Theoratically you should space out the doses as evenly as possible over 24 hours ie: four times a day - every 6 hours, three times a day - every 8 hours. But in reality all doctors and pharmacists know that patients won't want to get up in the middle of the night to take them so recommend spacing out the doses evenly throughout the wakjng day eg if you are awake at 8am and go to bed at 11pm - four times a day take at 8am, 1pm, 6pm, 11pm. Three times a day take at 8am, 3pm, 10pm. Hope this helps!!