Clindamycin Flashcards

1
Q

What is the mechanism of action of clindamycin

A

inhibits protein synthesis by binding to 50S ribosome at the 23S site (like erythromycin)

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2
Q

What are the main uses of clincamycin

A
  • aerobic gram + cocci (staphylococcus and streptococcus)
  • aerobic gram - baccilli (bacteroides and fusbacterium)
  • bonin infectiosn
  • acne
  • MRSA
  • lung abcesses and anearerobic lung and pleural space infections
  • AIDS encephaitis
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3
Q

What is the main side effect of clindamycin that limits its clinical use

A
  • pseudomomembranous colitis and diarrhea
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4
Q

What is the main metabolic pathway of clindamycine

A

metabolized by Cyp P450 enzumes in the liver to the sulfoxide and N-demethylated derivative

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5
Q

PK of clindamycine

A
  • 90% absorbed in the GI tract
  • penetrates and widley distributed in the CNS
  • excreted in the urin and bile
  • hepatic failure dosage adjustment
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6
Q

What is the main adverse effects of clindamycin

A
  • diarrhea
  • nasea
  • vomiting
  • pseudomembranous coitis
  • contact dermatitis
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7
Q

What is pseudomembranous colitis

A
  • overgrowth of C diff that can cause a range of effects ranging diarrhea to colitis and toxic megacolon
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8
Q

How do tetracyclines bind to heavy metals

A

chelates

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9
Q

Why shouldnt tetracyclines be administered with foods that are rich in calcium or other heavy metals

A

chelates make the drugs insoluble in the GI tract

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10
Q

What is the preferred administration of tetracyclines

A

oral absorption is adequate

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11
Q

Why shouldnt children take tetracycliens during the period of permanent teeth formulations

A

chelate calcium, resulting in brown teeth

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12
Q

what is epimerization

A
  • hydrogen on the amine bearing carbon atom is acidic resulting in enolization and epirmerization
  • epitetracyclinc product is inactive
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13
Q

What is the pH of when the rate of epimerization is most rapid

A

4

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14
Q

How is epimerization in the solid state

A

slow

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15
Q

What is tetracycline dehydration

A
  • hydroxyl group at C6 is set up for elimination
  • deactivates and turns into 4-epianhydrotetracycline
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16
Q

What is the toxicity of epianhydrotetracycline

A

can be toxic to the kidneys and can produce fanconi like syndrome

17
Q

Which tetracyclines do not have the 4-epihandrotetracycline metabolite

A

minocyclien and doxycyclein

18
Q

How do tetracyclines cleave under basic solution

A

at pH of 8.5 or above (lactone is inactive)

19
Q

What is the mechanism of action of tetracyclines

A

bind to the 30S subunit aand inhibit bacterial protein synthesis by blocking the A site of the ribosome, resulting in termination of peptide chain growht

20
Q

What are the main advantages of using tetracycline itself

A

binds to the small ribosomal subunit in 6 different locations

its generic and inexpensive

21
Q

What are tetracyclines used for

A
  • acne
  • infections caused by chlamydia, rickettsia, spirochetal infections
  • anthrax, plague, tularemia, legionnaires disease
22
Q

Why is demeclocycline more stable to dehydration

A

has a secondary hydroxyl group at C-6 instead of tertiary hdyroxyl group, dehydrates more slowly due to secondary cation intermediate that is less stable (higher energy)

23
Q

What are the unique effects of minocycline

A

vertigo ataxia nausea

24
Q

Why is doxycycline the tetracycline of choice?

A
  • no potential for 4-epianhydrotetracycline mediated toxicity
  • fewer gi symptoms
25
Q

Why does tigecycline have no potential for 4-epianhydrotetracycline

A

does not have C-^ hdyroxal group

26
Q

what are the toxic effects of tigecyclien

A
  • hepatotoxicity, pancreatitis , anaphyalctoid
27
Q

What is hte MOA of tigecyclien

A

inhibits protein translation in bacteria by binding to 30S ribosomal subunit and blocking entry of amio-acyl tRNA into the A site of the ribosome

28
Q

Why shouldnt sarecycline and omadacycline be administered to pregnant women and nursing

A

can cause fetal harm