Pharmacology - Antimycobacterial Drugs Flashcards
What two mycobacteria species have cell envelops?
Mycobacteria tuberculosis
Mycobacteria leprae
What are the two targets of antimycobacterial drugs?
Early reactions of mycolic acid synthesis
Synthesis of NAG-arabinogalactan
Why are mycobacteria so well protected from antimycobacterial agents?
Cell envelope is thick, asymmetric, and highly impermeable to both hydrophilic and hydrophobic substances
Cell wall resist entry to antibiotics and organisms grow slowly
Name five drugs used against tuberculosis
Ethambutol Pyrazinamide Isoniazid Rifampin Streptomycin
Patient has active TB without a history of prior treatment and local prevalence of isoniazid resistance is greater than 4%. What is the appropriate therapy?
Four drug regimen
Patient has active TB without a history of prior treatment and local prevalence of isoniazid resistance is rare. What is the appropriate therapy?
Three drug regimen without ethambutol
What is the mechanism of ethambutol?
Decreases arabinogalactan synthesis by inhibiting the arabinosyl transferase that adds arabinose units to the growing arabinogalactan chain
What are the two targets to isoniazid action?
Inhibits mycolic acid synthesis
Target the FAS2 complex and is bactericidal
What is the advantage of using a multidrug approach against tuberculosis?
Reduces the chances of encountering preexisting resistance
Why does isoniazid have drug interactions?
Can inhibit or induce cytochrome P450 enzymes
What three drugs does isoniazid have interactions with?
Rifampin
Carbamazepine
Phenytoin
