzae and intracellular pathogens such as chlamydia. legionella and ureaplasma

32
Q

_____________ is used as treatment in H.pylori eradication regimen.

A

clarithromycin

33
Q

azithromycin is not as effective as erythromycin against ________ and _________.

A

streptococci and staphylococci

34
Q

if the bacteria is resistant to erythromycin, can we administed azithromycin/clarithromycin? why?

A

no because Both azithromycin and clarithromycin show cross resistance with erythromycin

35
Q

name the adverse reactions of macrolides

A

epigastric distress
cholestatic jaundice
ototoxicity (transient)

36
Q

what happens when azithromycin and clarithromycin eliminate the intestinal flora?

A

the intestinal flora that inactivates digoxin is eliminated hence this leads to digoxin toxicity.

37
Q

describe the MOA of chloramphenicol

A

binds reversibly to 50S ribosmal unit of bacteria and inhibits peptidyltransferase enzyme

38
Q

why does chloramphenicol cause bone marrow toxicity at high doses?

A

this is due to the similarity between the organelles and due to inhibition of mitochondrial protein synthesis

39
Q

describe the antibacterial spectrum of chloramphenicol

A

Broad spectrum, effective against bacteria and other microorganisms including anaerobes (except chlamydia and pseudomonas)

40
Q

describe the resistance towards chloramphenicol

A
  1. inability of the antibiotic to penetrate the enzyme

2. prescence of an enzyme that inactivates chloramphenicol

41
Q

what are the adverse reactions of chloramphenicol

A 
Hemolytic anemia in G6PD deficient patients
Reversible anemia (dose related)
Aplastic anemia (dose independent)
hepatic enzyme inhibition 
gray baby syndrome
42
Q

why does gray baby syndrome occur with chloramphenicol?

A

Occurs due to inability of the baby to glucuronidate chloramphenicol effectively if doses were miscalculated.

43
Q

describe the MOA of clindamycin

A

They act by binding irreversibly to the 50S ribosomal subunit of bacterial ribosomes inhibiting the translocation step in bacterial protein synthesis.

44
Q

describe the therapeutic indications of clindamycin

A

Used in bone and joint infections, peritonitis and endocarditis prophylaxis
infections caused by Bacteroides fragilis
in acne caused by Propionibacterium acnes
dental infections or prophylaxis prior to dental procedures

45
Q

clostridium difficile is resistant to clidamycin. this might cause _____________.

A

pseudomembranous colitis

46
Q

what is the resistance mechanism of clindamycin

A
  1. inability of the antibiotic to penetrate organism.
  2. decreased affinity for 50 s ribosomal subunit.
  3. plasmid associated synthesis of esterase enzyme.

pharmacology 3 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions