Antitubercular Agents Flashcards

1
Q

Mechanism of Action of Streptomycin

A

inhibits CHON synthesis, irreversibly inhibit bacterial protein synthesis and binds to 30s subunit, causing a misreading of tRNA then leaving the bacteria unable to synthesize proteins

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2
Q

Mechanism of Action of Rifampin

S. mediterranei

A

inhibits RNA polymerase, inhibits DNA-dependent RNA polymerase activity by forming a stable complex w/ the enzyme
-suppresses initiation of RNA synthesis and leads to cell death

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3
Q

Mechanism of Action of Para Aminosalicylic Acid

A

Competitive inhibitor for PABA

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4
Q

Mechanism of Action of Ethionamide

A

Structural analogue of isoniazid

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5
Q

Mechanism of Action of Isoniazid

A

inhibits cell wall synthesis

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6
Q

First antibiotic for TB

A

Streptomycin

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7
Q

Most active agent and Enzyme inducer

A

Rifampin

S. mediterranei

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8
Q

For isoniazid resistant TB

A

Ethionamide

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9
Q

First line drug for short term tx

A

Pyrazinamide (Pyrazinecarboxamide)

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10
Q

Active form of Pyrazinamide

A

Pyrazinoic acid

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11
Q

First line

A

Isoniazid

Isonicotinic acid hydrazide

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12
Q

Basic red dye for leprosy, including dapsone resistant forms

A

Clofazimine

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13
Q

Combined with other agents (resistance develops rapidly)

A

Pyrazinamide (Pyrazinecarboxamide)

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14
Q

Streptomyces: S. orchidaceus, S. garyphalus, S. Lavendulus

A

Cycloserine

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15
Q

Streptomyces capreolus

A

Capreomycin

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16
Q

Adverse effects of Streptomycin

A

Ototoxicity, nephrotoxicity

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17
Q

Adverse effects of Rifampin

A

Reddish secretions

+ INH or ethambutol–> higher hepatotoxicity

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18
Q

Adverse effects of Clofazimine

A

Hyperpigmentation

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19
Q

Adverse effects of Para Aminosalicylic Acid

A

Severe GI irritation

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20
Q

Adverse effects of Ethionamide

A

Hepatotoxicity, Peripheral neuritis

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21
Q

Adverse effects of Ethambutol

A

Optic neuritis (red green color blindness)

22
Q

Adverse effects of Pyrazinamide (Pyrazinecarboxamide)

A

Hepatotoxicity

23
Q

Adverse effects of Isoniazid

Isonicotinic acid hydrazide

A
Hepatotoxicity
Peripheral neuritis (TX: pyridoxine)
24
Q

C6H7N3O

A

Isoniazid

25
Q

C5H5N3O

A

Pyrazinamide

26
Q

C10H24N2O2

A

Ethambutol

27
Q

C43H58N4O12

A

Rifampicin

28
Q

C21H39N7O12

A

Streptomycin

29
Q

C7H7NO3

A

Aminosalicylic Acid

30
Q

C8H10N2S

A

Ethionamide

31
Q

C12H12N2O2S

A

Dapsone

32
Q

absorption and bioavailability decreases when administered with food

A

Isoniazid

33
Q

active only at a slightly acidic pH

A

Pyrazinamide

34
Q

Mechanism of Action of Pyrazinamide

A

decrease pH (making the environment acidic) w/c retards the growth of M.TB and thereby inhibiting fatty acid synthesis

35
Q

Bactericidal and can penetrate human cells and exert lethal effect

A

Ethambutol

36
Q

Mechanism of Action of Ethambutol

A

inhibits arabinosyl transferase w/c is involved in cell wall biosynthesis
=bacterial cell wall complex production is inhibited leads to the increase of cell wall permeability

37
Q

Additional MOA of ethambutol

A

this can also inhibit the transfer of mycolic acid into the cell wall

38
Q

semisynthetic and has broad antibacterial spectrum

A

Rifampin

39
Q

aminoglycoside antibiotic

A

Streptomycin

40
Q

administered in association w/ isoniazid

A

aminosalicylic acid

41
Q

Optimal activity of aminosalicylic acid

A

ortho position

42
Q

can also be used to treat leprosy and may be bacteriostatic and bactericidal

A

ethionamide

43
Q

Mechanism of action of Dapsone

A

inhibition of folic acid synthesis in susceptible organisms

44
Q

resistant to isoniazid and rifampin

A

MDR-TB

45
Q

resistant to isoniazid, rifampin and fluoroquinolones

A

XDR-TB

46
Q

highly effective during the few months of therapy when inflammation changes are present

A

pyrazinamide

47
Q

more lethal to sites showing inflammation response ( pH is acidic at these locations

A

pyrazinamide

48
Q

used as adjunct in the tx of pulmonary TB

A

ethambutol

49
Q

bactericidal: acts on both intra and extracellular organisms

A

rifampin

50
Q

used for infections involving aerobic, g- bacteria such as Pseudomonas and Enterobacter

A

streptomycin