 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  and weight. Methenamine works better if your urine is more acidic. Your doctor may test the acidity of your urine (urine pH). If necessary, your doctor may recommend ways to increase urine acidity (such as by taking vitamin C/drinking cranberry juice, limiting foods that decrease acidity/increase alkalinity such as milk products/most fruits, adjusting alkalinizing medications). See also Drug Interactions section. Follow your doctor's instructions. For the best effect, take this drug at evenly spaced times. To help you remember, take this medication at the same time(s) every day. Keep taking this medication for the full time prescribed, even if you feel well. Skipping doses or stopping the medication too early may allow bacteria to continue to grow, which may result in a return of the infection and make the bacteria more difficult to treat (resistant). Do not take more of this drug than directed because it may increase your chance of side effects. Tell your doctor if symptoms of a urinary tract infection return (such as burning/painful/frequent urination).The side effects of Methenamine Hippurate Oral: Nausea, vomiting, diarrhea, abdominal cramps, and loss of appetite may occur. If any </s>