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Pharmacology (5th year) > TB > Flashcards

Flashcards in TB Deck (27):
1

1st line TB treatment

Intenstive 2 months
- Rif, INH, PZA, etham

Continuation phase 4 months
- RIf, INH

2

When do patients become sputum negative?

After 2 months

3

Role of INH

- NB in early therapy
- bactericidal
- rapidly reduces bacterial count
- active mainly against aerobic organisms in cavities

4

Role of Rif

- killing slow metabolisers
- sterilizing patient's sputum

5

Role of PZA

- active at low pH
- ideal for killing organisms inside causeous necrotic foci

6

MOA of INH and Etham

Inhibits cell wall synthesis

7

MOA of Rif

Inhibits RNA synthesis
- binds to the subunit of bacterial DNA-dependent RNA polymerase

8

MOA of PZA

- disrupts plasma membrane
- disrupts energy metabolism

9

Adverse effects of INH

- dose and duration related
- peripheral neuropathy
- hepatitis

10

Pharmacokinetics

Produg - activated by cKatG,
Penetrates tissues well
Genetically determined acetylation

11

Toxicity effects of rifampicin

- rash, fever, nausea, vomiting
- hepatitis
- hypersensitivity

12

Pharmacokinetics of RIF

- variable absorption (food decreases)
- excreted into bile
- autoinduction
- strong CYP inducer

13

Challenges of dual HIV/TB therapy

- Drug-drug interactions
- overlapping toxicity
- pill burden
- IRIS

14

Toxicity effects of PZA

- hepatitis
- gout
- hypersensitivity

15

Pharmacokinetics of PZA

- penetrates tissues well
- active at low pH

16

Toxicity effects of ehtambutol

- retrobulbar neuritis
- hyperuricaemia and gout

17

Pharmacokinetics of ethambutol

- poor CNS penetration
- renal elimination (adjust in renal disease)

18

3 potentially hepatotoxic 1st line drugs

- PZA
- INH
- Rif

19

Risk factors for hepatotoxicity with TB meds

- age
- female
- malnutrition
- HIV
- Chronic Hep B/C

20

When does DILI usually occur?

- within the first 3 months

21

Definition of DILI

- ALT >120 and symptomatic
- ALT >200 and asymptomatic
- Total BR <40

22

MDR definiton

Resistance to INH and RIF

23

XDR definition

Resistance to INH, RIF and important 2nd line drugs (quinolones, injectables)

24

MDR treatement regimen

5 drugs for 6 months
4 drugs for 18 months

25

MDR intensive phase drugs

- kanamycin
- moxifloxacin
- ethionamide
- terizidone
- pyrazinamide

26

MDR continuation phase drugs

- moxiflox
- ethionamide
- terizidone
- pyrazinamide

27

2nd vs 1st line TB drugs

- more toxic
- more expensive
- longer duration
- less successful