ADHD medications

Types and differences of ADHD medications

The four major categories of drugs used to treat attention deficit hyperactivity disorder (ADHD) are psychostimulants, alpha-2 adrenergic agonists, antidepressants and norepinephrine reuptake inhibitors.

Psychostimulants, often simply referred to as “stimulants,” inhibit the reabsorption of dopamine, a neurotransmitter that helps to keep the central nervous system (CNS) functioning normally. This leaves more dopamine circulating in the body. Stimulants are the mainstay of ADHD medication treatment, and up to 90 percent of patients who take them report at least some improvement in symptoms such as impulsivity and hyperactivity, according to the American Psychiatric Association (APA). Although these drugs have a stimulating effect on most people, they are calming in patients with ADHD.

Stimulants usually work fairly rapidly, with symptom reduction beginning between 30 and 45 minutes after ingestion. They work for between 4 and 12 hours and are typically taken two to three times daily. Some longer-acting (extended release) formulations may be taken just once a day. Most of the stimulants are only recommended for children over age 6. However, some amphetamines may be prescribed to children over age 3. The stimulant pemoline is no longer used to treat ADHD because it may cause serious side effects that may harm the liver. It was withdrawn from the market in 2005.

Alpha-2 adrenergic agonists are sometimes used to treat core ADHD symptoms, but more often are used to reduce irritability and aggression related to ADHD. They can also be used to promote sleep in patients who report insomnia.

Depression is a disorder commonly associated with ADHD, and antidepressants are often prescribed to treat lasting feelings of sadness. In addition, antidepressants that increase the availability of the neurotransmitters dopamine and norepinephrine in the body appear to be effective in treating core symptoms of ADHD. The tricylcic antidepressants and the dopamine-norepinephrine reuptake inhibitor bupropion appear to be particularly effective in treating ADHD. The drug atomoxetine is technically an antidepressant approved to treat ADHD, although it is not approved to treat depression. Many of the other non-stimulant medication used for ADHD are approved for other purposes, such as treating depression and high blood pressure. They are prescribed for patients with ADHD as part of the common practice of “off-label” prescriptions.

Antidepressants are sometimes used to treat ADHD in patients who do not tolerate stimulants well. These drugs only have to be taken once daily. They are prescribed far more often in adults than in children. Selective serotonin reuptake inhibitors (SSRIs), often used to treat depression and anxiety, have not been effective in treating the symptoms of ADHD.

Patients should be aware that a physician may need to adjust the dosage or change medications to achieve the best results with minimal side effects. In addition, the U.S. Food and Drug Administration (FDA) has advised that antidepressants may increase the risk of suicidal thinking in some patients and all people being treated with them should be monitored closely for unusual changes in behavior.

Conditions of concern with ADHD medications

The presence of other medical conditions does not necessarily prohibit the use of ADHD medications. However, individuals should always inform their physician of any existing medical conditions and work closely with their physician to design a treatment plan that meets their unique needs. Many children with ADHD typically have other conditions, some of which require medication.

Stimulants are usually well-tolerated by patients with ADHD and are rarely abused. However, patients with anxiety disorders should take these medications cautiously, as they aggravate the condition. Usually, a physician will choose to treat and control an anxiety disorder before using stimulants to treat attention deficit hyperactivity disorder (ADHD).

Stimulants should only be used with caution in patients who have a history of seizures, drug and alcohol abuse, kidney disease, high blood pressure (hypertension) or EEG (brain electricity) abnormalities. Patients with diabetes may have to alter insulin intake while using stimulant drugs.

One stimulant in particular, dextroamphetamine (Dexedrine), has been linked to sudden death in children and teenagers with certain heart problems. U.S. officials have asked the drug’s manufacturer to add a label reflecting this risk to the drug’s packaging. In 2008, the American Heart Association recommended that children should receive cardiac screening, including heart rate, blood pressure check and electrocardiogram (EKG), before they start taking stimulants for ADHD.

Other conditions of concern that may prohibit the use of stimulants include:

• Glaucoma (disease that results in increased pressure in the eye)
• Hypertension (high blood pressure)
• Hyperthyroidism (excessive production of thyroid gland)
• Liver disease
• Motor tics
• Tourette’s syndrome (or family history of this disease)

Conditions of concern for patients taking antidepressants other than bupropion (Wellbutrin) to treat ADHD include:

• Cardiovascular disease
• Certain blood disorders
• Glaucoma
• Hypertension
• Liver or kidney disease
• Tachycardia (rapid heart rate)

Bupropion poses an increased risk of seizures. Therefore, individuals with seizure disorders may benefit from an alternative medication.

Conditions of concerns for patients taking norepinephrine reuptake inhibitors to treat ADHD include:

• Cardiovascular disease
• Hypertension
• Liver or kidney disease
• Tachycardia
• Cardiovascular disease
• Liver or kidney disease

Conditions of concern for patients taking alpha-2 adrenergic agonists to treat ADHD include:

• Cardiovascular disease and other heart problems
• Depression
• Diabetes mellitus
• Liver or kidney disorders

It is important to note that these conditions do not prohibit the use of the alpha-2 adrenergic agonists.

Potential side effects of ADHD medications

In the past, some healthcare providers have been reluctant to use medications such as stimulants to treat attention deficit hyperactivity disorder (ADHD) for fear that the patient would become dependent on the drug. However, these fears are largely unfounded. When taken at proper dosage levels, stimulants rise too slowly in the brain to cause the patient to feel “high.” Nonetheless, the number of people who abuse these drugs and use them illicitly appears to be growing.

