ADHD and epilepsy are both relatively common conditions so may
often occur together. Although it is commonly held that stimulants
lower the seizure threshold at the doses used to treat ADHD, they
in fact have minimal effect. Studies (Gross-Tsur et al 1997) have
found that in children with ADHD who are maintained on effective
anticonvulsant doses, stimulant treatment was effective against the
symptoms of ADHD and produced no increase in seizure frequency, EEG
or difficulty in regulating anticonvulsant levels. It would
therefore seem reasonable to treat children with well-controlled
epilepsy and ADHD with a combination of anticonvulsant and
methylphenidate.
However, due to the drug interactions between methylphenidate
and anticonvulsants (see
drug
interactions ), it is important to monitor anticonvulsant
plasma levels carefully to avoid toxicity. The situation with
children whose epilepsy is less controlled is less well understood
and dexamphetamine may be a more appropriate choice in this
group.