Desoxyn

Definition

Central nervous system (CNS) stimulants are medicines that speed up physical and mental processes.

Purpose

Central nervous system stimulants, such as amphetamines and methylphenidate (Ritalin), are used to treat attention-deficit hyperactivity disorder (ADHD), a condition in which people have unusually high activity levels and short attention spans. People with this condition are easily distracted and may have trouble sitting still, planning ahead, or finishing what they start. They may also act recklessly and impulsively, and have behavioral and emotional problems. Central nervous system stimulants increase attention, decrease restlessness, and improve physical coordination in people who have ADHD. The drugs may also curb impulsive behavior. When used to treat ADHD, central nervous system stimulants are just one part of the total treatment program, which also includes social, educational, and psychological help.

Although central nervous system stimulants are effective in treating ADHD, their use is controversial, especially in children. Because they may cause unwanted side effects, parents and doctors of children who need the drugs must carefully weigh the risks and benefits. There is also concern that these drugs are being prescribed for some children who do not need them. Other physical and mental conditions can have some of the same symptoms as ADHD, so it is important to rule out other causes before starting treatment with central nervous system stimulants.

This type of medicine is also used to treat narcolepsy, in which people have an uncontrollable desire to sleep or may suddenly fall into a deep sleep. The medication is prescribed in an effort to reduce the frequency and severity of attacks of narcolepsy.

Central nervous system stimulants should not be used to increase alertness or to substitute for sleep. Although they can cause loss of appetite and weight loss, they should not be used as "diet pills."

Description

Commonly used central nervous system stimulants are amphetamine, dextroamphetamine (Dexedrine, DextroStat), methamphetamine (Desoxyn), pemoline (Cylert), and methylphenidate (Ritalin).

Amphetamines and methylphenidate are available only with a doctor's prescription. Because of their high potential for abuse, sale of these drugs is strictly controlled. Prescriptions cannot be refilled. Patients must get a new prescription from the doctor each time they need a new supply of medicine.

Recommended dosage

The recommended dosage depends on the type of central nervous system stimulant and the condition for which it is being prescribed. Check with the doctor who prescribed the drug or the pharmacist who filled the prescription for the correct dosage.

Always take central nervous system stimulants exactly as directed. Never take larger or more frequent doses, and do not take the drug for longer than directed. This medicine may be habit forming if taken in large doses or over long periods.

Be sure to follow directions for when to take the medicine. Some forms of central nervous system stimulants should not be taken too close to bedtime, for example, because they will interfere with sleep.

It may take several weeks for the effects of this medicine to be felt. Be sure to keep taking it as directed, even if it doesn't seem to be helping.

Do not stop taking this medicine suddenly after taking it for several weeks or more. It may be necessary to taper down gradually. If it is necessary to stop taking the drug, check with the doctor who prescribed it for instructions on how to stop.

Precautions

It is important to see a doctor regularly while taking central nervous system stimulants. The doctor will check to make sure the medicine is working as it should and will watch for unwanted side effects.

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.

Central nervous system stimulants may change the results of certain medical tests. Before having medical tests, anyone taking this medicine should alert the health care professional in charge.

These drugs may cause physical or mental dependence when taken over long periods. Anyone who shows these signs of dependence should check with his or her doctor right away:

• The need to take larger and larger doses of the medicine to get the same effect
• A strong desire to keep taking the medicine
• Withdrawal symptoms, such as depression, nausea or vomiting, stomach cramps or pain, trembling, or unusual tiredness or weakness when the medicine is stopped.

When used over long periods in children, central nervous system stimulants may interfere with growth and cause unwanted behavioral effects. Parents whose children need to take these drugs should thoroughly discuss the risks and benefits with the child's doctor. The doctor may recommend periodic "drug holidays," during which time the child stops taking the medicine.

Children may be more sensitive than adults to the effects of methylphenidate. This sensitivity may increase the chances of unwanted side effects, such as loss of appetite, stomach pain, sleep problems, and weight loss.

Special conditions

People with certain medical conditions or who are taking certain other medicines can have problems if they take central nervous system stimulants. Before taking these drugs, be sure to let the doctor know about any of these conditions:

Anyone who has had unusual reactions to amphetamine, dextroamphetamine, ephedrine, epinephrine, isoproterenol, metaproterenol, methamphetamine, norepinephrine, phenylephrine, phenylpropanolamine, pseudoephedrine, terbutaline, or methylphenidate in the past should let his or her doctor know before taking a central nervous system stimulant. The doctor should also be told about any allergies to foods, dyes, preservatives, or other substances.

