Tuberculosis: Treatment and prevention 2

Question 1

Rifampicin is metabolized where? and causes what?

Answer 1

Metabolism in the liver-causes autoinduction and potent enzyme induces

Question 2

the elimination of rifampicin

Answer 2

Primary biliary faecal route

Question 3

Rifampicin causes drug interaction with which drugs?

Answer 3

Drug-interactions with drugs
metabolised in the liver
* Oral contraceptives & progestin
implants (replace with injectable
contraceptives)

Question 4

Rifampicin causes which colour of pigmentation to body fluids

Answer 4

Orange, red, brown

Question 5

Explain the distribution of Isoniazid

Answer 5

wide including the CSF

Question 6

where is isoniazid metabolised

Answer 6

Metabolism in the liver via acetylation (slow acetylators at greater risk of neurotoxicity)

Question 7

The excretion of isoniazide

Answer 7

Inactive metabolites of isoniazid excreted in the urine

Question 8

Neurotoxicity reversed by what?

Answer 8

Pyridoxine (B6)

Question 9

Drug interactions of izoniazid

Answer 9

Drugs metabolised in the liver (weak enzyme inhibitors)

Question 10

Caution of isoniazid in patient with what?

Answer 10

epilepsy

Question 11

Explain the distribution, metabolis and excretion of ethambutol

Answer 11

Pharmacokinetics
* Distribution: wide not in CSF
* Metabolism in the liver up to
15%
* Mainly unchanged in the urine

Question 12

Say the contra-indication and caution of ethambutol

Answer 12

• Contra-indications: optic neuritis
• Cautions: renal failure, in
  children under 8 years (visual
  symptoms difficult to assess),
  hyperuricaemia

Question 13

say one adverse effect of ethambutol

Answer 13

Ocular toxicity – patient selfmonitoring
(reading fine print),
monitor: colour discrimination
and visual field

Question 14

Distribution of pyrazainamide

Answer 14

wide including CSF

Question 15

In pyrazinamide, hepatotoxicity is what?

Answer 15

dose related

Question 16

explain the cause of hyperuricaemia in pyrazinamide

Answer 16

Hyperuricaemia (caused by
decreased uric acid clearance)
associated with arthralgia (may
precipitate gout)

Question 17

TB treatment otcomes
wanted vs unwanted
list them

Answer 17

Wanted
* Prevent TB transmission
* Cure with minimal problems
* Cure with chronic lung disease
Unwanted
* Transmission of TB
* MDR / XDR
* Death

Question 18

List the seven Drug resistant TB categories

Answer 18

• Mono-resistant TB
• Poly-resistant TB
• MDR-TB
• Rifampicin resistant-TB (RR-TB)
• Resistance to at least rifampicin
• Extensively drug-resistant TB (XDR-TB)
• Pre-XDR-TB

Question 19

Explain the MDR (multi DR)

Answer 19

MDR (multi DR)
* In vitro resistance to:
* Rifampicin
* Isoniazid
* With or without resistance to other
anti-TB drugs

Question 20

Explain the XDR (extensively DR)

Answer 20

• MDR TB
• +
• In vitro resistance to:
• Any fluoroquinolone
• AND
• Any injectable drug
• Extremely difficult and expensive to
  treat with a high mortality (90%) in
  HIV co-infected patients

Question 21

what are resistance test for Isoniazid resistance

Answer 21

Resistance tests:
* inhA mutation and
* katG mutation

Question 22

explain the test of izoniazid resistance

Answer 22

• inhA mutation only (use high dose INH: 10mg/kg/day)
• katG mutation (use ethionamide)
• Complete resistance (both)
• Do not use INH or ethionamide

Question 23

Differentiate the Drug-resistance TB treatment short regimens

Answer 23

Short regimen
Pre -2024 – old regimen being phased out:
* Short course:
* At least 6 drugs used for 9 months
2024 – new regimen being phased in:
* BPaL-L:
* At least 3 drugs used for 6 months

Question 24

explain the long regimen in drug-resistant TB treatment regimens

Answer 24

Long regimen
* 18 months
* Complicated EPTB / extensive
disease on CXR
* Children < 6 years
* Hx of previous treatment with 2nd
line drugs for more than 1 month
* Contact with XDR / Pre-XDR
* Both INH mutations

Question 25

differentiate between short course and new short cause- BPaL-L under drug resistant TB treatment short regimens

Answer 25

Short course
* 9 months
* Adults, pregnant women and
children ≥6 years (≥ 16kg)
New short course – BPaL-L
* 6 months

Question 26

List the drugs for Drug-resistant TB treatment: BPaL-L (6 months)

Answer 26

-The 6-month BPaL-L regimen;
* Bedaquiline,
* Pretomanid,
* Linezolid (600 mg)
* With or without levofloxacin (if sensitive)

Question 27

List drugs for drug-resistant TB treatment: long course

Answer 27

Core drugs:
* Bedaquiline,
* Linezolid
* Levofloxacin (substitute if fluoroquinolone resistance)
* Clofazimine
* Terizidone
* Co-administer pyridoxine (50mg for adults, 25 mg to children) to
prevent peripheral neuropathy due to terizidone

Question 28

List drugs for children for drug-resistant TB treatment:long course

Answer 28

Children:
* Bedaquiline ≥6 years is safe for use
Substitute bedaquiline for:
* Delamanid (3 to 6 years)
* Para-aminobenzoic acid (less than (<)3 years)