Respo Module - TB Drugs

Question 1

First line of agents for TB ?

Answer 1

Isoniazid, rifampin , ethambutol , pyrazinamide for 2 months

• isoniazid and rifampin for 4 months more

Question 2

Drugs regime for px with past hx of TB or multidrug resistant tb

Answer 2

Isoniazid+rifampin+ethambutol+pyrazinamide (1st line of drug choice)

1st drug + aminoglycoside / injectable capreomycin / fluoroquinolone / 2nd line TB drug

Question 3

MOA of isoniazid

Answer 3

Inhibit enzyme that synthesize mycolic acid

Question 4

Name the enzymes that synthesize mycolic acid

Answer 4

• enoyl acyl carrier protein reductase (InhA)

- b-ketoacyl ACP synthase

Question 5

What activates isoniazid?

Answer 5

Isoniazid is prodrug that is activated by mycobacterial catalase peroxidase (KatG)

Question 6

Isoniazid is bacteriostatic in

Answer 6

Stationary phase

Question 7

In rapidly dividing organism isoniazid is

Answer 7

Bacteriocidal

Question 8

ROA of isoniazid

Answer 8

Oral administration

Question 9

Adverse effects of isoniazid

Answer 9

Peripheral neuritis 
Hepatitis 
Mental abnormalities
Optic neuritis
Hypersensitivity = rash and fever
Idiosyncratic hepatotoxicity

Question 10

How isoniazid is inactivated before excretion

Answer 10

N acetylation , hydrolysis

Question 11

-ve drug interactions of isoniazid

Answer 11

Phenytoin , carbamazepine, and benzodiazepines.

Question 12

____ has broader antimicrobial activity

Answer 12

Rifampin

Question 13

Mechanism of action of rifampin

Answer 13

Blocks transcription by interacting with the the beta subunit of bacterial but not human DNA dependent RNA polymerase

Question 14

Rifamycin family

Answer 14

Rifapentin
Rifabutin
Rifampin

Question 15

Rifampin is bactericidal?

Answer 15

True

Question 16

Rifampin is also given in treatment of?

Answer 16

Meningitis caused by Meningococi and haemophilus influenza.

Question 17

ROA of rifampin

Answer 17

Oral administration

Question 18

Adverse effects of rifampin

Answer 18

• nausea , vomiting , rash
• hepatitis
• fever , chills , myalgia (when given intermittently or daily dosage of 1.2gm or greater)
• acute renal failure
• hemolytic anemia
• shock

Question 19

Name of drug that is given to px infected with tb and hiv

Answer 19

Rifabutin

Question 20

Adverse effect of rifabutin

Answer 20

Neutropenia
Hyperpigmentation
Uveitis
Nausea , vomiting , rash
Hepatitis

Question 21

MOA of ethambutol

Answer 21

Ethambutol inhibits mycobacterial arabinosyl transferases,

Question 22

mycobacterial arabinosyl is encoded by

Answer 22

embCAB operon

Question 23

Arabinosyl transferases are involved in

Answer 23

the polymerization reaction of arabinoglycan, component of mycobacterial cell wall

Question 24

roa of ethambutol ? absorption from gut ?

Answer 24

oral adminsitration , well absorbed from the gut.

Question 25

excretion of ethambutol

Answer 25

by kidney , glomerual filtration and tubular secretion.

Question 26

adverse effect of ethambutol

Answer 26

gout exacerbate retrobulbar/ optic neuritis neuritis, resulting in loss of visual acuity and red-green color blindness Hypersensitivity is rare.

Question 27

ethambutol is contraindicated in ?

Answer 27

children too young to permit assessment of visual acuity and red-green color discrimination.

Question 28

higher doses of ethambutol is given in ?

Answer 28

tuberculosis meningitis

Question 29

body excretion color changes in ?

Answer 29

rifampin adminstration

Question 30

Pyrazinamide (PZA) is ?

Answer 30

a relative of nicotinamide, and it is used only for treatment of tuberculosis

Question 31

prodrug form / active form of PZA

Answer 31

pyrazinoic acid

Question 32

PZA is converted into its active form by

Answer 32

mycobacterial pyrazinamidase

Question 33

action of pyrazinoic acid

Answer 33

disrupts mycobacterial cell membrane metabolism and transport functions.

Question 34

roa and absorption of PZA

Answer 34

oral , well absorbed from gut

Question 35

distribution of PZA

Answer 35

widely distributed in body tissues, including inflamed meninges.

Question 36

aminoglycoside

Answer 36

streptomycin

Question 37

2nd line drugs for TB

Answer 37

Aminoglycoside, macrolide , fluoroquinolone , caperomycin , cycloserine , ethianoamide , aminosalicyic acid.

Question 38

drug for leprosy

Answer 38

clofazimine , dapsone , rifampin

Question 39

roa of streptomycin

Answer 39

Streptomycin sulfate is used when an injectable drug

Question 40

adverse effect of streptomycin

Answer 40

ototoxic and nephrotoxic. Vertigo and hearing loss are the most common adverse effects and may be permanent.

Question 41

MOA of ethanoamide

Answer 41

chemically related to isoniazid and similarly blocks the synthesis of mycolic acids.

Question 42

adverse effect of ethanoamide

Answer 42

hepatotoxic

Question 43

roa of capreomycin

Answer 43

intramuscularly

Question 44

moa of capreomycin

Answer 44

peptide protein synthesis inhibitor antibiotic

Question 45

capreomycin adverse effect

Answer 45

nephrotoxic and ototoxic. Tinnitus, deafness, and vestibular disturbances occur. The injection causes significant local pain, and sterile abscesses may develop.

Question 46

moa of cycloserine

Answer 46

inhibits cell wall synthesis,

Question 47

cycloserine adverse effects

Answer 47

serious toxic effects are peripheral neuropathy and central nervous system dysfunction, including depression and psychoses.

Question 48

Aminosalicylic acid moa

Answer 48

folate synthesis antagonist that is active almost exclusively against M tuberculosis

Question 49

aminosalicylic acid adverse effect

Answer 49

Peptic ulceration and hemorrhage may occur. Hypersensitivity reactions manifested by fever, joint pains, skin rashes, hepatosplenomegaly, hepatitis, adenopathy, and granulocytopenia often occur after 3–8 weeks of PAS therapy, making it necessary to stop administration temporarily or permanently

Question 50

WHO recommendation about fluoroquinolone usage

Answer 50

World Health Organization recommends using a later generation fluoroquinolone such as moxifloxacin or levofloxacin.

Question 51

adverse effect of linezolid

Answer 51

bone marrow suppression and irreversible peripheral and optic neuropathy, (prolonged courses of therapy that are necessary for treatment of tuberculosis)

Question 52

linezolid is used

Answer 52

in combo with 2nd or 3rd line of drug , treatment of px with multi-drug resistant strain