Pregnancy

The effects of taking central nervous system stimulants during pregnancy have not been studied in humans. However, animal studies show that taking amphetamines early in pregnancy may increase the chance of birth defects. Overuse of amphetamines during pregnancy may also increase the risk of premature delivery or having a baby with a low birth weight. Babies whose mothers use these drugs during pregnancy may also become dependent on the drugs and may have withdrawal symptoms after birth. Women who are pregnant or who may become pregnant should check with their doctors before using central nervous system stimulants.

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.

Before using central nervous system stimulants, people with any of these medical problems should make sure their doctors are aware of their conditions:

• Current or past alcohol or drug abuse
• Psychosis or 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
• Tourette's syndrome or other tics.

Taking central nervous system stimulants with certain other drugs may affect the way the drugs work or may increase the chance of side effects.

Side effects

The most common side effects 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. If any of the following side effects occur, check with the doctor who prescribed the medicine as soon as possible:

• Irregular or pounding heartbeat
• Chest pain
• Higher than normal blood pressure
• Breathing problems
• Dizziness or faintness
• Unusual tiredness or weakness
• High fever
• Skin rash or hives
• Involuntary movements of the head, neck, arms, and legs
• Mood or mental changes.

It may take several weeks for the body to adjust after treatment with this medicine has ended. Side effects may occur during this period. Check with a doctor if any of these side effects occur after stopping treatment with a central nervous system stimulant:

• Nausea or vomiting
• Stomach pain or cramps
• Trembling
• Unusual tiredness or weakness
• Depression.

Other side effects are possible with central nervous system stimulants. Anyone who has unusual symptoms during or after treatment with these drugs should get in touch with his or her doctor.

Interactions

Central nervous system stimulants may interact with many other medicines. When this happens, the effects of one or both of the drugs may change or the risk of side effects may be greater. Anyone who takes central nervous system stimulants should let the doctor know all other medicines he or she is taking. Among the drugs that may interact with central nervous system stimulants are:

• Other central nervous system stimulants
• Caffeine
• Diet pills (appetite suppressants)
• Cocaine
• Betablockers such as Tenormin, Inderal, and Lopressor
• Monoamine oxidase inhibitors (MAO) such as Nardil or Parnate, used to treat conditions including depression and Parkinson's disease
• Tricyclic antidepressants such as imipramine (Tofranil) or desipramine (Norpramin)
• Thyroid hormones
• Digitalis heart medicines
• Medicine for colds, sinus problems, hay fever, asthma, or other allergies or breathing problems (including nose drops or sprays)
• Amantadine (Symmetrel), used to treat flu and Parkinson's disease
• Cesamet, used to prevent nausea and vomiting after treatment with anticancer drugs
• Orap, used to treat Tourette syndrome
• The cough medicine Ulone.

The list above may not include every drug that interacts with central nervous system stimulants. Be sure to check with a doctor or pharmacist before combining central nervous stimulants with any other prescription or nonprescription (over-the-counter) medicine.

Key Terms

Anxiety

Worry or tension in response to real or imagined stress, danger, or dreaded situations. Physical reactions, such as fast pulse, sweating, trembling, fatigue, and weakness may accompany anxiety.

Attention-deficit hyperactivity disorder (ADHD)

A condition in which a person has an unusually high activity level and a short attention span. People with the disorder may act impulsively and may have learning and behavioral problems.

Central nervous system

The brain and spinal cord.

Depression

A mental condition in which people feel extremely sad and lose interest in life. People with depression may also have sleep problems and loss of appetite, and may have trouble in concentrating and carrying out everyday activities.

Tourette's syndrome

A condition in which a person has tics and other involuntary behavior, such as barking, sniffing, swearing, grunting, and making unnecessary movements.

Withdrawal symptoms

A group of physical or mental symptoms that may occur when a person suddenly stops using a drug on which he or she has become dependent.

Further Reading

For Your Information

Periodicals

• "Are our children overmedicated?" Parade, (October 12, 1997): 4.
• "Attention deficit hyperactivity disorder: not just for kids." Mayo Clinic Health Letter, 13 (September 1995): 6.
• "Attention deficit hyperactivity disorder: there is no easy answer on whether to medicate or not." British Medical Journal, 315 (October 11, 1997): 894.
• "The run on Ritalin: attention deficit disorder and stimulant treatment in the 1990s." The Hastings Center Report, 26 (March-April 1996): 12.

  Organizations

• Children and Adults with Attention Deficit Disorders (CH.A.D.D.). 499 N.W. 70th Avenue, Suite 109, Plantation, FL 33317. (305) 587-3700.

  Other

• Attention deficit hyperactivity disorder Pamphlet. National Institute of Mental Health, 1994.
• Facts about childhood hyperactivity Pamphlet. National Institute of Child Health and Human Development, 1990.

Gale Encyclopedia of Medicine. Gale Research, 1999.