Inhibitors of Nucleic Acid Function Flashcards
How does gene transcription differ in prokaryotes from eukaryotes?
Transcription and translation are coupled. mRNA transcription begins while the mRNA is still forming.
What is DNA Gyrase?
Topoisomerase II- relaxes supercoiled bacterial chromosomes
What does RNA Primase do?
Acts as a polymerase for the lagging strand forming okazaki fragments
What does DNA polymerase II do?
Removes RNA primers from RNA Primase and replaces with DNA nucleotides
What does Topoisomerase IV do?
Separates the daughter chromosomes during cell division.
What targets Topoisomerase II &4
Quinolones and Fluoroquinolones
What targets DNA polymerase II
Rifampin
What fluoroquinolone can pass the Blood brain barrier
Oxfloxacin
What is the spectrum of Quinolones?
1st gen- Gram -
Newer- Gram - and Topo IV gives gram +
Why does targeting Topoisomerases effective and why does it not affect the host
Structural differences between humans and bacteria allow the targeting to only affect bacteria.
What is the 2nd generation fluoroquinone and what is its spectrum?
Ciprofloxacin
gram -, and gram + rods, intracellular atypical
What is the best fluoroqunione for Pseudomonas?
Ciprofloxacin
What to use to treat anthrax
Ciprofloxacin
What is the most common 3rd generation Fluoroquininone and what is its spectrum
Levoflaxacin
gram -, and improved atypical and Gram + activity
When is Levoflaxacin used?
In conjunction with other antimicrobials
What is the 4th generation Fluorquinone and what is its spectrum
Moxifloxacin- gram -/+ and anaerobes
What needs to be avoided with Fluoroquinones?
Al+, Mg+ and other divalents
Side effects of of Fluoroquinones
GI upset, headache, dizziness, photosensitivity, seizures (other underlying problems- epilepsy, use of theophylline inhaler for asthma, and use of NSAIDs), Disulfuram-Like effect
What causes C. difficile superinfection most often?
Ciprofloxacin
What are the rare risks of fluoroquinones?
Increased QT interval, worsens Myesthenia Gravis, Risk of rupturing tendons, possibly teratogen.
What drug inhibits DNA replication in anaerobic cells
Metronidazole
What is the drug of choice for Tetanus and C Difficile superinfection
Metronidazole
What is the side affect of Metronidazole
Disulfiram-Like interaction, dark urine, metallic tase and GI disturbance
What drug inhibits RNA Primase and what is its spectrum
Rifampin- Gram +/- and Mycobacteria
What are the side effects of Rifampin
Orange/Red bodily fluids, GI upset, Hepatoxicity, CYP450 inducer
What drug creates highly-reactive intermediates?
Nitrofurantoin- bactericidal
Side effects of Nitrofurantoin
Hepatotoxicty, neuropathy, pulmonary fibrosis, and drug-induced lupus
When should Nitrofurantoin not be used
Last 4 weeks of pregnancy or in neonates up to 1 month-hemolytic anemia
Patients with decreased renal function
Why use Nitrofurantoin for UTI?
90% absorbed into urine and 40% excreted in urine unchanged within 45 min so it stays in the bladder and is effective for treating susceptible UTIs.
