Antibiotics that Inhibit Protein Synthesis Flashcards

1
Q

Why can high levels of antibiotics that inhibit protein synthesis cause toxic effects for humans?

A

Mammalian mitochondrial ribosome is close to bacterial. High levels of these drugs may cause toxic effects.

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

Who not to give Tetracyclines to

A

Pregnant women
Breast feeding
Kids under 8-12

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

MOA of tetracycline

A

Reversibly bind to the 30s ribosomal subunit. Prevent binding of tRNA.

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

Is tetracycline bacteriostatic or cidal?

A

Static. Will haunt protein synthesis, but not killing.

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

Each of the Tetracyclines have small differences in efficacy and pharmacokinetics. Which tetracyclines are longer lasting?

A

Doxycycline and minocycline.

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

Tetracycline spectrum

A

Considered broad

Will target gram negative and positive

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

Which two drugs are used to treat chlamydial infections?

A

Doxycycline or azithromycin

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

Tetracycline resistant bacteria may be susceptible to others in class. True or false.

A

True. In must cases, you don’t want to prescribe within the same class but ok for tetracycline class.

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

Absorption of tetracycline

A

Bind to calcium, aluminum, iron, and magnesium. Dairy products reduce bioavailability of tetracycline. Avoid antacids or iron supplements with all in this class.

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

Distribution of tetracycline

A

Bind to tissues undergoing calcification- teeth and bones.
Minocycline is the only one to penetrate CSF (but not effective for CNS infections)
Will cross placenta and bind to fetal bones and teeth.

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

Food + tetracyclines?

A

Avoid taking with dairy, iron, or antacid.

Take on empty stomach for better absorption.

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

Elimination of tetracyclines

A

Most are secreted into bile by the liver–> secreted back into GI –> Reabsorbed into intestine –> excreted by kidney (urine)

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

Which tetracycline is not eliminated by the kidney AKA which tetracycline should you prescribe to someone with kidney problems

A

Doxycycline is not eliminated by kidney. Good for patients with renal disease.

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

Are tetracyclines excreted in breast milk?

A

Yes, all of them are. Do not give to pregnant women, breastfeeding women, or kids.

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

Common adverse effects with tetracycline

A
  • Gastric discomfort- avoid dairy and antacids.
  • Discoloration and hypoplasia of teeth in children. Can stunt growth.
  • Photo-toxicity (severe sunburn)
  • Pseudotumor cerebri (headache and blurred vision. Swollen ON bilateral)
  • Superinfections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which drug class can cause pseudo tumor cerebri of bilateral ON

A

Tetracyclines. May report headaches and blurry vision.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Why would you use low doses of doxycyline?

A

Show anti-inflammatory effect. Down regulates pro-inflammatory chemicals. very effective at treating soft tissue inflammation (rosacea, blepharitis, possibly dry eye)

50 mg or less. Does NOT encourage resistance to larger dose.

18
Q

Is ahminoglycosides bacteriostatic or cidal

A

Primarily bactericidal.

19
Q

How are ahminoglycosides administered

A

Usually topically, IV, or IM.
Very polar so oral absorption is inadequate.

Rarely used systemically bc is associated with serious toxicities.

20
Q

What ingredient are people allergic to in neosporin?

A

Neomycin (amino glycoside drug)

21
Q

Which two aminoglycosides can elicit an allergic response?

A

Gentamicin and neomycin.

Not gentle or nice

22
Q

Which aminoglycoside usually doesn’t result in an allergic reaction?

A

Tobramycin

23
Q

Which drug class results in unchanged drug appearance in the urine?

A

Aminoglycosides. Very limited metabolism, then eliminated by the kidneys.

24
Q

Aminoglycosides antibacterial spectrum

A

Effective against aerobic gram negative bacteria (including pseudomonas)

Effective against some gram positive bacteria. Can be combined with B-lactam or vancomycin to improve spectrum.

25
Q

How is resistance of ahminoglycosides caused?

A

Decreased uptake of drug, plasmid associated synthesis of enzymes.

26
Q
Distribution of aminoglycosides
To CNS?
Tissues?
Renal cortex and inner ear?
placenta?
A

Low penetration to CNS and tissues.
High concentration in renal cortex and inner ear.
All cross the placenta

27
Q

Metabolism of aminoglycosides

A

None. Rapidly excreted in urine.

28
Q

Four main adverse effects of aminoglycosides?

A
  1. Ototoxicity. Deafness may be irreversible. Can affect fetus.
  2. Nephrotoxicity. Kidney damage can be severe.
  3. Neuromuscular paralysis. Causes decrease in Ach release. Mainly after large dose.
  4. Allergic reactions. Contact dermatitis very common with neomycin and gentimycin.
29
Q

Macrolide that was developed as an alternative to penicillin G.

A

Erythromycin. Good if allergic to PCN.

30
Q

Drug of choice in macrolide class for chlamydia infections. What is the dose?

A

Azithromycin. 1000 mg one time!

Can either get a 1000 mg powder or 2 500 mg tablets.

31
Q

Mechanisms of macrolide resistance

A

Efflux pumo
Decreased affinity to 50 s subunit
Plasmid associated enzymes.

32
Q

Which macrolide should not be given IV

A

Erythromycin. High incidence of thrombophlebitis. Pain and inflammation at injection site.

33
Q

Macrolide with longest half life, resulting in high volume of distribution

A

Azithromycin. Great penetration into most tissues, Good for eyelid infections (stye)

34
Q

Which two macrolides are extensively metabolized and inhibit oxidation of many drugs

A

Erythromycin and clarithromycin. Cause a lot of drug/drug interactions due to extensive interaction with P450 enzymes.

35
Q

Macrolide adverse effects

A
GI problems 
Acute hepatitis with jaundice 
Ototoxicity 
Caution in patients with arrhythmia 
-azithromycin may be associated with increased risk of cardiac death.
36
Q

Clindamycin MOA. Commonly used to treat what?

A

50 S interference.
Can be used to treat skin and soft tissue infections.
Commonly used to treat abdominal infections associated with trauma (usually caused by anaerobic bacteria)

37
Q

Linezolid used to combat resistant gram ___ organisms

A

positive.

38
Q

MOA of linezolid

A

Inhibits formation of ribosomal complex. Unique binding site means no cross resistance with other drug classes.
bacteria haven’t figured this one out yet.

39
Q

Pharmacokinetics of Linezolid

A

Completely absorbed on oral administration
High volume of dis
No interaction with P450
Renal and non-renal excretion

40
Q

Adverse effets of linezolid

A

Thrombocytopenia- low platelets
Anemia
Optic and peripheral neuropathy.
Can increase serotonin levels. Caution if patient is taking other antidepressants to increase serotonin levels.