Antimycobacterial drugs Flashcards

1
Q

first line drugs for tuberculosis

A

rifampin
pyrazinamide
ethambutol
isoniazid

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2
Q

second line drugs for tuberculosis

A
rifabutin
rifapentine
fluoroquinolone
capreomycine
ethionamide
amikacin
kanamycin
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3
Q

ISONIAZID ROA

A

oral

parenterally

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4
Q

isoniazid MOA

A

inhibit synthesis of mycolic acid

activated by catalase-peroxidase encoded by KatG gene

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5
Q

resistance to isoniazid

A

mutation of the KatG gene

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6
Q

isoniazid bactericidal or bacteriostatic?

A

bactericidal

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7
Q

isoniazid indication

A

bactericidal - M. tuberculosis and M.kansasii
M. avium-intracellulare
LATENT TB
prevent TB in neonates and children in close contact
prophylaxis: if + for tuberculin, HIV+ and recent exposure

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8
Q

AE isoniazid

A

Hepatitis (age dependent)
Peripheral neuritis: drug induced pyridoxine deficiency (B6) (paresthesia, numb finger and toe)
RARE: toxic encephalopathy and hematologic; granulocytosis, anemia, thrombocytopenia

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9
Q

ETHAMBUTOL bactericidal or bacteriostatic?

A

bacteriostatic

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10
Q

ethambutol roa

A

orally (w other drugs TB and M. AI

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11
Q

ethambutol moa

A

inhibit arabinosyl transferase and synthesis of arabinogalactan for cell wall

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12
Q

ethambutol resistance

A

mutation in arabinosyl transferase

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13
Q

AE ethambutol

A

Optic neuritis
impaired green-red color discrimination (retrobulbar neuritis)
CI in children to young to assess visual activity)
hyperuricemia, GOUT
hepatitis, thrombocytopenia

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14
Q

Pyrazinamide bactericidal or bacteriostatic?

A

bactericidal

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15
Q

pyrazinamide moa

A

orally given for M.TB, given in combination with isoniazid, ethambutol and rifampin

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16
Q

pyrazinamide MOA

A

nicotinamide derivative, converted in mycobacteria to active metabolite pyrazinoic acid by pyrazinamidase

inhibit fatty acid synthesis and translation

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17
Q

pyrazinamide resistance

A

mutation in pyrazinamidase

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18
Q

pyrazinamide AE

A

arthralgia
hyperuricemia and gout
hematologic toxicity
hepatitis and increase in serum ion concentration

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19
Q

pyrazinamide contraindicated

A

in pregnant women

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20
Q

Rifampin - broad or narrow spectrum?

A

broad

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21
Q

rifampin ROA

A

oral/IV

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22
Q

rifampin MET

A

converted in the liver after oral administration to active desacetyl - rifampin. widely distributed to tissue and fluid.
enterohepatic cycling

23
Q

rifampin indications

A

M.TB -> rifampin, isoniazid, ethambutol and pyrazinamide
M.kansasii
M.AI
M.leprae
Tubercular meningitis
Latent TB (alterative isoniazid)
Prevent; exposed to H.influenza, who can transmit to children under 4 unvaccinated
Meningococcal disease - in those close contact
treat - Legionella pneumophila with macrolide or fluoroquinolone

24
Q

Rifampin MOA

A

binds to B subunit of DNA - dependent RNA polymerase, inhibit transcription

25
Q

Rifampin resistance

A

decreased affinity of RNA polymerase. NEVER USE ALONE

26
Q

rifampin AE

A

hepatitis (don’t drink alcohol)

hypersensitivity, fluelike illness w chills (large doses)

nephrotoxicity (light chain proteinuria)

discontinue if purpura develops

reddish-orange-brown discoloration of SALIVA; TEAR; UriNE
induces cytochrome P450; accelerate metabolism of other drugs -> macrolides, benzodiazepines, calcium blocker, digoxin, sulfonylureas, theophylline, warfarin, estrogen

27
Q

Rifapentine - what is it derived from?

