Drugs for attention deficit hyperactivity disorder (ADHD)

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Introduction

The diagnosis of ADHD is controversial, and so is the treatment. If you or your child have been diagnosed with attention deficit hyperactivity disorder (ADHD), you/they may have been offered a drug treatment. This factsheet is for people who wish to know more about the drugs that are sometimes used when ADHD is diagnosed. For more information about ADHD, see Mind's booklet Understanding attention deficit hyperactivity disorder.

Background to the drugs used for ADHD

Stimulant drugs (amphetamines) have been used to treat ADHD since 1937. Studies show that they decrease physical activity and increase alertness, and improve performance in learning tasks in all groups. Recently, non-stimulant drugs have also been developed for this condition.

There are three drugs which are licensed for the treatment of ADHD in the UK. All three are to be prescribed only under the supervision of a specialist experienced in managing ADHD. The National Institute for Health and Clinical Excellence (NICE) recommends that they should be used only in conjunction with social, behavioural and psychological treatments.

The way these drugs work in ADHD is not known, and the long-term effects of all of these drugs are not known.

Stimulant drugs

Methylphenidate and dexamfetamine are stimulant drugs in the class that includes amphetamines (amfetamines) and they act in a similar way to cocaine, increasing activity in the parts of the brain that control attention. The chemistry is different from cocaine in a way which makes these drugs less likely to become addictive. However, the British National Formulary recommends that amphetamines have a very limited field of usefulness, and their use should be discouraged as they may cause dependence and psychotic states. They are Schedule II controlled drugs – in the same category as barbiturates and methadone.

In February 2006, the drug safety and risk committee of the Food and Drug Administration (FDA) in America recommended that ADHD stimulant treatments should carry a 'black box' warning of the risk of sudden death, following a report listing 25 sudden deaths in both adults and children, between 1999 and 2003. Some of the patients had known heart disease, and the cautions for these drugs do include heart disease (see below).

Methylphenidate (trade names Ritalin, Concerta XL, Equasym, and Equasym XL)

This drug is licensed for the treatment of ADHD when behavioural measures alone are not enough. It comes in tablet and capsule form.

Ritalin tablets contain a 10mg dose.

Concerta XL tablets contain either 18mg or 38mg, in a modified release formulation, which means that the drug is active over a longer period than Ritalin. A total daily dose of 15mg of the normal release formulation (standard form) is considered equivalent to 18mg daily of the Concerta XL modified release formulation.

Equasym tablets contain doses of 5, 10 and 20mg.

Equasym XL capsules contain doses of 10, 20 and 30mg, in a modified release formulation.

When not to use methylphenidate
Methylphenidate should not be given to people with anxiety or agitation; tics or a family history of Tourette's syndrome; an overactive thyroid; severe angina (heart pain) or irregular heart beat; glaucoma (an eye disease); or while breast-feeding.

Cautions
Growth should be monitored if the drug is taken for a long time; blood pressure and blood cell counts should be checked. It should be used with caution in people with a history of drug or alcohol dependence; psychosis; epilepsy (discontinue if fits occur more frequently); and in pregnancy. Withdraw slowly.

Side effects of methylphenidate
Abdominal pain, feeling or being sick, dry mouth; fast heart rate, palpitations, irregular heart beat, changes in blood pressure; insomnia, nervousness, loss of appetite, headache, drowsiness, dizziness, movement disorders; painful joints; rashes, itching, hair loss; rarely, inflammation of blood vessels in the brain, angina (heart pain), hyperactivity, fits, psychosis, tics including Tourette's syndrome, neuroleptic malignant syndrome (a serious condition more commonly associated with antipsychotic drugs, involving high fever, tremor and rigidity and changes in consciousness), becoming dependent on the drug, growth retardation, reduced weight gain, blood disorders, muscle cramps, visual disturbances, peeling skin, erythema multiforme (raised red patches on the skin),

The modified release form may pass through the gut without being broken down, and is not appropriate for people with recurrent indigestion or people with a narrowed gut.

Dose
Normal release formulation for children over six years: initially 5mg once or twice/day, increased if necessary at weekly intervals by 5-10mg/day to a maximum dose of 60mg/day, in two or more doses.

Modified release formulation for children over the age of six years: initially 18mg/day in the morning, increased if necessary in weekly steps of 18mg to a maximum of 54mg/day.

For both forms, if there is no response after one month it should be stopped. It should also be stopped periodically to assess the child, and is usually stopped completely at puberty. It is not recommended for children under the age of six years.


Dexamfetamine (dexamphetamine) (trade name Dexedrine)

This drug can be used, under specialist supervision, to treat ADHD in children where other medication is not adequate to control the condition. It comes in tablet form. Each tablet contains 5mg.

When not to use dexamfetamine
It should not be given to people with moderate to severe high blood pressure or heart disease, excitability or agitation; an overactive thyroid; glaucoma (an eye disease); a history of drug or alcohol abuse; or during pregnancy or breast-feeding.

