<prompt> An 18-year-old man who is known to have non penicillinase producing gonococcal urethritis is given an injection of penicillin and probenecid. What is the mechanism used by probenecid that makes penicillin more efficaciousPromotes entry of the penicillin into the bacteriaProlongs the duration of action by affecting the liver metabolism of penicillinDecreases the bacterial resistance by inhibiting penicillinase productionIncreases the half-life and serum level by decreasing the renal excretion of penicillin  <response>: Probenecid decreases the renal excretion of penicillin, thereby increasing both the half-life and the serum level. Ref:- KD Tripathi 