NR565 WEEK 6 STUDY GUIDE
WEEK 6: CHAPTER 24: Drugs used in treating infectious disease
ANTIMYCOBACTERIALS
Mycobacteria- among the most difficult to cure (e.g. tuberculosis [TB])
o They grow slowly and are rel
...
NR565 WEEK 6 STUDY GUIDE
WEEK 6: CHAPTER 24: Drugs used in treating infectious disease
ANTIMYCOBACTERIALS
Mycobacteria- among the most difficult to cure (e.g. tuberculosis [TB])
o They grow slowly and are relatively resistant to drugs that are largely dependent on how rapidly cells are dividing
o Have a lipid-rich cell wall relatively impermeable to many drugs
o Are usually intracellular and inaccessible to drugs that does not have good intracellular penetration
o Have the ability to go into a dormant state
o Easily develop resistance to any single drugs
o Pregnancy categories:
Isoniazid: Pregnancy category A
Streptomycin: Pregnancy category D
The rest: Pregnancy category C
Fetal death- d/t TB: isoniazid + rifampin + ethambutol for TB tx if pregnant and if drug resistance is a possibility.
• Spectrum of coverage for various organisms/Pharmacodynamics
o Isoniazid - most active drug for tx of TB
Bactericidal- against susceptible mycobacteria (intracellular and extracellular organisms)
Interferes with lipid and nucleic acid biosynthesis in growing organisms.
Isoniazid and ethambutol- inhibits synthesis of mycolic acid (important constituents for mycobacteria cell walls and are not found in mammalian cells).
o Rifamycins – rifampicin, rifabutin, rifapentine
Bactericidal- against susceptible mycobacteria
Bind to the beta subunit of mycobacteria DNA-dependent RNA polymerase and inhibit RNA synthesis -> destruction of both multiplying and inactive bacilli.
Readily penetrate most tissues and can kill bacteria that are poorly accessible to many drugs.
Rifampin and rifabutin: N. gonorrhoeae, staphylococci, streptococci, Mycobacterium leprae, MAC, and H. influenzae type B.
Rifampin-resistance develop rapidly when used as monotherapy- should be combined with another active abx for tx of established infections.
o Ethambutol
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