Central nervous system stimulants
Central nervous system (CNS) stimulants are medicines that speed up physicaland mental processes. They are used to treat attention-deficit hyperactivitydisorder (ADHD), narcolepsy, and other disorders of the central nervous system. The most commonly used and well-known central nervous system stimulant iscaffeine (also known as an analeptic drug). Other stimulants include amphetamines, such as dextroamphetamine sulfate (Dexedrine, DextroStat) and methamphetamine hydrochloride (Desoxyn), and nonamphetamine drugs such as, pemoline (Cylert), and methylphenidate (Ritalin). While the effects caused by CNS stimulants are dramatic, the therapeutic usefulness of these medications is limiteddue to their side effects.
CNS stimulants increase attention, decrease restlessness, and improve physical coordination in people who have ADHD, a condition in which people have unusually high activity levels and short attention spans. The drugs may also curbimpulsive and aggressive behavior related to ADHD. Experts indicate that almost 30 percent of young people with ADHD are not diagnosed until middle school or later. While very young children are inattentive and impulsive, this hyperactivity often quiets in teenagers to a restlessness. A diagnosis of ADHD is made solely on guidelines set by the American Psychiatric Association, as there is no biological test to indicate the condition. The exact cause of ADHDis not known, but research has found that it affects several within a family.
Although central nervous system stimulants are effective in treating ADHD, their use is controversial, especially in children. Experts advise that medication is not a cure for ADHD, and should not be used as the only treatment strategy for the condition. It is uncertain how CNS stimulants exactly work in treating ADHD. Possible side effects in children include weight loss, loss of appetite, or problems falling asleep. When used over long periods, CNS stimulants may interfere with growth and cause unwanted behavioral effects, such asdevelopment of a tic disorder, and problems with thinking or social interaction. Parents whose children need to take these drugs should thoroughly discussthe risks and benefits with the child's doctor. The doctor may recommend periodic "drug holidays," during which time the child stops taking the medicine.Those who need the stimulant only for paying attention may not need it whenschool is not in session, or may only need a morning dose if difficult subjects are taught in the morning.
The following are several stimulant medicines approved by The Food and Drug Administration for treating ADHD: methylphenidate (Ritalin and generics), dextroamphetamine (Dexedrine and generics), methamphetamine (Desoxyn), and an amphetamine-dextroamphetamine combination (Adderall). Recently, the FDA restricted the approved stimulant pemoline (Cylert), to secondary use, due to its link to liver failure.
Narcolepsy, in which people have an uncontrollable desire to sleep or may suddenly fall into a deep sleep, may also be helped by CNS stimulants. The medication is prescribed in an effort to reduce the frequency and severity of attacks of narcolepsy. Caffeine may be used as a mild CNS cerebral stimulant to cause the patient to stay awake. Other CNS medications used for narcolepsy include, amphetamine sulfate, methamphetamine hydrochloride, and methlyphenidatehydrochloride (Ritalin).
Central nervous system stimulants should never be used to increase alertnessor as a substitute for sleep. Although they can cause loss of appetite and weight loss, they should not be used as "diet pills." Medical use of the drug methamphetamine (Speed) as an appetite suppressant is strictly for treating obesity, or in treating anesthetic overdose. The drug amphetamine should be avoided by persons with hypertension and cardiovascular disease, and by those who are extremely restless, anxious, agitated, and excited.
Always take CNS stimulants exactly as directed. Never take larger or more frequent doses, and do not take the drug for longer than directed. This medicinemay be habit forming if taken in large doses or over long periods. If it isnecessary to stop taking the drug, check with the doctor who prescribed it for instructions on how to stop. The body may take several weeks to adjust after treatment of a CNS stimulant has stopped.
Some people feel drowsy, dizzy, lightheaded, or less alert when using these drugs. The drugs may also give some people a false sense of well being. Because of these possible effects, anyone who takes these drugs should not drive, use machines, or do anything else that might be dangerous until they have found out how the drugs affect them.
The most common side effects of CNS stimulants are irritability, nervousness,restlessness, loss of appetite, sleep problems, and a false sense of well being. After these effects wear off, other effects may occur, such as trembling, drowsiness, unusual tiredness or weakness, or depression. These side effects and after effects usually go away as the body adjusts to the drug and do not require medical treatment unless they continue, or they interfere with normal activities.
More serious side effects may occur from CNS stimulants. If chest pain, irregular heartbeat, breathing problems, dizziness, faintness, extreme fatigue, weakness, high fever, hives, vomiting, convulsions, involuntary movement, or arise in blood pressure occur, check with the doctor who prescribed the medicine as soon as possible.
CNS stimulants may cause physical or mental dependence when taken over long periods. Anyone who shows signs of dependence should check with his or her doctor right away. Dependence can be indicated by an unusually strong desire tokeep taking the medicine. Other signs include the need to take larger and larger doses of the medicine to get the same effect, and withdrawal symptoms, such as depression, nausea or vomiting, stomach cramps or pain, trembling, or unusual tiredness or weakness when the medicine is stopped. Studies have shownthat dependence of a central nervous system stimulant is directly proportional to its stimulation effect. The central nervous system stimulant medications that are most likely to lead to dependence are as follows (in descending order from most likely to least likely): amphetamine; methamphetamine; dextroamphetamine; phenmetrazine; phentermine; phendimetrazine; mazindol, diethylpropion; and fenfluramine.
One of the most commonly abused CNS stimulants is cocaine (also known as a psychomotor stimulant). This potent CNS stimulant is use therapeutically as a local anaesthetic. Cocaine produces stimulant effects such as euphoria and a feeling of increased energy, similar to the effect of amphetamines, in addition to the development of the similar psychotic state with strong circumstancesof paranoia. Known as a social-recreational drug, cocaine displays strong characteristics of both physical and psychological dependence. Initial symptomswhen using the drug include restlessness, hypertension, and hallucinations.Chronic abusers may experience a toxic cocaine psychosis (similar to paranoidschizophrenia) identified by hallucinations and paranoid delusions, in addition to self-inflicted skin eruptions caused by itching and compulsive scratching. A large dose of cocaine is directly linked to cardiotoxicity (causing apoisonous effect on the heart), while death from overdose may result from respiratory failure.
Because of their high potential for abuse, sale of the CNS stimulants amphetamines and methylphenidates is strictly controlled by the U.S. Drug Enforcement Administration (DEA). Prescriptions cannot be refilled, and patients must get a new prescription from the doctor each time they need a new supply of medicine.
Before using central nervous system stimulants, people with any of these medical conditions should inform their doctors: pregnancy, due to an increased risk of birth defects, premature delivery, or delivering a low birth weight baby from use of CNS stimulants; allergies to medications, foods, dyes, preservatives, or other substances; current or past alcohol or drug abuse; psychosisor other severe mental illness; severe anxiety, tension, agitation, or depression; seizure disorders, such as epilepsy; heart or blood vessel disease; high blood pressure; overactive thyroid; glaucoma; and Tourette's syndrome or other tics.
Some central nervous system stimulants pass into breast milk. Breastfeeding is not recommended while taking these drugs. Women who want to breastfeed their babies should check with their doctors before using any central nervous system stimulant.
Taking central nervous system stimulants with certain other drugs may affectthe way the drugs work or may increase the chance of side effects. Be sure tocheck with a doctor or pharmacist before combining central nervous stimulants with any other prescription or nonprescription (over-the-counter) medicine.