Brainscape's Knowledge GenomeTM

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


See full index

Pharm Block 3 > 10 - Antimycobacterials > Flashcards

10 - Antimycobacterials Flashcards

1
Q

What are some examples of mycobacterial diseases?

A

TB - M. tuberculosis

Leprosy - M. lebprae

Pulmonary, intestinal, lymph nodes - M. avium intracellulare (MAI or MAC)

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

What are the challenges of mycobacterial therapy?

A

Difficult to kill - only vulnerable to cidal drugs when active

Slow growth - hampers identification/susceptibility testing

Lengthy therapy

Intracellular forms

Chronic disease established before symptomatic

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

Why might multiply drugs be needed to treat mycobacterial infections?

A

Spontaneous drug resistance can occur and requires multi-drug therapy with cidal drugs to cure.

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

Describe the cell envelope of mycobacterium?

A

They have a cytoplasmic membrane, a cell wall, and an outer membrane.

The outer membrane contains mycolic acid and arabinogalactan.

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

What are the first line drugs for TB therapy in the US?

A 
Rifampin
Isoniazid
Pyrazinamide
Ethambutol
Streptomycin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What drug is cidal for actively growing cells and inhibitors synthesis of mycolic acid? How does it work?

A

Isoniazid (INH)

Activated by the catalase-peroxidase (KatG protein) and targets the enoyl-acyl carrier protein reductase (InhA protein)

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

What is resistance to isoniazid caused by?

A

Mutations in KatG

Mutations in InhA

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

When should isoniazid be used?

A

All patients infected with INH-sensitive strains should receive INH if possible.

For treatment of active TB, always given in combination.

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

What polymorphisms are associated with isoniazid metabolism?

A

Slow and fast acetylators exist.

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

What are adverse effects of isoniazid?

A

Neurotoxicity, esp/ peripheral neuritis (but can be improved with pyridoxine (VitB6))

Hepatotoxicity (10-20%)

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

What drug works by binding RNA polymerase B and thereby inhibiting bacterial RNA synthesis?

A

Rifampin

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

What are adverse effects of Rifampin?

A

Hepatotoxicity

Potent inducer of multiple CYPs, causing increased metabolism of other drugs.

Orange-red color or urine, feces, saliva, and tears

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

What drug works by interfering with arabinosyl transferase and thereby blocking cell wall synthesis? What is another characteristic of this drug?

A

Ethambutol

It’s tuberculostatic, but doens’t interfere with the cidal effects of other drugs.

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

What are side effects of Ethambutol? Describe its distribution.

A

Gets to adequate levels in the CSF.

Can cause optic neuritis (5-15%)

NOT hepatotoxic

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

What drug blocks mycolic acid synthesis by inhibiting fatty acid synthase I? What are important characteristics of this drug?

A

Pyrazinamide (PZA)

Cidal

Important component of short-term therapy, well absorbed-particularly useful for CNS involvement.

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

What are adverse effects of pyrazinamide?

A

Hepatic damage, especially when combined with rifampin

17
Q

What drug binds to several ribosomal sites to stop initiation and cause mRNA misreading? What is this drug used for?

A

Streptomycin

Usually reserved for the most serious forms of TB

18
Q

What are adverse effects of streptomycin?

A

Ototoxicity - affects both balance and hearing

Nephrotoxicity

19
Q

What are the reasons for simultaneous use of 4 or more drugs to treat TB?

A

Known exposure to drug-resistant strains.

20
Q

What bactericidal drugs are used to treat conventional intracellular and extracellular TB?

A

Isoniazid
Rifampin
Pyranizamide

These are commonly used together because these are -cidal AND intracellular.

21
Q

Describe an atypical mycobacterial infection and how it differs from TB infections?

A

MAC: M. avium-intracellulare complex

MAS is less fatal than TB, so if you find an acid-fast bacilli (AFB) institute an anti-TB regimen until the agent is identified

22
Q

What drug is is used for single-agent prophylaxis of M. avium-intracellulare (MAC) in AIDs patients? What else can this be used for?

A

Rifambutin

Can also be used as an alternate for rifampin in multi-drug treatment of MAC

23
Q

What are the adverse effects of Rifambutin?

A

Similar to rifampin but less frequent.

Drug interactions similar to rifampin, but to a lesser extent (less potent CYP inducer)

24
Q

What cidal drug is part of a multi-drug regimen for treatment of M. avium-intracellulare (MAC) in AIDs patients and can also be used for MAC prophylaxis?

A

Clarithromycin

Cidal

25
Q

What should you do if you have a patient who presents with leprosy (Hansen’s disease)?

A

Consult the national Hansen’s Disease Program in Baton Rouge Louisiana - only specialists should treat leprosy

26
Q

What drug is a structural analog of para-aminobenzioc acid (PABA) and inhibits folic acid synthesis? What is this drug used for?

A

Dapsone

Bacteriostatic; used in combo with other drugs.

Alternative for prophylaxis and treatment of pneumocystis jiroveci in AIDs pts.

27
Q

What is the metabolism of dapsone?

A

Similar to isoniazid, there’s slow and fast acetylators.

28
Q

What are adverse effects of dapsone?

A

Hemolytic anemia and methemoglobinemia.

29
Q

What drug binds to DNA and interferes with reproduction and growth? What is the use of this drug and an adverse effect?

A

Clofazimine

Used in combination therapy

Can cause red-brown pigment of the skin

30
Q

What is the use of rifampin?

A

Widely used in combination therapy.

31
Q

What drugs can be used to treat leprosy?

A

Dapsone
Clofazimine
Rifampin

Pharm Block 3 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions