Stimulant Medications for ADHD — the Good, the Bad, and the Ugly

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.

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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).

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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 the 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.

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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.

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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.

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Misuse and abuse

Misuse and diversion of stimulants is common (e.g. 26% diverted MPH in the past month; 14% of 12th graders divert DA), often undetected, and potentially dangerous. And the problem is not limited to just the kids. Sixteen percent of parents reported diversion of stimulant medication to another household member, mainly to themselves. Stimulant overdose can occur, especially taken parenterally, and presents with dilated pupils, tremor, agitation, hyperreflexia, combative behavior, confusion, hallucinations, delirium, anxiety, paranoia, movement disorders, and/or seizures. Fortunately, overdose of prescribed stimulants is rarely fatal if medically managed, but recent “fake” Adderall (not from pharmacies) has been circulating. These fake drugs may contain lethal amounts of fentanyl or methamphetamine. Point out to families that a peer-provided stimulant not prescribed for them may have underlying medical or psychiatric issues that increase adverse events. Selling stimulants can have serious legal implications, with punishments ranging from fines to incarceration. A record of arrest during adolescence increases the likelihood of high school dropout, lack of 4-year college education, and later employment barriers. Besides these serious outcomes, it is useful to remind patients that if they deviate from your recommended dosing that you, and others, will not prescribe for them in the future the medication that has been supporting their successful functioning.

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You can be fooled about being able to tell if your patients are misusing or diverting the stimulants you prescribe. Most (59%) physicians suspect that more than one of their patients with ADHD has diverted or feigned symptoms (66%) to get a prescription. Women were less likely to suspect their patients than are men, though, so be vigilant! Child psychiatrists had the highest suspicion with their greater proportion of patients with ADHD plus conduct or substance use disorder, who account for 83% of misusers/diverters. We can use education about misuse, pill counts, contracts on dosing, or switching to long-acting or nonstimulants to curb this.

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Additional concerns

 

With more ADHD diagnosis and stimulants used for many years should we worry about longer-term issues? There have been reports in rodent models and a few children of chromosomal changes with stimulant exposure, but reviewers do not interpret these as an individual cancer risk. Record review of patients who received stimulants showed lower numbers of cancer than expected. Nor is there evidence of reproductive effects of stimulants, although use during pregnancy is not cleared.

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Stimulants carry a boxed warning as having high potential for abuse and psychological or physical dependence, which is unsurprising given their effects on brain reward pathways. However, neither past nor present use of stimulants for ADHD has been associated with greater substance use long term.

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To top off these issues, recent shortages of stimulants complicate ADHD management. Most states require electronic prescribing, US rules only allowing one transfer of such e-prescriptions. With many pharmacies refusing to tell families about availability, we must make multiple calls to locate a source. Pharmacists could help us by looking up patient names of abusers on the registry and identifying sites with adequate supplies.

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While we need to educate ourselves and our patients about potential and manifest side effects and risks of stimulants, we need to balance those concerns with their high effectiveness for improving daily functioning of our many patients with ADHD.

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MDedge News. E-mail her at pdnews@mdedge.com.