Tuberculosis pharmacology/therapeutics Flashcards Preview

PT3 ID 1 (HIV) > Tuberculosis pharmacology/therapeutics > Flashcards

Flashcards in Tuberculosis pharmacology/therapeutics Deck (48):
1

how is tuberculosis spread

through the air in droplets

2

extrapulmonary tuberculosis

-tuberculosis infection that spreads beyond the lungs
-makes up about 15% of cases

3

mycobacterium tuberculosis features

-gm+
-mycolic acids make up outer membrane
-slow growing
-resides in macrophages
-rapidly develop resistance

4

what do drugs target in TB

cell wall/FAS

5

symptoms of active TB

-productive prolonged cough
-coughing up blood
-chest pain
-fever
-night sweats
-easily fatigued
-unexplained weight loss

6

symptoms of latent TB

-no obvious symptoms
-granulomatous lesions in lung

7

positive TST(PPD) for HIV infected/immunocompromised

>5 mm

8

positive TST(PPD) for high risk or injection drug user

>10 mm

9

positive TST(PPD) for person with no risk factors

>15 mm

10

TB vaccine

BCG
lasts 10-20 years

11

drug susceptibility test

MODS assay using sputum samples grows faster than normal cultures

12

1st line regimen for active TB infection

2 months: rifampin, isoniazid, pyrazinamide, ethambutol

then 4 months of: rifampin, isoniazid

13

isoniazid moa

inhibits biosynthesis of mycolic acids by binding to NAD to prevent elongation

14

isoniazid ADME

-rapidly absorbed
-t1/2 depends on fast or slow acetylators (1-3 hours)
-inhibits hepatic enzymes

15

isoniazid adverse effects

-peripheral neuropathy due to interference with pyridoxine (B6) metabolism, can be averted by Vit B6 supplements
-rarely hepatitis
-inhibits hepatic enzymes

16

rifampin moa

binds to beta-subunit of bacterial DNA dependent RNA polymerase preventing synthesis

17

rifampin ADME

-lipid-soluble
-t1/2 of 2-3 hours
-induces and inhibits 3A4

18

rifampin adverse effects

-reddish coloration of urine, tears, saliva
-flu like symptoms
-thrombocytopenia

19

rifampin drug interactions

-oral anticoagulants
-oral contraceptives
-methadone
*will need dosage changes*

20

ethambutol moa

inhibits cell wall by preventing mycolic acids from attaching to arabinogalactan

21

ethambutol ADME

t1/2 = 3-4

22

ethambutol adverse effects

optic neuritis that can lead to blindness if drug isn't stopped

23

pyrazinamide moa

binds ribosomal protein
*only in pH*

24

pyrazinamide ADME

half life of 10 hours

25

pyrazinamide adverse effects

-GI intolerance
-occasionally gout

26

multidrug resistant TB treatment

at least 4 effective drugs for 18-24 months

27

risk that a person will have active TB in life time

10%

28

how does PPD test work

tuberculin is injected and if the body has been exposed to TB the T cells are sensitized and mount a response

29

recent converter

based on reading 2 years ago:
for <35 PPD increases by more than 10 mm
for >35 PPD increases by >15 mm

30

who is at greatest risk of converting latent TB to active

-weak immune systems
-starting steroid use

31

isoniazid prophylactic dose in none HIV

300 mg qd for 9 months

32

isoniazid prophylactic dose in HIV patients

300 mg qd for at least 12 months

33

rifampin prophylactc dose

600 mg qd for 4 months

34

what needs to be added to regimen in isoniazid based regimens for those at risk for neuropathy

pyridoxine (B6) 25 mg qd

35

workup for active TB

-signs and symptoms
-chest xray
-3 morning sputum samples
-PPD

36

stain to see mycobacteria

acid fast bacilli stain of sputum, not culture

37

treatment regimen for active TB initial phase

always 4 drugs for 8 weeks with pyridoxine

38

if after initial treatment phase cavitation OR AFB positive

begin continuation phase as isoniazid and rifampin for 4 months

39

if after initial treatment phase cavitation AND culture positive

isoniazid and rifampin for 7 months

40

overall active TB treatment timing

-initial phase 2 months
-continuation phase 4-7 months
total = 6-9 months

41

those at highest risk for neuropathy when taking isoniazid

DM
alcoholics
malnourished
HIV
pregnancy
seizures

42

isoniazid INH

-inhibit hepatic enzyme
-neuropathy
-hepatitis

43

drug that can cause thrombocytopenia

rifampin

44

what to do if hepatitis occurs

-stop isoniazid, rifampin, pyrazinamide
-regimen with ethambutol and other abx
-restart 1st lines when AST <2x upper limit of normal

45

2nd line agents

kanamycin
viomycin
capreomycin
amikacin
streptomycin
levofloxacin
cycloserine
ethionamide

46

former 1st line agent that is now 2nd line

streptomycin due to ototoxicity

47

what to do if resistant bugs are resistant to a drug

replace with at least 2 drugs it is susceptible to

48

how to deal with GI distress

-take with food or change dosing hour
-DO NOT split dosing (cutting tablets)