In addition, users may experience sweating, headache, blurred vision, dizziness, sleeplessness, and anxiety. Extremely high doses can cause a rapid or irregular heartbeat, tremors, loss of coordination, and even physical collapse. An amphetamine injection creates a sudden increase in blood pressure that can result in stroke, very high fever, or heart failure. In addition to the physical effects, users report feeling restless, anxious, and moody.
Higher doses intensify the effects.
Persons who use larger amounts of amphetamines over a long period of time can develop an amphetamine psychosis that includes hallucinations, delusions, and paranoia. These symptoms usually disappear when drug use ceases. Two commonly used stimulants are nicotine, found in tobacco products, and caffeine, an active ingredient in coffee, tea, some soft drinks and many non-prescription medicines. Used in moderation, these substances tend to relieve malaise and increase alertness. Although the use of these products has been an accepted part of our culture, the recognition of their adverse effects has resulted in a proliferation of caffeine-free products and efforts to discourage cigarette smoking.