Dr. Jakeman

Question 1

How is TB transmitted?

Answer 1

-Via droplet nuclei

Question 2

Signs and symptoms of Latent TB Infection

Answer 2

• Live in the body but dormant
• Positive TST and IGRA
• Normal chest Xray
• Negative sputum/cultures
• Pts are not contagious in this phase

Question 3

Diagnosis of primary TB

Answer 3

• Physical exam
• Positive TST and IGRA
• Abnormal chest Xray
• Positive sputum and culture smear

Question 4

Treatment regimens for LTBI

Answer 4

1) Isoniazid 300mg daily for 9 months
2) Isoniazid 900mg plus Rifapentine 900mg once weekly for 3 months
3) Rifampin 600mg daily for 4 months

Question 5

Advantages of Isoniazid and Rifapentine regimen

Answer 5

• Higher completion rates
• Shorter duration
• Less hepatotoxicity
• Given once weekly

Question 6

RIPE Treatment for TB

Answer 6

• Rifampin
• Isoniazid
• Pyrazinamide
• Ethambutol

Question 7

Dosing for Rifampin

Answer 7

• 10mg/kg/day
• Based on TBW
• Max dose is 600mg/day

Question 8

Dosing for Isoniazid

Answer 8

• 5mg/kg/day
• Based on TBW
• Max dose is 300mg/day

Question 9

Dosing for Pyrazinamide

Answer 9

• Use IBW
• 40 to 55kg = 1g
• 56 to 75kg = 1.5g
• 76 to 90kg = 2g
• If CrCl < 30ml/min dose 3x/week

Question 10

Dosing for Ethambutol

Answer 10

• Use IBW
• 40 to 55kg = 800mg
• 56 to 75kg = 1200mg
• 76 to 90kg = 1600mg
• If CrCl < 30ml/min dose 3x/week

Question 11

Length of initial phase vs continuation phase

Answer 11

• Initial phase = 2mo

- Continuation phase = 4-7mo

Question 12

Drug-Drug interactions

Answer 12

• Always run an interaction check
• Rifamycins are common inducers (decrease other drugs to sub-therapeutic levels)
• Isoniazid is an inhibitor (Increasing other drugs to toxic levels)

Question 13

Why does mycobacterial resistance occur?

Answer 13

• Poor prescribing practices
• Poor treatment programs
• Drug PK/PD issues
• Poor infection control
• Drugs kill susceptible bugs and leave resistant ones

Question 14

Patients at risk for resistant TB

Answer 14

• Culture positive after 2 to 4mo of treatment
• Previously treated for TB
• In contact with pt with resistant TB

Question 15

MDR definition

Answer 15

• Resistant to isoniazid and rifampin

- The two best first line TB drugs

Question 16

XDR TB

Answer 16

• Resistant to the two best first line TB drugs
• Any fluoroquinolone
• And at least 1 of 3 injectable 2nd line TB drugs

Question 17

How to prevent resistance

Answer 17

• Multidrug therapy
• Promote medication adherence
• Monitor for intolerance or toxicities

Question 18

HIV and TB

Answer 18

• More likely to go from LTBI to active infection
• Use Rifabutin over rifambin
• Less drug interactions

Question 19

Liver disease and TB

Answer 19

• Use INH and RIF if possible
  1) No INH- Rifampin, ethambutol, and pyrazinamide x 6mo
  2) Avoid PZA- use INH, RIF, EMB x 9mo
• D/C ethambutol if PAN sensitive