Mechanism of Action of quinolones ?
Ans. is 'b' i.e., Inhibiting DIVA gyrase o Drugs inhibiting ceil wall synthesis - b-lactam antibiotics (Penicillin, Cephalosporins, monobactoms, Carbapenems), Cycloserine, bacitracin, vancomycin, fosfomycin.o Cause leakage from cell membrane - Polypeptides (Polymyxins, Colistin, tyrothricin), Polyenes (Amphotericin B, Nystatin, Hamvcin), Azoles (Ketoconazole, fluconazole, intraconazole)o Inhibit protein synthesis - Tetracyclines, Chloramphenicol, Erythromycin, Clindamycin, Linezolid.o Cause misreading of m-RNA code and affect permeability-Aminoglycosides,o Inhibit DMA gyrase - Nalidixic acid and fluoroquinolones,o Interfere with DIN A function - Rifampin, metronidazole,o Interfere with DNAsynthesis - Acyclovir, zidovudin.o Interfere with intermediary metabolism - Sulfonamide, Sulfones, PAS, trimethoprim. Pyrimethamine, EthambutoLConcentration dependent effect of quinoioneso The outcome is related to the peak antibiotic concentration achieved at the site of infection in relation to the minimum inhibitory concentration.o The killing effect of a drug is high when ratio of peak concentration to MIC is more.o These drugs produce a prolonged inhibitor),' effect on bacterial multiplication (post antibiotic effect) which suppresses growth until the next dose is given.o So. these drugs produce better action when used as a large single dose as compared to same daily dose divided into 2-3 times.o Example-Aminoglycosides,quinoiones,
Inhibiting DHFR
Inhibiting DNA gyrase
Inhibiting protein synthesis
Inhibiting cell wall synthesis
Quinolones