It does not matter if you take it before, with or after food. If ranitidine is prescribed twice a day, the best time to take it is in the morning and at bedtime. If ranitidine is prescribed once daily, the best time to take it is at bedtime.If you do not understand the instructions on the box, ask your doctor or pharmacist for help.anitidine works by decreasing the amount of acid made by the stomach. This helps reduce pain and also allows an ulcer and/or reflux disease to heal in most people. There is no evidence that this medicine is addictive.