Infection of urinary tract if the pH of urine is made alkaline
There is a huge misconception here.  Morphine overdose is treated with Narcan (naloxone).  Phenobarbiton overdose is treated with artificial respiration (in extreme cases), blood pressure medication, and management of low heart rate.  The concept of lowering the pH of the urine to increase a drug excretion is (to my knowledge) never used in emergency settings.  Dialysis, which filters the blood, would be used to 'clean' the blood of toxins.  Think about it.  Time is life, and changing the composition of your fluids would take a lifetime compared to the implemented measures in emergency rooms.  You body has an extremely sensitive acid-base balance.  You do not want to try to increase or decrease the pH of your bodily fluids.