Children with attention-deficit/hyperactivity disorder (ADHD) are mainly cared for in primary care settings by us. Management of this chronic neurodevelopmental condition that affects 5+% of children worldwide should include proper diagnosis, assessment for contributing and comorbid conditions, behavioral intervention (the primary treatment for preschoolers), ensuring good sleep and nutrition, and usually medication.
Because stimulants are very effective for reducing ADHD symptoms, we may readily begin these first-line medications even on the initial visit when the diagnosis is determined. But are we really thoughtful about knowing and explaining the potential short- and long-term side effects of these medications that may then be used for many years? Considerable discussion with the child and parents may be needed to address their concerns, balanced with benefits, and to make a plan for their access and use of stimulants (and other medications for ADHD not the topic here).
Dr. Barbara J. Howard
Consider the Side Effects
In children older than 6 years, some form of either a methylphenidate (MPH) or a dextroamphetamine (DA) class of stimulant have been shown to be equally effective in reducing symptoms of ADHD in about 77% of cases, but side effects are common, mostly mild, and mostly in the first months of use. These include reduced appetite, abdominal pain, headache, weight loss, tics, jitteriness, and delays in falling asleep. About half of all children treated will have one of these adverse effects over 5 years, with reduced appetite the most common. There is no difference in effectiveness or side effects by presentation type, i.e. hyperactive, inattentive, or combined, but the DA forms are associated with more side effects than MPH (10% vs. 6%). Medicated preschoolers have more and different side effects which, in addition to those above, may include listlessness, social withdrawal, and repetitive movements. Fortunately, we can reassure families that side effects can usually be readily managed by slower ramp up of dose, spacing to ensure appetite for meals, extra snacks, attention to bowel patterns and bedtime routines, or change in medication class.
Rates of tics while on stimulants are low irrespective of whether DA or MPH is used, and are usually transient, but difficult cases may occur, sometimes as part of Tourette’s, although not a contraindication. Additional side effects of concern are anxiety, irritability, sadness, and overfocusing that may require a change in class of stimulant or to a nonstimulant. Keep in mind that these symptoms may represent comorbid conditions to ADHD, warranting counseling intervention rather than being a medication side effect. Both initial assessment for ADHD and monitoring should look for comorbidities whether medication is used or not.
Measuring height, weight, pulse, and blood pressure should be part of ADHD care. How concerned should you and the family be about variations? Growth rate declines are more common in preschool children; in the PATS study height varied by 20.3%, and weight by 55.2%, more in heavier children. Growth can be protected by providing favored food for school, encouraging eating when hungry, and an evening fourth meal. You can reassure families that, even with continual use of stimulant medicines for years and initial deficits of 2 cm and 2.7 kg compared to expected, no significant differences remain in adulthood.
This longitudinal growth data was collected when short-acting stimulants were the usual, rather than the now common long-acting stimulants given 7 days per week, however. Children on transdermal MPH with 12-hour release over 3 years showed a small but significant delay in growth with the mean deficit rates 1.3 kg/year mainly in the first year, and 0.68 cm/year in height in the second year. If we see growth not recovering as it is expected to after the first year of treatment, we can advise shorter-acting forms, and medication “holidays” on weekends or vacations, that reduce but do not end the deficits. When concerned, a nonstimulant can be selected.
Blood pressure and pulse rate are predictably slightly increased on stimulants (about 2-4 mm Hg and about 3-6 bpm) but not clinically significantly. Although ECGs are not routinely recommended, careful consideration and consultation is warranted before starting stimulants for any patient with structural cardiac abnormalities, unexplained syncope, exertional chest pain, or a family history of sudden death in children or young adults. Neither current nor former users of stimulants for ADHD were found to have greater rates of cardiac events than the general population, however.