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Flashcards in TB drugs Deck (21):
1

Should you use a multi-drug therapy for treating active Tb?

yes
-enhance rates of response/cure
-reduce emergence of resistance

2

Can isoniazid HCl (INH) be used alone?

not used as a single drug to treat TB
-usually in combo with at least 2 other drugs

3

What are two ways that there can be resistance against Isoniazid HCl (INH)

1. Mutations in katG gene
-catalase-peroxidase-->INH activation

2. Mutation of inhA gene-->cell wall (mycolic acid) synthesis

4

Can rifampin be used alone?

no because of rapid development of resistance

5

What are the mechanisms of resistance for rifampin?

inhibits DNA dependent RNA polymerase, encoded by the rpoB gene
-rpoB mutations can cause rifampin resistance

6

Does rifampin interact with other drugs? How?

yes
it induces hepatic microsomal enzymes
-accelerates the clearance and reduces effective serum concentrations
-coumadin, estrogen, anti convulsants, antiretroviral drugs

7

What are two toxicities ethambutol can cause?

optic neuritis-blurred vision, central scotomata, red-green color vision loss, dose-related

peripheral neuropathy less common-feet, hands

8

What is ethambutol?

first like tb helper drug

9

Pyrazinamide is used for how long?

first line drug used for the 1st two months of therapy

10

What is primary resistance?

infection by a source case with drug-resistant tb
(acquired at infection)

11

What is secondary resistance?

from ineffective therapy
-too few drugs to prevent emergence of resistance
suboptimal drug dosing or absorption-->selection for resistnace

12

The risk of evolution of resistance to two drugs is what of the risk of the development of each drug?

product
you add them

13

What is multidrug resistant TB?

resistant to both INH and rifampin
-more common in HIV
-nosocomial transmission and high mortality in HIV/AIDS

14

What does not being able to use rifampin do to duration of therapy?

eliminates short-course (6 month) TB therapy
-->requires at least 18-24 months

15

What is extensively resistant TB?
not on list

resistant to all the following:
INH and rifampin
fluoroquinolone
one of three injectable antibiotics (amikacin, kanamycin, capreomycin)

16

What is the 6 month treatment regimen of Tb treatment?

RIPE
R=rifampin
I=INH
P=PZA
E-Ethaambutol

Initial phase=RIPE
Constitutional phase=RI (Emb not needed if pan-sucept.)

*can't do the six month therapy without rifampin

17

Do you need DOT with intermittent therapy (2-3 times per week)?

yes

18

What drugs are only effective for NTM?

clarithro and azithro

19

What drugs are only effective for TB and not NTM?

INH and PZA

20

What drugs are effective for both TB and NTM?

Rif, Emb, FQ, AG (aminoglycosides)

21

Are the treatments the same in leprosy as in Tb?

no very different treatments !