When administering stimulants to adults, consider the individual’s total dosage requirement and daily schedule. Will he or she fare better with multiple daily dosing or a sustained-release form? How long is his or her average day? Does the patient have to be alert for 12 hours—or longer?
Some patients cannot sleep unless they take their last stimulant dose at bedtime. Others will have insomnia if a last dose is taken too late in the afternoon, especially with a sustained-release formulation.
When starting a patient on stimulants, begin with a 12-hour day and titrate the dosage—usually up, sometimes down—depending on response and side effects. Educating patients about their medications enables them to participate in decision-making.
Common side effects of stimulants include insomnia, decreased appetite, upset stomach, headache, anxiety, agitation, and increased pulse rate and blood pressure. The increase in blood pressure is usually less than 10%, but patients with poorly controlled hypertension should not be treated with stimulants until their blood pressure is well controlled. Until more is known about long-term effects, periodic assessment of blood pressure may be warranted.
Table 2
STIMULANT THERAPY FOR ADULTS WITH ADHD
| Stimulants | Starting dosage | Titration rate | Usual dosing interval | Maximum dosage in adults | |
|---|---|---|---|---|---|
| Methylphenidate | |||||
| Short-acting | |||||
| d, l-methylphenidate (Ritalin, Methylin) | 5 mg qd or 5 mg bid | 5 to 10 mg every 3 to 5 days | Every 3 to 4 hours Usually bid-tid | Average oral dosage 0.92 mg/kg/d; best response to 1.0 mg/kg/d16 | |
| Intermediate-acting | |||||
| d, l-methylphenidate (Ritalin SR, Metadate ER, Methylin ER) | 20 mg Ritalin SR; 10 mg Methylin ER or Metadate ER | 10 to 20 mg per week | qd to bid | ||
| d-methylphenidate (Focalin) | 2.5 mg bid | 2.5 to 5 mg per week | bid, at least 4 hours apart | ||
| Long-acting | |||||
| d, l-methylphenidate (Concerta) | 18 mg qd | 18 mg every 3 to 5 days | 12+ hours, usually qd | ||
| d, l-methylphenidate (Metadate CD) | 20 mg qd | 20 mg per week | qd | ||
| Amphetamine | |||||
| Short-acting | |||||
| (Dexedrine, Dextrostat) | 2.5 to 5 mg qd | 2.5 to 5 mg every 3 to 5 days | Every 4 to 6 hours Usually bid-tid | ||
| Intermediate-acting | |||||
| Mixed salts (Adderall) | 5 mg qd or 5 mg bid | 5 to 10 mg every 3 to 5 days | Every 4 to 6 hours Usually qd to bid | Average dosage 54 mg/d divided in two doses; maximum 30 mg bid | |
| (Dexedrine Spansule) | 5 or 10 mg qd | 5 mg per week | qd | ||
| Long-acting | |||||
| (Adderall XR) | 10 mg qd | 10 mg per week | qd | ||
| Stimulant | |||||
| Pemoline (Cylert) | 37.5 mg qd | 18.75 mg per week | qd; typical range 56.25 to 75 mg qd | Maximum dosage 112.5 mg/d | |
NONDRUG THERAPIES FOR ADULTS WITH ADHD
- Organized and orderly home and working environment
- Designated work/study space at home
- Designated coach to supervise work/study
- Healthy meals at regularly scheduled times
- Regular exercise
Adults with ADHD have been treated with mixed amphetamine salts with positive results. In a 7-week controlled, crossover study, 27 adults with ADHD received an average of 54 mg/d administered in two doses. Symptoms improved significantly—a 42% decrease on the ADHD Rating Scale. The medication was well-tolerated, and 70% of those receiving mixed amphetamine salts improved, compared with 7% of those who received a placebo.4
Duration of action of mixed salts of amphetamine has been measured at 3.5 hours with a 5-mg dose and 6.4 hours with a 20-mg dose.5 With methylphenidate, a dose of 12.5 mg worked for 4 hours. The maximum recommended dosage of mixed salts of amphetamine is 40 mg/d in divided doses.
Stimulant medications are well-tolerated. Addiction and the need for increased dosages can occur over long-term use (months to years). Reducing the dosage or switching from methylphenidate to an amphetamine variant can usually prevent these problems.
The FDA recently approved a single-enantiomer form of methylphenidate. It contains only the active “d” enantiomer, whereas the racemic mixture contains both the “d” and “l” enantiomers. Because the “l” enantiomer is inert, the resulting medication is more potent and may be prescribed at half the dosage of the racemic mixture.
Pemoline, a once-daily stimulant, is considered a second-line treatment because of reports of hepatic failure in some patients. Its use requires written informed consent and liver function tests at baseline and every 2 weeks. In a controlled trial, pemoline at high dosages (120 to 160 mg/d) was found moderately effective in adults with ADHD.6
Newer options: Longer-acting stimulants
Newer forms of slow-release methylphenidate and mixed amphetamine salts with sophisticated delivery systems are available.
Metadate CD is delivered in capsules containing beads with polymer coatings that dissolve and release their contents at different times. The capsules contain a 30:70 ratio of immediate- and extended-release beads.
Metadate CD has not been tested for adults in controlled clinical trials. In children ages 6 to 15, a single morning dose has been shown to be clinically effective in the morning and afternoon. A supplemental immediate-release capsule can be given in the morning if a patient’s medication levels need to be increased quickly. Dosage supplementation may also be required later in the day.