Antituberculotics

Question 1

what are the first line antiTB drugs?

Answer 1

isoniazid
rifampin
pyrazinamide
ethambutol
streptomycin
rifabutin

Question 2

What is the first line combination treatment for active TB?

Answer 2

INH, Rif, EMB, PZA

Question 3

What is the course of treatment for latent TB?

Answer 3

either…

INH + RPT q once weekly for 3 months

OR

RIF q daily for 4 months

OR

INH q daily or twice weekly for 6-9 months

Question 4

what does INH inhibit?

Answer 4

mycolic acid synthesis

Question 5

when INH is given alone, is it static or cidal?

Answer 5

static

Question 6

combination with what drug makes INH cidal?

Answer 6

rifampin

Question 7

When considering prophylactic therapy, INH associated hepatitis should be considered especially in patients above what age?

Answer 7

> 35

Question 8

Describe the metabolism of INH

Answer 8

metabolism in the liver via acetylation

Question 9

What are five major toxicities of INH?

Answer 9

hepatitis, peripheral neuritis, hemolysis, lupus like syndrome, CNS stimulation

Question 10

who should you consider for INH induced hepatitis?

Answer 10

older persons, fast acetylators

Question 11

who should you consider for peripheral neuritis when administering INH?

Answer 11

slow acetylators

Question 12

who should you consider for risk of hemolysis when adminstering INH?

Answer 12

G6PD deficiency

Question 13

what is the mechanism of action for rifampin?

Answer 13

inhibition of DNA dependent RNA polymerase

Question 14

what confers resistance to rifampin?

Answer 14

rpoB mutation

Question 15

which tuberculo-static drug comes closest to the activity of INH?

Answer 15

rifampin

Question 16

Why is rifampin not recommended for HIV treated individuals?

Answer 16

CYP450 induction can cause drug interactions w/ HAART

Question 17

A patient takes oral contraceptives and rifampin. what should you caution them on?

Answer 17

rifampin decreases birth control effectiveness via CYP450 induction

Question 18

how does ethambutol work?

Answer 18

inhibition of arabinosyl transferases

Question 19

is ethambutol cidal or static?

Answer 19

static

Question 20

is ethambutol given for prophylaxis of TB?

Answer 20

no

Question 21

Where is ethambutol well absorbed?

Answer 21

most tissues, and into the CNS

Question 22

do you need to adjust the dose of ethambutol in renal failure?

Answer 22

yes

Question 23

Describe the major adverse effect of ethambutol…

Answer 23

decreased visual acuity, loss of red/green perception

reversible upon discontinuation

Question 24

is ethambutol recommended for children under 13?

Answer 24

no due to adverse effect on vision. This is NOT a contraindication. monitor closely

Question 25

at what pH is pyrazinamide active?

Answer 25

acidic pH

Question 26

do you change dosage if your patient is showing signs of fast or slow acetylation of INH?

Answer 26

No

Question 27

what do you give in addition to INH to prevent peripheral neuritis?

Answer 27

Pyridoxine

Question 28

does rifampin cause hepatotoxicity?

Answer 28

no

Question 29

does pyrazinamide reach the meninges?

Answer 29

yes!

Question 30

If a patient w/ active TB is experiencing hepatic dysfunction, which drug do you take them off of first? INH or PZA?

Answer 30

PZA and replace with a second line drug

Question 31

When is streptomycin used for TB?

Answer 31

as a second line in MDR, XDR

Question 32

What differentiates rifabutin from rifampin?

Answer 32

less potent induction of P450s

Question 33

when do you use rifabutin instead of rifampin?

Answer 33

in HIV-TB co-infected individuals

Question 34

when do you use rifapentine?

Answer 34

preferred regimine + INH for latent TB

Question 35

describe the drug interactions with rifapentine...

Answer 35

moderate P450 induction

Question 36

what 2 bacteria make up the mycobacterium avium complex?

Answer 36

m. avium and m. intracellulare

Question 37

how is MAC treated and for how long?

Answer 37

12 months, clarithromycin/azithro + ethambutol + rifabutin/rifampin/cipro

Question 38

why does m. leprae require multidrug therapy?

Answer 38

monotherapy will always result in resistance to that drug

Question 39

what constitutes PB leprosy?

Answer 39

1-5 patches

Question 40

how do you treat PB leprosy?

Answer 40

rifampin + dapsone for 6 mo

Question 41

what constitutes MB leprosy?

Answer 41

> 5 patches

Question 42

how do you treat MB leprosy?

Answer 42

rifampin + dapsone for 6-12 months

Question 43

what is the mechanism of dapsone?

Answer 43

PABA antagonist, similar to sulfa

Question 44

describe the rate of excretion of dapsone...

Answer 44

slow

Question 45

what is the most serious side effect of dapsone?

Answer 45

serious nasal obstruction interfering with patient compliance Dapsone? DatNoseDoe!

Question 46

why is thalidominde used in treatment of leprosy?

Answer 46

it is the DOC for moderate to severe erythema nodosum leprosum