One of the most common complaints I hear from patients is that liquid antibiotic prescriptions never last as long as they’re supposed to. The reason this happens is because most antibiotics come in set amounts and pharmacists are not allowed to add extra to make sure patients do not run out early. To get around this policy, I calculate how much a child needs for a full-course of treatment and then prescribe the next larger size bottle. For example, if a child is taking 1 tsp of amoxicillin twice a day for ten days, he needs a 100 ml bottle. When I fill out the area on the prescription that says how much the pharmacist should dispense, I write 150 ml instead of “ten-day supply.” You can ask your doctor to do the same thing.