Many coffee drinkers experience withdrawal symptoms, such as headaches, irritability, sleepiness, and lethargy, when they stop drinking coffee. Like any drug, the effects of caffeine on the body are not wholly good or bad ..Compared to other drinks, this means the caffeine levels oft Dr Pepper are MODERATE. However, it is also important to remember thatt Dr Pepper contains . mg of sugar. However, it is also important to remember thatt Dr Pepper contains . mg of sugar..Learn how much caffeine is in drinks such as coffee,e, and other popular soft drinks and teas. Check if some drinks may have hidden caffeine content..Caffeine Comparisons. Dr Pepper contains . mgs of caffeine per fluid ounce .mg ml ..