Some children who take stimulant medications report feeling slightly “funny” or different when taking the drugs. However, this effect is usually minor. Some children may experience rebounding of their ADHD symptoms, such as irritability when the medication is wearing off. Doses or timing can be adjusted to alleviate this effect.

Recent research also indicates that use of stimulants can suppress a child’s growth, although the average growth suppression found in children taking stimulants for the disorder is minimal.

Other side effects associated with stimulant use include insomnia, loss of appetite, stomachache, dysphoria (condition marked by anxiety, depression and restlessness), lethargy, sedation and/or impaired concentration. In rare cases, stimulant drugs may cause a child to develop a tic. This is typically resolved by changing the child’s dosage level.

Adults who take stimulant drugs may experience mild increases in blood pressure. This can be a significant development for adults who have high blood pressure (hypertension) or liver disease including hepatitis. The risk of abuse is also higher in adults than in children, as adults need to take larger amounts of the drug in order for it to be effective.

Side effects associated with antidepressants taken to treat ADHD may include dry mouth, urinary retention, nausea, weight gain or loss, drowsiness and sexual dysfunction in adults, depending upon which antidepressant is used.

In addition, the U.S. Food and Drug Administration (FDA) has advised that antidepressants, including those used to treat ADHD, may increase the risk of suicidal thinking in some patients and all people being treated with them should be monitored closely for unusual changes in behavior.

Side effects associated with the alpha-2 adrenergic agonists include sedation, depression, and dry mouth. An increase in blood pressure (hypertension) may occur after use of these medications is discontinued.

Drug or other interactions

Patients who take drugs to treat attention deficit hyperactivity disorder (ADHD) should consult their physicians before taking any additional prescriptions, over-the-counter medications, nutritional supplements or herbal medications.

Stimulant drugs and alpha-2 adrenergic agonists are often combined to treat ADHD. There have been a handful of reported deaths in children who have taken this combination. However, an investigation by the U.S. Food and Drug Administration (FDA) found no significant danger in taking these drugs together.

Caffeine use can decrease the effectiveness of stimulants in treating ADHD. In addition, use of the antidepressant MAO inhibitors (MAOIs) with stimulants can cause severe high blood pressure (hypertension). Vitamin C supplements (ascorbic acid) may shorten the duration of the dosage.

Other drugs that may interact poorly with stimulants include:

• Antacids
• Anticonvulsants
• Anticoagulants (drugs that help prevent blood clots)
• Antidepressants (in addition to MAO inhibitors)
• Antipsychotics
• Bretylium tosylate (heart drug)
• Sedatives such as barbiturates

Drugs that may interact poorly with antidepressants used to treat ADHD include:

• Other antidepressants
• Certain blood pressure medications
• Sedatives such as benzodiazepines

Drugs that may interact poorly with alpha-2 adrenergic agonists used to treat ADHD include:

• Antidepressants
• Antihypertensives
• Central nervous system (CNS) depressants such as alcohol and sedatives
• Nonsteroidal anti-inflammatory drugs (NSAIDs)

Symptoms of ADHD medication overdose

Symptoms of overdose can be similar to the medication’s side effects, but are usually more severe. Patients exhibiting any of these symptoms while taking stimulants should contact their physician immediately:

• Agitation
• Confusion
• Delirium
• Dry mouth
• Euphoria
• Fever
• Flushing
• Headache
• Hallucinations
• Heart palpitations
• Nausea and vomiting
• Seizures

Symptoms of overdose with antidepressants used to treat ADHD include:

• Ataxia (disorder that affects many tissues and body systems)
• Seizures

Symptoms of overdose associated with alpha-2 adrenergic agonists used to treat ADHD include:

• Hypotension (low blood pressure)
• Breathing difficultes
• Hypothermia (low body temperature)
• Apnea (cessation of breathing)
• Seizures
• Lethargy
• Agitation
• Irritability
• Diarrhea
• Slow heartbeat
• Unusual tiredness or weakness

Pregnancy use issues with ADHD medications

Women who are pregnant, thinking of becoming pregnant or who are breastfeeding should not use ADHD medications before discussing the potential advantages and disadvantages of such use with a physician. It is unknown whether some ADHD medications are potentially harmful to fetuses or nursing infants, but many experts advise against using these drugs during pregnancy or breastfeeding.

Child use issues

The safety of many ADHD medications has not been established in children. In many cases, these drugs are not recommended for use in children under the age of 6. Some stimulant medications have been associated with growth suppression in children.

In addition, the U.S. Food and Drug Administration (FDA) has warned that some children and adolescents who use antidepressants and norepinephrine reuptake inhibitors may experience thoughts of suicide. Although this is rare, it has led experts to urge that children who take antidepressants for ADHD be closely observed for signs of agitation, irritability and unusual changes in behavior. The major drugs in these classes are required to display the so-called “black box” warning labels that indicate the potential for suicidal thoughts and behaviors.

Stimulant ADHD medications can be abused and misused when they are taken in higher than prescribed dosages. Parents may want to administer the medication to their children to ensure it is taken as prescribed. Many school districts require that their personnel administer any medication taken during school hours. Despite the potential for abuse of ADHD drugs, recent studies show that correct use of psychostimulant medication for ADHD in children and adolescents does not increase the risk of substance abuse in later life.

Elderly use issues

Dosage levels of some ADHD medications may need to be reduced for elderly patients. In addition, elderly patients may experience additional side effects when taking some ADHD medications. For example, elderly patients who take the alpha-2 adrenergic agonist guanfacine hydrochloride may experience dizziness, drowsiness, hypotension (low blood pressure) and/or faintness.