Central Nervous System Stimulants
Central nervous system (CNS) stimulants are the most common type of medication prescribed for attention deficit hyperactivity disorder (ADHD). They have the longest track record for treating ADHD and have the most research to back up their effectiveness. Scientists are not sure exactly how CNS stimulants ease the symptoms of ADHD, but it is believed that these drugs work by increasing dopamine levels in the brain. Dopamine is a neurotransmitter (brain chemical) associated with motivation, pleasure, attention, and movement. For many people with ADHD, stimulant medications can increase their ability to concentrate and focus, while at the same time easing hyperactive and impulsive behaviors.
CNS stimulants for ADHD come in both short- and long-acting dosages. Short-acting stimulants peak after several hours and must be taken two to three times a day. These usually come in pill or capsule form. Long-acting or extended-release stimulants last eight to 12 hours and are usually taken just once a day, in the morning. Extended-release stimulants are the same drug as their short-acting forms; the difference is solely in the way in which the drug is delivered into the body. Extended-release stimulants too are usually taken in the form of a pill or capsule. However, an extended-release methylphenidate patch was recently put on the market as an alternative to oral ingestion. CNS stimulants used to treat ADHD include:
- Amphetamine-based stimulants (Adderall, Dexedrine, Dextrostat). These medicines are made up of either dextroamphetamine or a combination of dextroamphetamine and levoamphetamine.
- Dextromethamphetamine (Desoxyn)
- Dextromethylphenidate (Focalin)
- Methylphenidate (Concerta, Daytrana, Metadate, Ritalin)
CNS stimulants are highly addictive and should only be used under the supervision of a doctor. The medications can cause some undesired side effects, including decreased appetite, weight loss, problems sleeping, irritability when the medication wears off, and, in some rare cases, development of facial tics or heart-related conditions.
Although stimulants are commonly prescribed for pharmacologic treatment of ADHD, recent research has stated that the cardiovascular impacts of stimulants on children may be detrimental, especially in cases where a child has a pre-existing condition such as diabetes, hypertension, or heart-rhythm abnormalities. A practice-guidelines task force of the American Heart Association (AHA) and American College of Cardiology (ACC) recently revised their recommendations to include a provision about cardiovascular assessment and monitoring in children who require stimulant medication for ADHD. The US Food and Drug Administration (FDA) has also added warnings to the labels of stimulant medication to warn patients about an increased risk cardiovascular problems and psychiatric problems.
Nonstimulant medications are often considered when stimulants haven’t worked or have caused intolerable side effects.
Atomoxetine is one of only two nonstimulant medications approved by the FDA for ADHD treatment. As with CNS stimulants, scientists are not sure exactly why atomoxetine works. Atomoxetine, like stimulants, affects levels of neurotransmitters in the brain. However, unlike stimulants, which affect dopamine, atomoxetine boosts levels of the neurotransmitter norepinephrine. Atomoxetine is longer-acting than stimulant drugs; its effects last more than 24 hours.
Because it also has some antidepressant properties, atomoxetine may be a good option for ADHD patients who are also experiencing symptoms of anxiety or depression. However, atomoxetine doesn’t appear to be as effective as the stimulant medications for treating symptoms of hyperactivity. Side effects of atomoxetine can include nausea, sedation, reduced appetite, and weight loss.
Blood Pressure Medications (Guanfacine)
Guanfacine (Intuniv) is a nonstimulant approved by the FDA in 2009 for treating ADHD. In 2011, it was also approved as an adjunctive therapy option for use alongside CNS drugs in treating ADHD in children. Guanfacine is primarily a blood pressure medication, but it has also been shown in trials to effectively treat ADHD’s symptoms of hyperactivity, impulsivity, and aggression. It is less helpful when it comes to attention problems. Other blood pressure drugs (especially clonidine) are sometimes prescribed off-brand to treat ADHD.
Although the FDA has not approved antidepressants as a treatment for ADHD, doctors will sometimes prescribe this class of medication to those patients who do not respond well to stimulants or to atomoxetine.
Certain atypical, or second generation, antipsychotics, which target multiple neurotransmitters in the brain, are also sometimes prescribed off-brand to treat ADHD in patients who don’t respond well to stimulants or atomoxetine.