Cautions
This should be used with caution in people with slightly raised blood pressure, epilepsy (stop if fits occur); tics and Tourette's syndrome (stop if tics occur). Children's growth should be monitored as it may slow growth. It can be withdrawn for periods to allow growth to catch up, but it should not be stopped abruptly, as it may induce depression or renewed hyperactivity. It may increase behavioural disturbances and thought disorder in children with a diagnosis of psychosis.
 
Side effects of dexamfetamine
Sleeplessness, restlessness, irritability and excitability, nervousness, night terrors, euphoria, shaking, dizziness, headache, fits; becoming dependent on the drug; sometimes psychosis, loss of appetite, gastro-intestinal symptoms, slowed growth in children, dry mouth, sweating, fast heart beat, palpitations, raised blood pressure, visual disturbances; heart muscle problems with long-term use, movement disorders, tics and Tourette's syndrome.

Dose
Children over six years: 5-10mg/day, increased if necessary by 5mg/week to maximum dose 20mg/day. Older children have received a maximum of 40mg/day. NICE suggests it may be used for children over three years old, but there are no dosage guidelines in the British National Formulary for children under six.

Non-stimulant drugs

Atomoxetine (trade name Strattera)

Atomoxetine is not a stimulant, but its effects on the brain are similar to those of stimulant drugs, and it is less likely to be addictive or to become a drug of abuse.

This drug is licensed for the treatment of ADHD in children and adults. Treatment should be started by a specialist, but may be continued by a GP. It comes in capsule form. The smallest available dose is 10mg, and the largest 60mg.

When not to use atomoxetine
It should not be given to people with closed-angle glaucoma (an eye disease).

Cautions
Atomoxetine should be used with caution in people with diseases of the heart or blood vessels, including fast heart rate and low blood pressure on standing up. It may slow growth in children so this should be monitored. It should be used with caution during pregnancy and while breast-feeding, and in people with liver disease. Because a few people have developed liver disease while taking this drug, you should be told how to recognise symptoms, and see a doctor promptly in any case of stomach pain, unexplained nausea (feeling sick), feeling unwell, dark urine, or jaundice (yellow skin).

Side effects of atomoxetine
Commonest first: loss of appetite, dry mouth, feeling or being sick, abdominal pain, constipation, indigestion, wind, palpitations, fast heart rate, raised blood pressure, low blood pressure when you stand up, hot flushes, disturbed sleep, dizziness, headache, tiredness, lack of energy, depression, anxiety, irritability, shaking, stiffness, difficulty urinating, bed-wetting, inflammation of the prostate gland, sexual problems, menstrual disturbances, dilated pupils, conjunctivitis, inflammation of the skin, itching, rashes, sweating weight changes; less commonly, cold hands and feet; very rarely, liver problems and suicidal thoughts.

In September 2005, the Committee on Safety of Medicines in the UK published a warning about an increase in suicidal thoughts and behaviour in children aged 7-12 years taking Strattera. Up to 15,000 patients have been treated with the drug in the UK since it was first marketed in July 2004. There have been 169 yellow card reports of adverse reactions, of which 11 included suicidal thoughts or behaviour.

Dose
Adolescents weighing over 70kg and adults: 40mg/day for seven days, then increased according to response to usual maintenance dose of 80mg/day.
Maximum dose 100mg/day.

Children over six years and adolescents weighing up to 70kg: 500mcg/kg/day for seven days, increased according to response to usual maintenance dose 1.2mg/kg/day. Maximum dose: 1.8mg/kg/day.

For example, for a child weighing 30kg, the starting dose would be 500mcg (0.5mg) X 30 = 15mg/day; the usual maintenance dose would be 1.2 X 30 = 36mg/day; the maximum dose would be 1.8 X 30 = 54mg/day.
 
The total daily dose should be given either all at once in the morning, or in two doses, with the second given no later than early evening.

References

British National Formulary (BNF) 51, March 2006.
Electronic medicines compendium, http://emc.medicines.org.uk
NICE, 2006, Methylphenidate, atomoxetine and dexamfetamine for attention deficit hyperactivity disorder (ADHD) in children and adolescents. Technology appraisal 98.
'FDA panel proposes black box warning for ADHD stimulants', www.scripnews.com, No. 3131, 15 February 2006.
'Updated warnings on the attention deficit hyperactivity disorder drug Strattera – information for healthcare professionals', Medicines and Healthcare products Regulatory Agency, www.mhra.gov.uk, 16 February 2006.
Bailly, L. 2005, 'Stimulant medication for the treatment of attention-deficit hyperactivity disorder: evidence-b(i)ased practice?', Psychiatric Bulletin, vol 29, pp 284-287.

Useful organisations

ADDISS
tel: 020 8906 9068
web: www.addiss.co.uk
The national attention deficit hyperactivity disorder information and support service.

Psychiatric drugs helpline
tel: 020 7919 2999 (Mon to Fri 11am to 5pm)

Further reading

Understanding attention deficit hyperactivity disorder (Mind 2006)
Understanding childhood distress (Mind 2004)

This factsheet was written by Katherine Darton, Mind Information Unit, April 2006.