A double-blind, crossover, 6 week study at the Departments of Psychology and Psychiatry, State University of New York at Buffalo, compared the efficacy and time-course of Ritalin^® (10 mg and 17.5 mg bid), Adderal^® (7.5 mg and 12.5 mg), and placebo in 25 ADHD children, mean age 9.6 years. A beneficial response in behavior and academic productivity was obtained with both drugs in 75% of participants. The effects of the two drugs were similar, except that Adderal may be more potent and effects may persist for an hour or two longer than Ritalin. The midday doses of both drugs appear to be more effective than the morning doses, suggesting an additive effect, and an indication for using a relatively lower dose at lunch-time. Side effects were not significantly different for Ritalin and Adderal, although the reported incidence of tics, dysphoria, sleep disturbance, and loss of appetite was greater for Adderal. [1]

COMMENT. Adderal may offer a useful addition to the psychostimulant armamentarium for treatment of ADHD. It may be substituted for methylphenidate (MPH) when a longer acting drug is required, if MPH rebound symptoms are troublesome, and when children object to receiving midday doses at school. Its superiority to Dexedrine has not been established, and both amphetamines have the disadvantage of mandatory triplicate prescriptions.

Methylphenidate versus dextroamphetamine in ADHD. Efron D, commenting on the Adderal study by Swanson et al (1998), refers to his experience and comparative trials of MPH and dextroamphetamine in 125 children with ADHD, at the Royal Children’s Hospital, Melbourne, Australia [2]. With dosages standardized at 0.15 mg/kg/bid for dextroamphetamine and 0.3 mg/kg/bid for MPH, beneficial effects were similar, though consistently favoring MPH. The incidence and severity of side effects were significantly greater with dextroamphetamine, particularly insomnia, irritability, crying, anxiousness, dysphoria, and nightmares. Dextroamphetamine is the preferred first-line stimulant for ADHD in Australia because of cost constraints. However, this study demonstrates the superiority of methylphenidate over an amphetamine, and in the US, MPH should be the drug of choice. Dextroamphetamine and Adderal are alternative therapies of proven value.

Short- and long-term safety and efficacy of stimulants in ADHD is reviewed by Greenhill LL et al. [3]. Long-term use of stimulants is not considered harmful.