Antimycobacterials

Question 1

first line drug for treatment of TB

Answer 1

RIPE
Rifamycins (Rifampin and Rifabutin)
Isoniazid
Pyrazinamide
Ethambutol

Question 2

second line drug for treatment of TB

Answer 2

SALE
Streptomycin
Amikacin
Levofloxacin
Ethionamide

Question 3

used for treatment of C. difficile

Answer 3

Fidoxomicin
Metronidazole
Vancomycin

Question 4

drug regimen for latent TB and duration one should take the drug

Answer 4

Isoniazid for 6-9 months

Rifampin for 4 months

Question 5

mechanism of isoniazid

Answer 5

is a pyridoxine (vit B6) analogue that targets mycolic acid synthesis enzymes, enoyl acyl carrier protein reductase (AcpM) and b-ketoacyl-ACP synthase

Question 6

what activates isoniazid

Answer 6

mycobacterial catalase peroxidase

Question 7

pharmacokinetics of isoniazid

Answer 7

one can be a fast acetylator or a slow acetylator of the drug and fast acetylators required higher doses

Question 8

adverse effects of isoniazid

Answer 8

Lupus like syndrome
CYP450 inhibitor
Hepatotoxicity

Question 9

can isoniazid be used in pregnancy

Answer 9

yeah but must supplement with pyridoxine aka vit b6

Question 10

what are the rifamycins

Answer 10

rifampin and rifabutin

Question 11

mechanism of rifamycins (name them)

Answer 11

rifampin and rifabutin

binds to beta subunit of bacterial DNA dependent RNA polymerase hence blocking transcription –> inhibition of RNA synthesis

Question 12

preferred drug for treatment of TB in HIV positive patients

Answer 12

Rifabutin

Question 13

adverse effects of rifamycins (name them)

Answer 13

rifampin and rifabutin

CYP450 inducer
Orange colored secretions
GI distress

Question 14

mechanism of ethambutol

Answer 14

inhibits arabinosyl transferase involved in mycobacterial cell wall synthesis

Question 15

adverse effects of ethambutol

Answer 15

dose dependent visual disturbances

red green color blindness

Question 16

contraindications of ethambutol

Answer 16

children that are too young for vision tests

Question 17

mechanism of pyrazinamide

Answer 17

conversion of the drug to pyrazinoic acid lowering the pH of environment

Question 18

adverse effects of pyrazinamide

Answer 18

HAN

Hyperuricemia
Acute gouty arthritis
Non gouty polyarthralgia

Question 19

mechanism of ethionamide

Answer 19

congener of isoniazid

Question 20

drugs used to treat leprosy

Answer 20

Dapsone
Clofazimine
Rifampin

Question 21

mechanism of dapsone

Answer 21

dihydropteroate synthesis inhibition –> inhibition of folate synthesis

structurally similar to sulfonamides

Question 22

what is acedapsone

Answer 22

repository form of dapsone that provides inhibitory plasma concentration for several months

Question 23

adverse effects of dapsone

Answer 23

Erythema nodosum leprosum
Hemolysis esp in G6PD
CYP inhibitor

Question 24

mechanism of clofazimine

Answer 24

phenazine dye that bind to DNA to inhibit replication

also has redox properties that generate cytotoxic oxygen radicals

Question 25

adverse effects of clofazimine

Answer 25

red brown discoloration of skin (harmless)
GI irritation
eosinophilic enteritis