Drugs

Question 1

Isoniazid (INH):

• MOA?
• Cidal/static?
• PK?
• Toxicity? (2)
• Resistance? (2)
• Route?
• Spectrum? IC activity?

Answer 1

• Decreases synthesis of mycolic acid; bacterial catalase peroxidase (katG) needed to convert to active form
• Cidal for active; static for latent
• Different acetylator speed makes a difference on levels/dose
• Hepatotoxicity, Neurotoxicity (B6 Pyrodoxine)
• Rapidly via inhA/katG mutations
• Oral
• Mycobacteria only; Good

Question 2

Rifampin:

• MOA?
• Selective toxicity?
• Route?
• Spectrum?
• IC activity?
• Resistance? Effect what?
• Toxicity? (3)

Answer 2

• Cidal inhibition of RNA polymerase initiation
• Bacteria have different RNA polymerase
• Oral
• Myco + gram (+)
• good
• RNA poly (rpoB); mitochondria
• Minor hepato; red/orange fluids; (rifabutin in HIV because it doesn’t effect p450)

Question 3

Ethambutol:

• MOA?
• Selective toxicity?
• Route?
• Spectrum?
• IC activity?
• Good aspect? Bad?
• Resistance?
• Toxicity? (2)

Answer 3

• TB static; other myco-cidal; inihibits arabinosyl transferase
• arabinosyl transferase
• Oral
• Myco only
• Modest
• Good lung distribution; doesn’t penetrate macs but can hit mitochondria
• emb genes
• optic neuropathy (red-green color blind); gout

Question 4

Pyrazinamide:

• MOA?
• Selective toxicity?
• Route?
• Spectrum?
• IC activity?
• Resistance?
• Toxicity (2)
• Pregnancy?

Answer 4

• Cidal unknown MOA
• Not known
• Oral
• Myco only
• Variable
• pncA gene
• Gout, hepatotoxicity
• NOT IN PREGNANCY!!!

Question 5

Streptomycin:

• MOA?
• Selective toxicity?
• Route?
• Spectrum?
• IC activity?

Answer 5

• Cidal inhibition of protein synthesis
• Aminoglycoside
• IV
• Myco + gram (-)
• Poor

Question 6

• Leprosy treatment? (2)

- Myco aviuum treatment? (4)

Answer 6

• Dapsone (static PABA antagonist) + rifampin

- Macrolides; Ethambutol; FQ’s; Rifabutin