How to adjust psychostimulant treatment if another medication affects urine pH

Question from a Member: How would you approach a patient taking methenamine hippurate twice a day for prevention of urinary tract infections (UTIs) along with lisdexamfetamine (Vyvanse®) for ADHD? Would the best approach be to take the methenamine only at bedtime, similar to the recommendation for vitamin C? My Epocrates did not list any interactions…