Antituberculotic

Question 1

how is TB transmitted

Answer 1

expelled when a persion with infectious TB sneezes, speaks, sings or coughs

Question 2

what organism causes TB?

Answer 2

mycobacterium tuberculosis

Question 3

Name the 6 first line antituberculosis drugs

Answer 3

1. Isoniazid
2. Rifampin
3. Pyrazinamide
4. Ethambutol
5. Streptomycin
6. Rifabutin

Question 4

What drugs do you use in combination to treat an active TB infection

Answer 4

• Isoniazid
• Rifampin
• Pyrazinamide
• Ethambutol

*RIPE for treatment

Question 5

multi-drug resistant TB has become resistant to what Abx

Answer 5

• Isoniazid
• Rifampin

Question 6

extreme drug resistant TB has become resistant to which Abx

Answer 6

• Isoniazid
• Rifampin
• any Fluoroquinolone
• one injectible second line drug (capreomycin, kanamycin, amikacin)

Question 7

what is the recommended regimen of treatment for a new smear or culture positive case of TB

Answer 7

• take the following for 2 months
  
  • Isoniazid
  • Rifampin
  • Pyrazinamide
  • Ethambutol
• take the following for 4 months
  
  • Isoniazid
  • Rifampin

Question 8

Which abx are used in the treatment of latent TB disease

Answer 8

• Isoniazid

OR

• Rifampin

Question 9

what is the mechanism of action of Isoniazid? static or cidal

Answer 9

inhibits biosynthesis of mycolic acid (in cell wall)

• bacteriostatic
  
  • INH and Rifampin combo is bactericidal

Question 10

toxicity of Isoniazid

Answer 10

• Hepatitis
• Peripheral neuritis (slow acetylators)
• Hemolysis (in patients with 6GPD deficiencty)
• Lupus-like syndrome
• CNS stimulation

*weight benefits of prophylaxis vs risk of hepatitis, especially in patients 35 years or older

Question 11

route of administration of Isoniazid

Answer 11

oral

Question 12

metabolism of Isoniazid

Answer 12

• via acetylation (liver)
  
  • some people are “rapid” or “slow” metabolizers

Question 13

what is the MOA of Rifampin

Answer 13

inhibits DNA dependent RNA polymerase

Question 14

which antiTB drug is effective against leprosy

Answer 14

Rifampin

Question 15

spectrum of coverage of Rifampin

Answer 15

most G+ and some G-

Question 16

toxicities of Rifampin

Answer 16

1. Hepatic enzyme induction- potent inducer of cytochrome P450
2. harmless orange color to urine, sweat, tears, and contact lenses
3. decreases effectiveness of birth control

Question 17

Rifampin is not recommended for which patient population

Answer 17

HIV treated individuals

Question 18

MOA of Ethambutol? static or cidal

Answer 18

• inhibits arabinosyl transferases (involved in synthesis of arabinogalactan in the cell wall)
• bacteriostatic

Question 19

important distribution of Ethambutol

Answer 19

gets into the CNS

Question 20

toxicities of Ethambutol

Answer 20

• decrease of visual acuity
• loss of green-red perception (usually reversible upon discontinuation of drug)
  
  • not recommended in children below age 13 yo

Question 21

Inside what structure are mycobacterium tuberculosis in the body

Answer 21

• facultative intracellular parasite
• usually of macrophages

Question 22

when does Pyrazinamide become active?

Answer 22

active at acidic pH - optimal for Mtb within macrophages

Question 23

Pyrazinamide has the greatest activity against what stage of Mtb

Answer 23

dormant organisms

Question 24

toxicities of Pyrazinamide

Answer 24

hepatic dysfunction

Question 25

MOA of streptomycin? static or cidal

Answer 25

* protein synthesis inhibitor (30S ribosome) * bactericidal

Question 26

toxicities of Streptomycin

Answer 26

* otoxicity * nephrotoxicity

Question 27

MOA of Rifabutin

Answer 27

inhibits DNA dependent RNA polymerase

Question 28

When is Rifabutin used

Answer 28

* REPLACES Rigampin in **HIV-TB** co-infected individuals to avoid drug reactions * less potent inducer of P450 enzymes

Question 29

List the second line antiTB agents (lower potentcy and/or greater toxicity)

Answer 29

* para-aminosalicylic * ethionamide * capreomycin * amikacin * fluoroquinolones

Question 30

Mycobacterium avium complex (MAC) involves which two bacteria

Answer 30

* M. avium * M. intracellulare

Question 31

treatment of Mycobacterium avium complex (MAC)

Answer 31

antimicrobials for 12 months 1. either clarithromycin or azithromycin 1. I.V. amikacin if resistant to clarithromycin 2. ethambutol 3. Rifabutin, Rifampin, Or Ciprofloxacin

Question 32

Treatment of mycobacterium leprae in PB leprosy patients: 1-5 patches

Answer 32

* treat with the following for 6 months * Rifampin * Dapsone

Question 33

Treatment of mycobacterium leprae in MB leprosy patients: \> 5 patches

Answer 33

* treat with the following for 6-12 months * Rifampin * Dapsone

Question 34

MOA of Dapsone (the most widely used and least expensive drug)

Answer 34

similar to sulfonamides * **PABA antagonist**

Question 35

route of administration of Dapsone

Answer 35

oral

Question 36

toxicities of Dapsone

Answer 36

**nasal obstruction**: improves in 3-6 months

Question 37

Patients with leprosy can develop erythema nodosum leprosum (ENT). What drug would you add to the treatment regimen for moderate to severe ENL?

Answer 37

Thalidomide

Question 38

Thalidomide has orphan drug status for which conditions

Answer 38

* lepromatous leprosy * treatment of mycobacterium infections

Question 39

toxicities of Thalidomide

Answer 39

teratogenic \*should not be given at any time during pregnanct