Tuberculosis Meds Flashcards

1
Q

Mandel-Mantoux Test

A
  • TST aka PPD
  • must be read within 48-72 hours
  • immunosuppressed pts (HIV, transplant, prior tb)
    • 5+mm = positive
  • Immunocompetent pts but high risk
    • 10+ mm = positive
  • Anybody with no known risk
    • 15+ mm = positive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

2-step TST testing

A
  • if negative rxn = retest 1-3 weeks later
    • if positive = rxn = boosted due to TB infx that happened a while ago, may or may not treat LTBI
    • if negative = person most likely does NOT have TB infx
  • if positive rxn = f/u for + TST and evaluate for LTBI tx
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

IGRAs

A

interferon-gamma release assays → infected WBCs produce interferon-gamma (IFN-g)

  • used to detect TB via blood test
  • Quantiferon-TB Gold plus
    • measure IFN-g level in blood
  • T-spot
    • measure of # of IFN-g producing cells (spots) – WBC
  • Advantages:
    • unaffected by BCG vaccine or other non-TB mycobacteria
    • results <24 hours vs 3 days with TST (PPD)
  • Disadvantages:
    • samples need to be processed in 8-30hours when WBCs are still viable
    • sensitivity may lower in immunocompromised
    • limited data for kids <5 yo; recently exposed to TB; and healthcare workers
    • more expensive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Sputum Test and TB

A

AM sputum collections x 3 days

  • can be induced by using aerosolized hypertonic saline
  • sputum is then smeared on a slide and stained with an “acid-fast” procedure
  • results available in a few hours
  • postive result? → presumptive positive diagnosis of tb
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

LTBI

A

Latent TB Infection

  • TB is in the body but is encapsulated by immune system cells
  • no s/sxs of TB
  • Results:
    • TST/IGRA results = +
    • CXR = -
    • smear and cx = -
  • cannot spread to others
  • High Priority for tx:
    • HIV infected pts
    • fibrotic changes on CXR
    • organ transplant recipients
    • immunosuppressed pts
      • >15mg/day of prednisone for 1+ months
      • taking TNF-alpha antagonists
        • etanercept (Enbrel)
        • infliximab (Remicade)
        • adalimumab (Humira)
    • IV drug users
    • immigrants <5 yrs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mycobacterial Cell Wall

A

Two important layers:

  • mycolic acid layer more superficial
  • arabinogalactan layer is deep to the other layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Which TB drugs inhibit cell-wall synthesis

A

IPE:

Isoniazid

Pyrazinamide

Ethambutol

and TCA1 (and inhibits cofactor biosynthesis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Which TB drug inhibits RNA synthesis

A

Rifampin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which TB drug inhibits ATP synthase

A

bedaquiline (Sirturo)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Rifamycins

A
  • Rifampin (Rifadin)
    • SEs: nausea, anorexia
      • hepatotoxicity
      • discoloration of body fluids
    • DDI: 1A2, 2C9, 3A4 inducer
  • Rifabutin (Mycobutin)
    • SEs:
      • neutropenia, leukopenia, thrombocytopenia
      • uveitis
      • hepatotoxicity
      • flu-like sxs
      • discoloration of body fluids
    • DDI: less than rifampin, weak inducer
  • Rifapentine (Priftin)
    • SEs:
      • similar to rifampin
    • DDI:
      • similar to rifampin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Isoniazid

A
  • prodrug
  • SEs:
    • hepatitis → elevation of LFTs (liver function tests)
    • neuropathy→ Should give with Vitamin B6
    • lupus-like syndrome → swollen, painful joins, fever, butterfly-shaped rashes (Milar rash)
  • monitor LFTs monthly if pt has liver dz
  • DDI:
    • 2C19 and 3A4 inhibitor (weak) → increase levels of AED and warfarin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Pyrazinamide

A
  • MOA unclear but more active in acidic pH
    • active against dormant or semi-dormant TB in cytoplasm
  • prodrug→ pyrazinoic acid (POA)
  • SEs:
    • hepatotoxicity
    • N/V
    • hyperuricemia → gout attack
    • rashes
  • Monitoring:
    • LFTs with liver disease
    • uric acid levels (a good marker for compliance)→ gout problems
  • DDI: allopurinol, febuxostat, probenicid (PZA antagonizes effects)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Ethambutol

A
  • SEs:
    • optic neuritis → irreversible blindness
    • neuropathy, headache, dizziness, confusion
    • rashes, hepatotoxicity
  • Monitoring:
    • baseline visual acuity and color
      • espec in pts with renal insufficiency or therapy longer than 2 months
  • DDI:
    • antacids reduce absorption
      • should separate by 4 hours
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Treatment Interruptions for TB Intensive Phase

A
  • Initial phase:
    • 2 months with 4 drugs
  • <14 days: continue tx, if not totally completed in 3 months, restart from beginning
  • ≥ 14 days: restart from beginning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Treatment Interruptions for TB in Continuation Phase

A
  • Continuation phase:
    • ~4.5 months total of 2 drugs
  • <80% of planned doses completed
    • < 3 months → continue treatment, if not completed in 6 months, start from beginning
    • ≥ 3 months → restart 4-drug regimen from the beginning
  • ≥ 80% → additional tx may not be necessary
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Tx for Active TB

A
  • Preferred tx:
    • intensive phase interval: (RIF, INH, PZA, EMB)
      • 7 days/week for 2 months
      • 5 days/week for 2 months
    • Continuation phase interval: (INH, RIF)
      • 7 days/week for 18 weeks (4.5 months)
      • 5 days/week for 18 weeks (4.5 months)
  • Preferred alternative:
    • same intensive tx
    • Continuation Phase interval (INH, RIF)
      • 3 days/week for 18 weeks (4.5 months)
  • Alternatives: can do 3days/week for 8 weeks (4 drugs) then 3 days/week for 18 weeks (2 drugs) but caution with HIV pts
    • ***DO NOT USE twice weekly regimens for HIV pts****
17
Q

Tx for Latent TB

A
  • Once a week: INH + Rifapentine x 3 months
    • Not for: resistant cases, <2 yo, HIV/AIDs, Pregnancy
  • Twice a week: INH x 6 months
    • INH x 9 months for preggos
      • add Vitamin B6 to prevent neuropathy
    • ****NOT for resistant cases****
  • Daily: Rifampin x 4 months (not for preggos)
    • Rif + INH x 3 months
    • INH x 6 months
    • INH x 9 months
      • preferred for preggos+ Vitamin B6 and HIV/AIDS
    • *****Not for resistant cases*****
18
Q

Risk Factors of TB

A
  • location and birth place
  • ethnicity (Hispanic; asian; non-hispanic black)
  • age = 25-65
  • HIV infx
  • Recently (last 2 yrs) infected with TB bacteria
  • immunocompromised
  • abuses of alcohol or other illegal drugs
  • not treated correctly for TB in the past
19
Q

Elderly and Children TB sxs

A
  • Elderly:
    • mental status change = most common sxs
  • Children:
    • may present as atypical bacterial PNA due to immature cellular immunity → lower and middle lobes
    • extrapulmonary TB more common (i.e. lymph nodes, GI & GU, bone marrow, and meninges)
20
Q

Other TB drugs

A
  • Cycloserine
  • Ethionamide→ All the SEs
  • Streptomycin
  • Amikacin
  • Capreomycin
  • Paraaminosalicyclin
  • Levo/Moxi
  • Bendaquiline (Sirturo) → reserved for resistant cases, affects ATP synthesis (QT prolongation)