Streptomycin single dose is more effective than multiple small doses because it is -

Ans. is `a' i.e., Concentration dependent lytic effect Concentration dependent effect o 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 inhibitory 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, quinolones. Time-dependent effect o Concentration should be kept above the MIC for a high propoion of the time between each dose, i.e. action depends on the length of time the concentration remains above the MIC. o Examples are --> Macrolides & fi-lactams.