Because some ADHD children have partial or no response to different medicines, combinations are prescribed often. Combining dopamine and norepinephrine enhancers for ADHD has been done for over 30 years, as with methylphenidate (Ritalin) and imipramine (Tofranil). However, no prospective research on combination effectiveness and safety has been done with modern medicines. Preliminary and pilot results of two informative contributions using OROS methylphenidate (Concerta) and atomoxetine (Strattera) were presented as New Research Posters at the National Institute of Mental Health New Clinical Drug Evaluation Unit meeting in June 2006. Dr. Timothy Wilens first treated open label 33 children, average age 9, with atomoxetine dosed at 1.4 mg/kg for 4 weeks. Eleven of these children achieved full remission of their ADHD as rated by both ADHD RS core symptoms and the Clinical Global Impression Severity Scale (CGI-S). The children who only partially responded then received added OROS methylphenidate up to 54 mg/day. Partial atomoxetine response was defined as mild or moderate ADHD severity according to the CGI-S, a score of 3 or 4. The addition of methylphenidate reduced the partial responder group mean score from 3.4 to 2.9. The safety monitoring showed no serious consequences of the combined medicines. However, the common side effects of both medicines appeared increased in the combination treatment over atomoxetine alone, particularly in younger children. Discussing the poster, Drs. Rubin and Wilens agreed that pre-adolescents may react more variably to several forms of psychotropic medicine and need closer monitoring. As often occurs with one medicine treatment, the additive side effects may decrease with use longer than this study's one week. While these preliminary results support a better quantity of ADHD response in some children, more research is needed to confirm the different qualities of benefit clinically observed with methylphenidate and atomoxetine. .

The second NCDEU study was directed by Dr. Gabrielle Carlson and attempted a double blind, placebo controlled examination of first, atomoxetine response in ADHD children who did not respond to prior stimulant treatment despite good tolerability, and secondly, the safety and efficacy of augmenting atomoxetine with added OROS methylphenidate. Twenty five children, mean age 9.5, received 4 weeks of atomoxetine up to 1.4 mg/kg plus a placebo. The ADHD-RS core symptoms improved to full remission in 43% of the patients. This group was continued on atomoxetine and placebo. Half of the partial responders then received added methylphenidate up to 1.1 mg/kg, and half continued their atomoxetine and placebo. No additional improvement occurred as measured by the ADHD-RS and Clinical Global Impression Severity Scale. While the small sample size did not allow statistical significance calculation, the treatment conclusions showed that ADHD children who have not responded to stimulants may respond well to atomoxetine. However, prior stimulant failure predicts continued resistance to methylphenidate augmentation benefit. The frequency of treatment emergent adverse events did not increase, but greater weight loss was associated with the medicine combination.

Dr. Rubin practices Child and Adult Psychiatry, directs The Clinical Study Center in Burlington Vermont, and serves as Clinical Associate Professor at the University of Vermont College of Medicine. Click here for more information about Dr. Rubin and ADHD.

ADHD Headline News

• ADHD in Adults: New England Journal of Medicine
• Adults with ADHD often don't seek treatment
• Midbrain, striatal and amygdalar dopaminergic dysfunction in ADHD
• The Family Environment and Adolescent Well-Being
• ADHD and Medication: Practical updates for Canadian healthcare
  

Advertisement

Advertisement