Anti TB drugs

Question 1

Frontline TB drugs

Answer 1

• Isoniazid
• Rifampin
• Ethambutol
• Pyrazinamide

Question 2

Anti-TB drugs should be discontinued if what?

Answer 2

serum bilirubin is > or equal to 3 mg/dL

or

Serum transaminases are more than 5 times the upper limit of normal

Question 3

Goals of TB treatment

Answer 3

• eradicate M. Tuberculosis infection
• Prevent emergence of drug resistance
• Prevent relapse of infection

Question 4

Describe the therapy necessary got TB to achieve the goals

Answer 4

prolong multi drug regimen

Question 5

How long do you use all 4 first line TB drugs and what phase is this

Answer 5

8 weeks . . intensive phase

Question 6

What drugs do you use after 8 weeks? and what phase is this

Answer 6

Isoniazid and Rifampin . . . continuation phase

Question 7

What is the purpose for the use of 4 drugs?

Answer 7

resistance

Question 8

Route of administration for TB drugs

Answer 8

oral

Question 9

What PARENTERAL drug is sometimes used in hospital setting in patients who cannot tolerate P.O. drugs

Answer 9

Streptomycin (aminoglycoside)

Question 10

Isoniazid is bactericidal in what type of TB?

Answer 10

growing

Question 11

isoniazid works by disrupting what?

Answer 11

mycolic acid synthesis

Question 12

What mycobacterial enzyme converts isoniazid into its active metabolite?

this then blocks what?

Answer 12

Catalase peroxidase (KatG)

InhA and KasA

Question 13

Isoniazid resistance mechanisms

Answer 13

• depletion of katG

- overexpression/mutation of InhA and KasA

Question 14

What ethnicity are the fast acetylators of isoniazid

Answer 14

Asians

Question 15

What ethnicity are “slow acetylators” of isoniazid?

Answer 15

• caucasians
• Blacks
• Hispanics

Question 16

What hepatic enzyme acetylates isoniazid

Answer 16

NAT

Question 17

2 Major adverse reactions to Isoniazid?

Answer 17

Hepatic

• Elevated liver enzymes
• Jaundice
• Hepatitis

Neurologic

• Peripheral neuritis (paresthesias)
• convulsions

Question 18

Which acetylators get increased exposure to N-acetylhydrazine causing more hepatotoxicity

Answer 18

slow ones

Question 19

Isoniazid reacts convalently with ______ which depletes pools of what neurotransmitter leading the neuropathy

Answer 19

pyridoxal-5-phosphate

GABA

Question 20

What does Rifampin inhibit?

Answer 20

DNA dependent RNA polymerase

Question 21

Describe the characteristic of Rifampin effectiveness?

Answer 21

bacericidal even on SLOW GROWING bacteria

Question 22

Which Tb drug has high intracellular penetration?

Answer 22

Rifampin

Question 23

What TB drug stains things red/orange like urine, sweat, and contact lenses

Answer 23

Rifampin

Question 24

Which TB drug is a strong inducer of CYP enzymes and can increase clearance of oral contraceptives and can cause unplanned pregnancy/

Answer 24

Rifampin

Question 25

What drug would you substitute for Rifampin in HIV/AIDS patients

Answer 25

Rifabutin

Question 26

Which drug is narrow spectrum and is used for mycobacteria tuberculosis at ACIDIC pH

Answer 26

Pyrazinamide (PZA)

Question 27

What enzyme does Ethambutol inhibit?

Answer 27

Arabinosyl transferases and cell wall synthesis

Question 28

Adverse effects of ethambutol?

Answer 28

- Visual (optic neuritis, color disturbance) | - Renal (gout)

Question 29

What TB drug blocks tubular secretion of urate leading to hyperuricemia and urate crystals

Answer 29

Ethambutol

Question 30

Treatment for Latent TB

Answer 30

isoniazid daily for 9 months

Question 31

What 3 drugs for TB are considered safe for pregnancy in the USA

Answer 31

- isoniazid - Rifampin - ethambutol

Question 32

What is the leading killer of people who are HIV infected?

Answer 32

TB

Question 33

How do you go about treating a patient with TB and HIV

Answer 33

- initiate TB treatment first, then HIV - Avoid weekly INH-rifapentine - Avoid twice weekly INH-rifampin if CD4 count <100

Question 34

What 2 drugs is multi drug resistant TB resistant to?

Answer 34

isoniazid and rifampin

Question 35

What are the second line drugs that can be used to treat MDR-TB

Answer 35

Fluoroquinolones - moxifloxacin and levofloxacin Injectables - Amikacin, kanamycin, capreomycin, streptomycin Add on or core 2nd line - Ethionamide, p-aminosalicyclic acid (PAS), cycloserine

Question 36

MOA of bedaquiline

Answer 36

inhibits mycobacterial ATP synthase