High Dose Methylphenidate Treatment in Adult Attention Deficit Hyperactivity Disorder

A Case Report

Michael Liebrenz; Danielle Hof; Anna Buadze; Rudolf Stohler; Dominique Eich

Disclosures

J Med Case Reports. 2012;6(125) 

In This Article

Abstract and Introduction

Abstract

Introduction Stimulant medication improves hyperactivity, inattention, and impulsivity in both pediatric and adult populations with Attention Deficit Hyperactivity Disorder (ADHD). However, data regarding the optimal dosage in adults is still limited.
Case presentation We report the case of a 38-year-old Caucasian patient who was diagnosed with Attention Deficit Hyperactivity Disorder when he was nine years old. He then received up to 10 mg methylphenidate (Ritalin®) and 20 mg sustained-release methylphenidate (Ritalin SR®) daily. When he was 13, his medication was changed to desipramine (Norpramin®), and both Ritalin® and Ritalin SR® were discontinued; and at age 18, when he developed obsessive-compulsive symptoms, his medication was changed to clomipramine (Anafranil®) 75 mg daily. Still suffering from inattention and hyperactivity, the patient began college when he was 19, but did not receive stimulant medication until three years later, when Ritalin® 60 mg daily was re-established. During the 14 months that followed, he began to use Ritalin® excessively, both orally and rectally, in dosages from 4800–6000 mg daily. Four years ago, he was referred to our outpatient service, where his Attention Deficit Hyperactivity Disorder was re-evaluated. At that point, the patient's daily Ritalin® dosage was reduced to 200 mg daily orally, but he still experienced pronounced symptoms of, Attention Deficit Hyperactivity Disorder so this dosage was raised again. The patient's plasma levels consistently remained between 60–187 nmol/l—within the recommended range—and signs of his obsessive-compulsive symptoms diminished with fluoxetine 40 mg daily. Finally, on a dosage of 378 mg extended-release methylphenidate (Concerta®), his symptoms of Attention Deficit Hyperactivity Disorder have improved dramatically and no further use of methylphenidate has been recorded during the 24 months preceding this report.
Conclusions Symptoms of Attention Deficit Hyperactivity Disorder (ADHD) in this adult patient, who also manifested a co-occurring obsessive compulsive disorder, dramatically improved only after application of a higher-than-normal dose of methylphenidate. We therefore suggest that clinicians consider these findings in relation to their adherence to current therapeutic guidelines.

Introduction

Attention Deficit Hyperactivity Disorder (ADHD) is a prevalent mental disorder characterized by symptoms of inattention (distractibility), hyperactivity, and impulsivity—all of which contribute to significant psychosocial impairment in the affected individuals.[1] Previously believed to be solely a disorder of childhood and adolescence, it is now accepted that about two-thirds of children diagnosed with ADHD will experience its symptoms in adulthood.[2,3] For example, adults suffering from ADHD are less frequently employed on a fulltime basis, have difficulty maintaining personal relationships, and are generally less satisfied with their families and their social and professional lives.[4]

Prevalence of adult ADHD in the United States is estimated at around 4.4%, and the disorder is highly co-morbid with many other DSM IV disorders.[1,5,6] Although clinicians widely agree that a treatment approach which combines psychotherapeutic and pharmacological interventions is optimal, the prescription of stimulant medication is clearly the first line of treatment and is known to improve symptoms in both pediatric and adult populations.[7] In particular, the use of methylphenidate (MPH), has proved an efficacious pharmacological treatment for adult ADHD when administered in weight-adjusted doses equivalent to those used in a pediatric population.[8]

Although the mechanism that underlies the action of stimulants in adult ADHD is still being investigated, the efficacy of both amphetamines and MPH is attributed to their ability to increase striatal and cortical dopamine levels.[9] While both drugs share common mechanisms of action, amphetamines increase dopamine release, whereas MPH inhibits re-uptake of dopamine by blocking the dopamine transporter (DAT).[9,10]

Oral formulations of MPH are available in short- and intermediate-acting preparations, as well as slow-release and long-acting ones. Oral administration of immediate-release MPH reaches peak plasma concentration after two hours, and decreases thereafter.[5]

As a consequence, immediate-release MPH must be taken several times a day—and, even so, spikes in plasma level occur. On the other hand, long-acting formulations, such as once-daily osmotic release oral system (OROS) MPH (Concerta®), improve patient compliance and demonstrate efficacy similar to that of an immediate-release dose of MPH three times daily.[11] Data on the optimal dosage of these stimulants in adults is still limited, with upper-limit recommendations usually being 1 mg/kg for methylphenidate and 0.5 mg/kg for dexamphetamine.[8]

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