Anti-fungal, anti TB (no fungal yet)

Question 1

What drugs should i not use for pt suspected of TB

Answer 1

Respiratory quinolones, Levo and Moxi as it will mask symptoms

Question 2

What is the treatment course for TB

Answer 2

2 months intensive care of RIPE or RIPS
followed by 4 months continuation of daily or 3x a week RI

Question 3

Adverse reactions to RIPE

Answer 3

All four: pruritis

RIP:
GI symptoms eg. abdominal discomfort, nausea, anorexia
Hepatotoxicity

Question 4

rank drugs in terms of hepatotoxicity, starting with least to most

Answer 4

RIP

Question 5

Rifampicin acts on what kind of bacilli

Answer 5

metabolically active and in stationary phase

Question 6

Rifampicin (MOA, administration, metabolism, can be used in pregnancy, caution, SE)

Answer 6

MOA: Block DNA dependent RNA polymerase

Orally administered, well absorbed

Hepatic metabolism

Use in pregnancy cos benefit > risk
Induce CYP450

Orange discolouration of bodily fluids

Question 7

What can isoniazid act on

Answer 7

Used for active and latent TB

Question 8

MOA of Isoniazid

Answer 8

Prodrug

Activated by catalase-peroxidase enzyme
Activate Isoniazid → Produce free radicals → Inhibit mycolic acid of bacterial cell wall

Question 9

characteristics of isoniazid (administration, pregnancy, caution)

Answer 9

oral, well absorbed
can take for pregnancy
Should take with Pyridoxine (Vitamine B6) to prevent peripheral neuropathy

Question 10

What does Pyrazinamide target

Answer 10

persistent bacteria that cause relapse

Question 11

MOA of Pyrazinamide

Answer 11

Prodrug
Converted to Pyrazinoic acid (active form) by pyrazinamidase enzyme in TB
Accumulation of Pyrazinoic acid decreases intracellular pH, cause inactivation of critical pathways necessary for survival of bacteria

Question 12

Adverse effects of Pyrazinamide (5 points)

Answer 12

GI symptoms eg. nausea, vomiting

Photosensitivity

Hepatotoxicity
Most hepatotoxic TB drug

Hyperuricemia
Gout like symptoms, pain in joints
Pyrazinoic acid inhibits renal tubular secretion of uric acid

Itch, widespread rashes

Question 13

What does Ethambutol act on

Answer 13

rapidly growing bacilli

Question 14

MOA of Ethambutol

Answer 14

Interfere with mycobacterial cell wall
Inhibit arabinosyltransferase enzyme → interfere with the polymerisation of arabinose into arabinogalactan (primary polysaccharide)

Question 15

Adverse effects of Ethambutol

Answer 15

Visual toxicity (E for eye)
Decrease in visual acuity, red-green colour blindness, blindness, central scotoma

Hyperuricemia / gout

Question 16

Indication for streptomycin in TB

Answer 16

Can replace ethambutol in intensive treatment (2 months)