Twenty-four participants with uncontrolled epilepsy and ADHD in this prospective study, conducted at University of Joinville, Santa Catarina, Brazil, were 7 -16 years of age. They had been followed for at least 6 months before introduction of methylphenidate (MPH), and had at least 2 seizures treated with antiepileptic drugs. MPH dose started at 5 mg once or twice daily, and was increased by 10 mg weekly as necessary, not exceeding 60 mg daily. MPH was effective in control of ADHD in 70.8% patients, no change in 20.8%, and symptoms were worse in 8.3%. Compared to the previous 6 months, seizures were increased in number in 2 children (8.3%)(P<0.001), and not increased in 22 (91.6%); 7 patients had fewer seizures; 58.3% had partial epilepsy and 41.7% generalized epilepsy. ADHD was inattentive type in 41.7%, combined type in 37.5%, and 20.8% hyperactive/impulsive type. Results of 11 previous reports of MPH, ADHD and epilepsy are summarized: 5 studies reported an increase in seizures and 6 showed no increase. One controlled study of OROS-MPH observed a daily increased risk of seizures with increasing doses of the stimulant. [1]
COMMENT. The majority of studies reporting no or small risk of seizures with MPH and epilepsy involve patients whose seizures are controlled with AEDs. Few studies investigate the safety of MPH and other stimulants in treatment of ADHD in children with epilepsy or epileptiform EEG, not treated with AEDs.
In a group of 234 children with uncomplicated ADHD who received EEGs, 36 (15.4%) showed epileptiform abnormalities, 40% rolandic spikes and 60% focal abnormalities. With introduction of stimulant therapy in 205 (87.6%) patients, seizures occurred only in the stimulant-treated group: in one of 175 (0.6%) patients with a normal EEG and in 3 (10%) of 30 with epileptiform EEGs. Seizures occurred in 2 of 12 (16.7%) with EEG rolandic spikes [2]. The authors suggest that an epileptiform EEG in neurologically normal children with ADHD predicts considerable risk for the occurrence of seizures during stimulant therapy whereas a normal EEG carries minimal and no increased risk.