- The use of caffeine containing products and alcohol is not allowed from 12 hours prior to all study visits and during in clinic stays. All other times, alcohol consumption and caffeine intake are limited to no more than 2 alcoholic beverages or equivalent (beer [284 mL/10 ounces], wine [125 mL/4 ounces], or distilled spirits (25 milliliter [mL/1 ounce]) per day and caffeinated beverages will be limited to no more than 2 units per day amounts (1 unit=120 milligrams [mg] of caffeine). Strenuous activity is not allowed from 1 week prior to admission until the follow-up visit.