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CNS stimulants

Medically reviewed by Carmen Pope, BPharm. Last updated on April 11, 2023.

What are CNS stimulants?

CNS (central nervous system) stimulants are medicines that stimulate the brain, speeding up both mental and physical processes.

They increase energy, improve attention and alertness, and elevate blood pressure, heart rate and respiratory rate. They decrease the need for sleep, reduce appetite, improve confidence and concentration, and lessen inhibitions.

Experts aren’t exactly sure how CNS stimulants work, although they suspect they increase levels of one or more neurotransmitters in the brain, such as dopamine, norepinephrine, or serotonin. They may also have other effects, depending on the actual drug. For example, phentermine possibly indirectly increases leptin levels – leptin is a substance that tells us we feel full.

What are CNS stimulants used for?

CNS stimulants may be useful for the treatment of certain conditions characterized by symptoms such as prolonged fatigue, inability to concentrate, or excessive sleepiness. CNS stimulants may also be used to help with weight loss in people who are morbidly obese. CNS stimulants have been used for the following conditions:

Unfortunately, some people misuse CNS stimulants for their ability to increase energy levels. Some CNS stimulants also create a brief feeling of euphoria or temporarily increase self-confidence.

What are the differences between CNS stimulants?

CNS stimulants differ in their ability to increase levels of certain neurotransmitters which determines what effect they have in the body and their side effects.

There are also differences in the length of time they act for in the body and how quickly they start to work. Some CNS stimulants have been modified to improve their effect, for example, a methyl group was added to amphetamine to make methamphetamine which lasts longer than amphetamine, penetrates the brain better, and is less likely to detrimentally affect the heart.

Are CNS stimulants safe?

CNS stimulants have many unpleasant side effects and deaths have resulted from their misuse.

They are widely abused and highly addictive. Withdrawal symptoms can be very harsh which encourages repeated and frequent misuse to maintain the high. Addiction can happen quickly after just a few uses; or in some cases, one use. Tolerance occurs, which means more of the substance needs to be taken to maintain the desired high.

Misuse of CNS stimulants can cause severe paranoia and psychosis, severe depression and suicidal thoughts. It can lead to a break down in relationships and affect a person’s ability to keep a job. Drug seeking behavior can take over a person’s life to the extent that their nutrition suffers. Illness and sexual dysfunction are also common in people who misuse CNS stimulants.

What are the side effects of CNS stimulants?

CNS stimulants are associated with a number of severe and undesirable side effects such as:

In addition, a dry mouth, unpleasant taste in the mouth, or gastrointestinal disturbances (nausea, diarrhea, or constipation) may also occur.

For a more extensive list of side effects, click on the individual drugs.

List of CNS stimulants

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.