Stimulants are drugs that increase your heart rate, breathing rate, and brain function. Some stimulants affect only a specific organ, such as the heart, lungs, brain, or nervous system.
Epinephrine is a stimulant. It is given during cardiac arrest to make the heart beat.
Other times, stimulants can cause unwanted side effects. For example, pseudoephedrine found in some cold medicines can increase the heart rate.
Taber's Medical Dictionary Online website. www.tabers.com/tabersonline. Accessed March 7, 2019.