Antitubercular Drugs

Question 1

PULMONARY TUBERCULOSIS is known as?

Answer 1

“Koch’s Disease”

Question 2

In Gram staining: appears as “ghost”

Answer 2

Mycobacterium tuberculosis

Question 3

Acid-Fast staining of TB

Answer 3

“Ziehl-Neelsen stain”

Question 4

Isolated from Streptomyces mediterranei

Answer 4

RIFAMPICIN

Question 5

MOA OF Rifampicin?

Answer 5

Binds strongly to the bacterial DNA-dependent RNA polymerase and
thereby inhibits RNA synthesis (transcription),

Question 6

TRUE OR FALSE Rifampicin is a CYP450 Enzyme inducer?

Answer 6

TRUE

Question 7

Adverse effect of Rifampicin?

Answer 7

Red orange secretion

Question 8

Semi-synthetic derivative of Rifamycin

Answer 8

Rifampicin

Question 9

Other terms for Isoniazid?

Answer 9

1. Isonicotinic acid hydrazide
2. Isonicotinyl hydrazide (INH)

Question 10

Vitamin to manage peripheral neuritis caused by Isoniazid?

Answer 10

Pyridoxine/Vitamin B6

Question 11

MOA of Isoniazid?

Answer 11

Targets the enzymes acyl carrier protein reductase (InhA)
and β-ketoacyl-ACP synthase (KasA), which are essential for the
synthesis of mycolic acid

Question 12

A/E of Isoniazid?

Answer 12

1. Peripheral neuritis 2. GI disturbances
   (constipation, loss of appetite)
2. Hepatotoxicity.

Question 13

Synthetic analogue of nicotinamide

Answer 13

Pyrazinamide

Question 15

What is the active form of Pyrazinamide?

Answer 15

Pyrazinoic acid

Question 16

MOA of Pyrazinamide?

Answer 16

inhibit incorporation of mycolic acid in cell wall.

Question 17

Most hepatotoxic of all TB drugs; ↑ uric acid level → acute gouty arthritis.

Answer 17

Pyrazinamide

Question 18

MOA of Ethambutol?

Answer 18

Inhibits arabinosyl transferase—an enzyme important for
the synthesis of the mycobacterial cell wall (arabinogalactan).

Question 19

A/E of Ethambutol?

Answer 19

1. Retrobulbar neuritis (optic neuritis) impairing visual acuity
   and red-green color discrimination/blindness
2. hyperuricemia.

Question 20

Isolated from Streptomyces griseus

Answer 20

Streptomycin

Question 21

MOA of Streptomycin?

Answer 21

Irreversible inhibition of mycobacterial protein synthesis by binding to
30s ribosomal subunit.

Question 22

First antibiotic effective in the treatment of TB

Answer 22

Streptomycin

Question 23

A/E of Streptomycin?

Answer 23

1. Ototoxicity
2. vestibulotoxicity

Question 24

Structural analogue of p-aminobenzoic
acid (PABA) just like sulfonamides

Answer 24

Para-aminosalicylic acid

Question 25

MOA of PAS?

Answer 25

Folate synthesis antagonist that interferes with the incorporation of PABA into folic acid (inhibits folate synthesis / antimetabolite).

Question 26

Derivative of INH?

Answer 26

Ethionamide

Question 27

MOA of Ethionamide?

Answer 27

MOA: inhibition of O2 dependent mycolic acid synthesis.

Question 28

A/E of Ethionamide?

Answer 28

1. GI disturbances (N/V , intense gastric irritation) 2. neurological disturbances (confusion, peripheral neuropathy

Question 29

Isolated from the 3 different streptomyces species: - Streptomyces orchidaceous - Streptomyces garyphalus - Streptomyces lavendulus

Answer 29

Cycloserine

Question 30

MOA of Cycloserine?

Answer 30

Acts through a competitive inhibition of the D-alanine that is involved in bacterial cell wall synthesis.

Question 31

A/E of Cycloserine?

Answer 31

Toxicity: Dizziness, confusion, irritability, psychotic behavioural changes & suicidal tendency.

Question 32

Isolated from S. capreolus?

Answer 32

Capreomycin

Question 33

Reserved for the treatment of MDR-TB

Answer 33

Capreomycin

Question 34

Considered in the treatment of MDR tuberculosis after streptomycin & capreomycin.

Answer 34

Aminoglycosides

Question 35

Last line for TB used as an agent for Last-Resort for Multi-Drug Resistant TB.

Answer 35

Clafazimine

Question 36

A/E of Clofazimine?

Answer 36

Red-brown discoloration of the skin.