Anti-Mycobacterials

Question 1

How do you monitor a patient for elimination of TB?

Answer 1

• serial sputum specimens with smear and culture negative

- chest X-ray

Question 2

Principles of TB treatment

Answer 2

• Multi drug therapy
• Focus on increasing adherence and dosage completion
• Adequate duration of therapy

Question 3

Clinical use of Isoniazid Hal (INH)

Answer 3

• First line drug for active pulmonary TB

- used in combination, usually with at least two other active drugs

Question 4

Resistance mechanisms to Isoniazid HCl

Answer 4

• Mutations in katG gene –>/ catalase peroxidase –> INH activation
• Mutation in inhA gene –>/ cell wall (mycelia acid) synthesis

Question 5

Does INH spread to CNS?

Answer 5

yes

Question 6

Clinical use of Rifampin

Answer 6

Only used alone in latent TB or meningitis prophylaxis because of rapid development of resistance

Question 7

Does Rifampin spread to CNS?

Answer 7

yes

Question 8

Toxicity of Rifampin

Answer 8

• red discoloration of body fluids
• influenza syndrome (more common with intermittent dosing)
• thrombocytopenia

Question 9

Drug Interactions of Rifampin

Answer 9

-interactions with over 100 drugs through induction of microsomal enzymes

Question 10

Clinical use of Ethambutol

Answer 10

• First line of TB therapy

- Helper drug that inhibits resistance to other drugs

Question 11

Toxicity of Ethambutol

Answer 11

• Optic neuritis symptoms: blurred vision, central scotomata, red-green color vision loss, dose-related
• peripheral neuropathy

Question 12

Clinical use of Pyrazinamide

Answer 12

• First line TB drug for first TWO MONTHS of therapy

- always used in combination

Question 13

Clinical use of streptomycin

Answer 13

second line TB drug

Question 14

Primary TB resistance

Answer 14

acquired at infection

Question 15

Secondary TB resistance

Answer 15

developed during therapy

Question 16

Describe resistance to two drugs

Answer 16

Risk of evolution of resistance to two drugs is the product of the risk of the development of each drug

Question 17

What is MDR-TB?

Answer 17

resistance to both INH and rifampin

Question 18

Consequence of rifampin resistance

Answer 18

eliminates short course therapy (6 months)

-requires therapy for at least 18-24 months

Question 19

What is the 4 drug regimen for initial phase of TB treatment?

Answer 19

RIPE

• Rifampin
• INH (Isoniazid HCl)
• Pyrazinamide
• Ethambutol

Question 20

What is the continuation phase of TB treatment?

Answer 20

RI

• Rifampin
• Isoniazid HCl

Question 21

Requirements for intermittent therapy

Answer 21

Intermittent (2-3 times per week) therapy only with Direct Observation Therapy

Question 22

6 month therapy has high success rate if:

Answer 22

• Adherence is high
• Sputum cultures convert by 2 months
• No major cavitary lung disease

Question 23

What is extremely drug resistant TB?

Answer 23

Resistance to INH, rifampin, a fluoroquinolone, and 1 injectable

Question 24

Fundamental strategy to TB treatment

Answer 24

• use at least two drugs to which patient’s TB strain is susceptible
• use only drugs that have never been used before

Question 25

Treatment of Latent TB

Answer 25

• INH mono therapy for 9 months
• Rifampin for 4 months
• INH and Rifapentene for 3 months once weekly, Direct observed therapy

Question 26

Treatment of NTM infections vs. TB regimens

Answer 26

Some antibiotics are active against both TB and NTM, whereas others are uniquely active against one or the other type of mycobacteria

Question 27

Treatment of Leprosy vs. TB regimens

Answer 27

Very different from TB treatment