TB

Question 1

What is the WHO Rx success target for TB

Answer 1

85%

Question 2

Two Phases of TB treatment

Answer 2

Intensive phase

Continuation phase

Question 3

Objectives of each phase of TB RX

Answer 3

Intensive - Clinical improvement and negative sputum

Continuation - Prevent relapse and sterilisation

Question 4

Name 3 metabolic populations of TB

Answer 4

Rapid multipliers
Slow multipliers
Sporadic multipliers

Question 5

Which TB drugs target each metabolic population of bacilli

Answer 5

Rapid - INH>RIF>EMB

Slow - PZA>RIF>INH

Sporadic - RIF>INH

Question 6

Difference between TB and gram + cell wall

Answer 6

TB has Capsule + Mycolic acid + Arabinogalactan layers. Over and above the Peptidoglycan and Cell membrane layers of gram +

Question 7

MOA of INH

Answer 7

Inhibits mycolic acid synthesis

Question 8

AEs of INH

Answer 8

Peripheral neuropathy (vit B6)
Hepatitis

Question 9

PK of INH

Answer 9

Prodrug (activated by cKatG and mycobacterial catalase peroxidase)

Question 10

How is INH metabolised

Answer 10

Acetylation (genetically determined)

Question 11

MOA of Rif

Answer 11

Inhibits RNA synthesis

Bind subunit of bacterial DNA-dependent RNA polymerase

Question 12

Most common AEs of Rif

Answer 12

Rash
Fever
Nausea
Vomiting

Question 13

Less common AEs of Rif

Answer 13

Hepatitis

Hypersensitivty

Question 14

PK of Rif

Answer 14

Absorption decreased with food.
Autoinduction.
Excreted into bile.

Question 15

Main challenges of dual HIV/TB therapy

Answer 15

1. Interactions
2. Toxicity
3. IRIS
4. Pill burden

Question 16

Options for lop/rit dose when given with rif

Answer 16

Double dose.
or
Add 300mg rit to the 400mg lop dose.

Question 17

MOA of pyrazinamide

Answer 17

1. Inhibit fatty acid synthase (inhib mycolic acid synthesis)
2. Reduces intracellular pH
3. Disrupt membrane transport.

Question 18

AEs of pyrazinamide

Answer 18

Hepatiis
Gout
Hypersensitivity

Question 19

PK of pyrazinamide

Answer 19

Good tissue penetration

Active at low pH

Question 20

MOA of ethambutol

Answer 20

Inhibits arabinogalactan synthesis

Question 21

AEs of ethambutol

Answer 21

Retrobulbar neuritis (dose dependent)
Hyperuricaemia (gout)

Question 22

PK of ethambutol

Answer 22

Poor CNS penetration
Renal elimination (adjust in KD)

Question 23

3 hepatotoxic TB drugs

Answer 23

PZA, INH, RIF

Question 24

Risk factors for TB dili

Answer 24

1. Age
2. Female
3. Malnutrition
4. HIV
5. Chronic Hep B/C

Question 25

When TB dili usually occur?

Question 26

Definition of TB dili

Answer 26

``` ALT >120 and symptomatic or ALT>200 and assymptomatic or Total bilirubin >40umol/l ```

Question 27

What can TB dili be confused with

Answer 27

/.Asymptomatic transaminitis (ALT

Question 28

Define MDR TB

Answer 28

Resistance to Rif and INH

Question 29

Define XDR TB

Answer 29

Resistance to INH, Rif and NB second line drugs (Quinolones and injectables)

Question 30

Treatment of MDR TB intensive phase

Answer 30

``` [6months - or until culture conversion] Kanamycin Moxifloxacin Ethionamide Terizidone Pyrazinamide ```

Question 31

Treatment of MDR TB continuation phase

Answer 31

``` [18 months] Moxifloxacin Ethionamide Terizidone Pyrazinamide ```

Question 32

If hearing loss, renal insufficiency or peripheral neuropathy in MDR Rx, which drug should you consider

Answer 32

Capreomycin

Question 33

egs of Flouroqinolones

Answer 33

Ofloxacin Levofloxacin Moxifloxacin

Question 34

egs of Aminoglycasides

Answer 34

Streptamycin Amikacin Kanamicin