Antibitoics IV: Nucleic Acid Membrane Disruptors Flashcards
Prototype fluoroquinolone
Ciprofloxacin
Fluoroquinolone MOA
Direct inhibition of DNA synthesis by binding directly toDNA-topoisomerase complexes; bactericidal
Boxed warnings for fluoroquinolones
Neuromuscular blockade (contraindicated in myasthenia gravis)
May occur together: tendon rupture, seizures, peripheral neuropathy)
Other side effects of fluoroquinolones
Prolonged QT interval
Hypoglycemia
Photosensitivity
Fluoroquinolone contraindications
Pts under 18
Myasthenia gravis
Nitroimidazole drug
Metronidazole
Metronidazole MOA
Bactericidal prodrug that is converted to active form in anaerobes by ferredoxin reductase cycle
Produces free radicals that cause lethal DNA strand breaks
Nitroimidazoles are narrow spectrum, only active against ____
Anaerobes
Adverse reactions of nitromidazoles
Dark urine
Peripheral neuropathy
Metallic taste
Boxed warning for nitroimidazoles
Carcinogenic; only use when necessary
Nitroimidazole drug interaction
Alcohol (flushing, tachycardia, headache, nausea)
Folic acid is essential for synthesis of ___ and ____
Nucleic acids and amino acids
Most bacteria must _____ folate
Synthesize (can’t absorb it)
Antifolates act on which enzyme?
Dihydrofolate reductase (DHFR)
Sulfonamide MOA
Structural analog of PABA component of folic acid
Competitive inhibitor of dihydropteroate synthase in bacteria which blocks formation of dihydropteroic acid
Bacteriostatic
Sulfonamide drug
Sulfamethoxazole
Adverse reactions for sulfonamides
Kernicterus in neonates
Hypersensitivity rash
Hemolytic anemia in pts with G6PD deficiency
Trimethoprim MOA
Competitive inhibitor of bacterial DHFR
Adverse reactions of trimethoprim
Bone marrow suppression if pt has folate deficiency
Hyperkalemia
Co-trimoxazole (Bactrim) is a combination of:
Trimethoprim and sulfamethoxazole
Co-trimoxazole is very broad spectrum, effective against aerobic G+ and - bacteria and ____
MRSA
Opportunistic fungal pathogens
Cyclic lipopeptide prototype drug
Daptomycin
Cyclic lipopeptide MOA
Inserts lipophilic tail into plasma membrane to cause K+ effluent, leading to depolarization and kills the bacteria
Daptomycin is only effective against G + or - bacteria?
G+
Daptomycin adverse reactions
Myopathy (monitor CK)
Eosinophilia pneumonia
Polymyxin prototype drug
Colistin
Polymyxin MOA
Hydrophobic tail has detergent-like effect that disrupts outer and inner membranes to increase cell permeability
Polymyxins can be administered ____ or ______
Topically (Neosporin) or by IV
Polymyxins adverse reactions
None for topical use
Nephrotoxicity and neurotoxicity with IV use