Im wondering what the difference is if i take 10mg valium twice a day or just take 20mg at once, wouldnt the effect last the same amount of time? For example if i take 10mg at 9am and another 10mg at 5pm why not just take it once at 9am to save from having to take it twice? Same goes for any other meds im just curious what the difference is if the medication will last the same amount of time either way. Same goes for Lyrica im on 75mg twice a day what would be the difference if i just took 150mg once a day?