Anti-TB (Antimycobacterials) Flashcards
What three characteristics are specific to Mycobacterium?
- Acid-fast staining
- Mycolic acid
- Arabinogalactin
What is the DOC for ACTIVE TB?
RIPE
- Rifampin
- Isoniazid
- Pyrazinamide
- Ethambutol
Under what conditions would you substitute Rifabutin for Rifampin in the treatment of TB? Why (2)?
Rifabutin for Rifampin if HIV+ or concerned about drug interactions (other med is an inducer of CYP3A4)
What is the DOC for LATENT TB? What are two alternative options?
Isoniazid + Rifapentine
- Isoniazid monotherapy
- Rifampin monotherapy
What is the MOA of Isoniazid? What is it activated by?
Inhibition of mycolic acid
- Activated by KatG (possible MOR)
What should be considered with metabolism of Isoniazid, and why is this important?
Fast vs. Slow acetylators
- Changes toxicity…
What are the three primary toxicities associated with Isoniazid?
- Hepatotoxicity
- Hemolysis and G6PD deficiency
- Peripheral neuritis
Remember INH (injury to nerves and hepatic)
What is the MOA of the Rif family? What three drugs are included in this family and how is each used?
Rif MOA: inhibit RNA polymerase via rpoB subunit (possible MOR)
- Rifampin: active TB (RIPE) OR mono latent TB
- Rifabutin: substitute for Rifampin if HIV+ or drug interactions in active TB
- Rifapentine: latent TB (combine with Isoniazid)
What are the three primary toxicities associated with Rifampin?
- Drug interactions (induces CYP3A4)
- Orange-colored secretions
- Decreased BP effectiveness
What is the MOA of Ethambutol?
Inhibition of arabinogalactin synthesis
What is the primary toxicity associated with Ethambutol?
Visual issues (R/G color blind, blindness)
What is the MOA/what conditions are necessary for Pyrazinamide to be active?
MOA: unknown…
- Requires acidic environment
What is the primary toxicity associated with Pyrazinamide?
Hepatotoxicity
What two antimycobacterials are associated with Hepatotoxicity?
- Isoniazid
- Pyrazinamide
Why is Isoniazid PLUS Rifapentine considered the DOC for latent TB over monotherapy Isoniazid or Rifampin (2)?
Rifapentine has a longer half-life so fewer doses AND reduced side effects (compared to monotherapies)
Why are the second line antimycobacterials considered second line?
Less effective AND more toxic
What is the DOC for MAC (Mycobacterium avium complex) - think ___ + ___ + ___)?
- Azithromycin OR Clarithromycin PLUS - Ethambutol PLUS - Rifampin OR Rifabutin OR Cipro
In the treatment of MAC (Mycobacterium avium complex), why would you choose Azithromycin over Clarithromycin?
Why would you choose Rifampin OR Rifabutin over Cipro, and vice versa?
- Azithromycin over Clarithromycin if drug interactions
- Rifampin OR Rifabutin if patient is <18 (Cipro is contraindicated)
- Cipro if drug interactions (Rifampin, Rifabutin are strong inducers of CYP3A4)
What is the DOC to treat Leprosy (Mycobacterium leprae) - think ___ + ___)?
Rifampin + Dapsone
What is the MOA for Dapsone? What is Dapsone’s primary toxicity?
What does is treat?
- MOA: Inhibits folic acid synthesis
- Toxicity: nasal obstruction
Treats Leprosy (Mycobacterium leprae)
What drug is used to treat the symptoms of Leprosy (Mycobacterium leprae), and what is that symptom? What should be considered with the use of this drug?
Thalidomide treats ENL
- VERY TOXIC - Teratogenic (not for pregnancy