A

derived from rifamycin

28
Q

rifapentine - indication

A

pulmonary TB by M.TB

29
Q

2 phase regimens rifapentine

A

twice weekly rifapentine w isoniazid, ethambutol ad pyrazinamide for 2 months

for 4 months rifapentine and isoniazid

30
Q

rifabutin MOA

A

inhibit DNA dependent RNA polymerase

31
Q

rifabutin indication

A

Treat TB in HIV infected (not rifampin, cannot use w protease inhibitor)
prevent M.avium-intracellulare infection

32
Q

rifabutin ROA

A

orally w food, to avoid irritation (lipophilic)

33
Q

rifabutin AE

A

induce cytochrome P450

34
Q

bedaquiline note

A

can be given orally one daily for 2w and 3 w for 22 weeks. should be given in common w at least 3 other drugs to which patients isolate is susceptible

35
Q

bedaquiline MOA

A

blocking proton pump for ATP synthase in M.TB

36
Q

bedaquiline indication

A

MDR-TB

37
Q

bedaquiline ROA

A

orally

38
Q

bedaquiline AE

A

electrocardiogram bf starting, and at regular intervals after

prolonged QT; arrhythmia and sudden death: block of depolarizing K+ channels

advese liver reaction

interacts with cytochrome P450: mentoring!! e.g rifampin reduces bed aquiline, so montoring needed

monitor electrocardiogram, liver reaction and CYP450

39
Q

drugs for m. avian intracellular infection

A

ethambutol, rifampin, rifabutin
azithromycin, clarithromycin
ciprofloxacin

40
Q

used to prevent MAC infections in HIV/ immunocompetent patients

A

azithromycin, clarithromycin and rifabutin

CAR

41
Q

drugs combined to use for MAC

A

pulmonary and other MAC infections:
azithromycin, ethambutol, rifabutin or rifampin (rifabutin if immunocompromised)

16-24 weeks

42
Q

alternative for MAC in immunocompromised

A

clofazimine + streptomycin (contraindicated in pregnant women)/ amikacin

43
Q

drugs for leprosy

A

MD therapy indicated

44
Q

sulfones (dapsone) MOA

A

inhibit synthesis of folic acid by M.leprae (BACTERIOSTATIC)

45
Q

sulfones (dapsone) ROA

A

orally w other drugs

46
Q

sulfones (dapsone) AE

A

glucose 6 - phosphate deficiency - hemolytic anemia

gastrointestinal disturbances

peripheral neuropathy

optic neuritis and blurred vision

proteinuria, nephrotic syndrome, SLE like syndrome

47
Q

sulfones (dapsone) MET

A

metabolized by acetylation. so people with high levels of acetyl-transferase activity have low level of drug

48
Q

Rifampin

A

great bactericidal activity agains M.leprae

combined w dapsone

or dapsone+clofazimine

49
Q

Clofazimine - facts

A

antimycobacterial and antiinflammatory effects

enhances phagocytic activity of neutrons and macro

penzydine dye

50
Q

clofazimine - indications

A

bacteriocidal - M.TB

bacteriostatic - M.leprae

active - M.AI

51
Q

Lepromatous leprosy

A

Clofazimine in combo w dapsone and rifampin

antiinflammatory
tuberculoid leprosy -> dapsone + rifampin

52
Q

Clofazimine MET

A

slowly and incompletely absorbed from gut

highly lipophilic and widely distributed to tissues
70 days half-life

53
Q

Clofazimine AE

A

Gi distress

Photosensitivity

Discoloration of body secretion and skin

Hepatitis so contraindicated in hepatic disease

54
Q

Thalidomide

A

phocomelia

immunomodulating actions

orphan drug - TB, leprosy, erythema nodosum leprosum

ability to stimulate Tcells (CD8+)