antimycobacterials Flashcards Preview

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Flashcards in antimycobacterials Deck (74)
1

First Line antimycobaterials

Isoniazid, Rifampacin, Pyrinizinamide, Ethambutol

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INH- MOA

Inhibits mycolic acid synthesis

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INH activation

KatG- only in Mb

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INH & liver enzymes

p450 inhibitor, metabolized in liver, various rates of acetylation

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INH distribution

All tissues- w/ high intracellular concentrations

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INH MOR

katG mutation

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INH- AE

Hepatitis, B6 deficiency- peripheral neuropathy, give pyridoxine, Inhibition of Phenytoin metabolism- ataxia

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INH method of admin

Oral

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INH Tmax

1-2 hr

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INH 1/2 life

.75-5h

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INH excretion

Kidney

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Rifampin- MOA

binds to beta subunit of Mb RNA pol --> inhibits transcription

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RIF method of admin

Oral- well absorbed

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RIF T1/2

2.5-5hr

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RIF- distribution

all tissues

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RIF & liver enzymes

CYP450 inducer

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RIF excretion

mostly feces, some urine

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RIF AE

Reddish/ brown Urine, Hepatitis, Abdominal discomfort, fever, skin eruptions

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RIF drug interactions

inc elimination of other drugs esp Birth control and HIV proteases- monitor the level

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RIfabutin

doesn't affect CYP450 so use in AIDs patients so don't inc elimination of PI

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Rifampimicin

Used for leprosy

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Pyrizinamide (PZA)- MOA

Pyrizinamidase converts it to pyrizinmatoic acid --> unknown MOA

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PZA method of admin

Oral

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PZA 1/2 life

9 hr

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PZA- distribution

well distributed in tissues but concentrates in cells

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PZA activity

active in acidic environments ie lysozomes inside of macropahges

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PZA metabolism

Liver

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PZA excretion

Kidney

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PZA AE

Hyperuricemia- Pyrazinoic acid inhibits renal secretion of Uric acid --> Gout monitor SGOT (liver enzyme) and uric acid, Heptatitis, Arthralgia, fever, skin rashes

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Ethambutol MOA

inhibits arabinosyl tranferase --> inhibits bac wall synthesis. Bacerial static

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Ethambutol admin

Oral

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Ethambutol 1/2 life

10 -15 h

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Ethambutol distribution

most tissues, including CNS --> used for TB meningitis

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Ethambutol excretion

Unchanged in urine

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Ethambutol AE

Retrobulbar neuritis- Optic neuritis w/o swelling of optic disc. R/G color blindness- Monthly tests for visual acuity. Peripheral neuritis, HA, Rash

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Streptomycin (SM)- use

occasionally used in conjunction with first line tax

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SM- admin

IV/ IM

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SM- tissue distribution

distributes to tissues, but doesn't concentrate in cells

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SM- excretion

Excreted unchanged in urine, no liver metabolism

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SM- AE

Ototoxicity- vistibular and auditory, renal injury, hypersensitivity

41

SM- MOA

binds 30s subunit of bac ribosome- prevents initiation complex formation. Inhibits translation

42

Paraminosalicylic Acid- PSA- MOA

competes with PABA for Mb dihyropterase synthase, interferes with folic acid and thus DNA synthesis. bacteriastatic

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PSA- admin

oral, well absorbed, always with food

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PSA- T1/2

2 hr

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PSA metabolism

Liver

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PSA excretion

Kidney

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PSA toxicity

GI- nausea, abdominal pain, diarrhea, nausea if not given w/ food. Goiter, hypothyroidism. Anemia

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Ethionamide- MOA

Inhibits mycolic acid synthesis

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Ethionamide- admin

Oral- well absorbed

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Ethionamide- distribution

wide

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Ethionamide- metabolism

Liver metabolizes it to ethionamide sulphoxide

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Ethionamide excretion

ethionamide sulphoxide- kidney excretion

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Ethionamide - AE

pyridoxine deficiency , GI- N/D/ pain, hepatotoxicity, allergic reactions

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Clofazamine- uses

Leprosy and Tb

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Clofazoamine- MOA

inhibits DNA synthesis

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Clofazamine- Admin

Oral

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Clofazamine T1/2

10 days

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Clofazamine distribution

widely. Concentrates in reticuloendothelil system and is slowly let out, partially accounts for long half life

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Clofazamine- excretion

metabolized to several inactive metabolites and excreted in the feces and urine

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Clofazamine - AE

Drug accumulation in tissues turns- skin, urine, and feces a red brown color, so people with leprosy don't like it b/c it marks them. GI disturbances

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Cycloserine/ kanamycin- MOA

inhibits cell wall synthesis

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Cycloserine/ Kanmycin- use

rarely used due to poor efficacy and adverse eventes

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Fluroquinolones-

Ciprofloxacin, Moxifloxacin, Levofloxacin

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Fluroquinolones- MOA

inhibit topoisomerase II

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Fluroquinolones- disrtibution

Low intracellular concentration

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Dapsone- use

Tx leprosy

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Dapsone- MOA

inhibits folate synthesis

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Dapsone- excretion

excreted into bile, reabsorbed, excreted in urine

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Dapsone- AE

well tolerated. Fever, GI, rash, exoliative dermatitis

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Dapsone Contratindications

Don't give to someone with sulfa drug allergies

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Second line Tb tx

Streptomyocin, Paramino Salacylic Acid, Ethionamide, Clofazamine, Cyloserine/ Kanomycin, Fluroquinolones, capreomycin

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Paucibacillary Tb- Tx

Rifampin& Dapsone for 6 months. Single lesion- Rifampin, ofloxacin, Minocycline

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Lepromatous MB- Tx

Rifampin, Dapsone, Clofazamine- 12 mos

74

M. avium Tx

Azithromycin, Ethambutol, Rifabutin, Fluroquinolones