TB lesson

Question 1

why is drug therapy needed in TB

Answer 1

to provide rapid bacterial killing to prevent the mergence of drug resistance
to eliminate persistent tubercle bacilli to prevent relapse

Question 2

what are the ttt desired outcomes

Answer 2

• prevent spread ot tb (respiatory isolation)
• find out where tb has already spread (contact investigation)
• bring the pt to a status of normal weight and well being

Question 3

latent tb ttt

Answer 3

isoniazid 300 mg for 9 months
5-10mg/kg
6 months in alternative therapy

isoniazid higher doses 2x or 3x weekly for 6-9months to prevent peripheral neuropathy

rifampin 600mg for 4 months in
isoniazid resistance
isoniazid intolerance

Question 4

active TB ttt

Answer 4

drug susceptibility testing in all pt. and repeat if pt culture positive 8 wks after ttt

RIPE - for 2 months
followed by rifampin and isoniazid for 4 months

9-12 months in

• high risk of failure relapse
• cavitary lesions on initial chest radiograph
• positive smear after initial 2 months of ttt

cont w 6 months in

• pt not ttt with pyrazinamide at start of ttt
• HIV pt not on anti retroviral ttt during tb
• bone and joints (6-9 months)
• CNS involvement (12months)

intensive phase -daily dosing preffered
2x or 3x weekly intermittent in
- low risk of relapse, negative smear at start of ttt, non cavitary tb
- HIV -ve pt

continuation phase - daily dosing preffered
3x weekly if intermittent
1x weekly not recommended unless pt incompliant

Question 5

completion of ttt

Answer 5

depends on
duration of ttt
no. of doses administered

active TB : intensive phase 60 doses within 3 months
cont phase 4 months within 6 months

latent tb : isoniazid
intensive phase 270 doses 9 mo. within 12 mo.
continuation phase : 180 doses 6 mo within 9 months

Question 6

intolerance to isoniazid

Answer 6

RPE for 6 months
poorly tolerated prolonged use of pyrazinamide
Rifampin + ethambutol for 12 months with pyrazinamide during initial 2 months

Question 7

intolerance to rifampin

Answer 7

Isoniazid + ethambutol for 12 month w. pyrazinamide for initial 2 months
injectable agent for first 2-3 months - extensive disease and reduce duration to 12 mo

Question 8

intolerance to pyrazinamide
gout, hepatotoxicity
pregnancy

Answer 8

Isoniazid + rifampin for 9 months

supplemented by ethambutol till I+R susceptibility demonstrated

Question 9

No hepatotoxic drug

Answer 9

Ethambutol + (levofloxacin or moxifloxacin) and other 2nd line drugs

Question 10

ttt monitoring general

Answer 10

1. CBC,BUN, hep enzymes, bilirubin, serum uric acid level
2. sym of hepatotoxicity from drug therapy
3. sputum culture 2-4 wks initially/ monthly after sputum negative
4. chest radiograph at completion of therapy

Question 11

monitoring of drugs

isoniazid

Answer 11

isoniazid - peripheral neuropathy - vit B6
hepatotoxicity increased hep enzyme
lupus like syndrome
increased phenytoin levels

monitor
routine Hep enzyme
repeat if abnormal baseline, risk factor for hepatitis or adv drug reac sym

Question 12

monitoring of drugs

rifampin

Answer 12

1. hepatotoxicty
2. pruritis w or w/o rash
3. nausea anorexia abdominal pain
4. orange discolouration of sputum tears urine fluids
5. DI due to act of hep microsomal enzymes

monitor
drug interaction
baseline CBC, platelets H. enzymes
*repeat

Question 13

monitoring of drugs

pyrazinamide

Answer 13

1. hepatotoxicity
2. gout, hyperuricemia
3. NV, abd dscomfort
4. morbilliform rash transient

monitor
hep enzymes if existing liver disease or used w rifampin for ttt of tb
serum uric acid level indicator of compliance

Question 14

monitoring of drugs

ethambutol

Answer 14

vision acquity disturbance
red green colour blindness
rash

_ monthly colour and acuity vision check