Stimulants are medications that increase heart rate, breathing rate, and brain function. Some stimulants affect only a specific organ, such as the heart, lungs, brain, or nervous system.
Some medications are given for their stimulant effect. For example, epinephrine 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.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.