Dr Pepper and its associated beverages, such as Diet Dr Pepper, Cherry Vanilla Dr Pepper, and Diet Cherry Vanilla Dr Pepper, all have caffeine. However, these flavors each have caffeine-free versions available. A 12-ounce serving of regular Dr Pepper contains about 42.6 milligrams of caffeine.
Caffeine is a stimulant that affects the central nervous system. It increases alertness, speeds up the heart rate, constricts blood vessels and relaxes air passages. It can also reduce motor coordination, cause insomnia and lead to physical dependence. The effects from caffeine can appear as quickly as 15 minutes after ingestion, and it remains in the body for several hours.
Dr Pepper is a blend of 23 flavors that was developed in Waco, Texas. It was introduced in 1885, one year before Coca-Cola, making it the oldest major soft drink brand in the United States.