Examining Tolerance to CNS Stimulants in ADHD
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ClinicalTrials.gov Identifier: NCT02039908 |
Recruitment Status :
Completed
First Posted : January 20, 2014
Results First Posted : September 17, 2019
Last Update Posted : June 9, 2020
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Although stimulant medication is a well-established treatment for ADHD, it is often necessary for doctors to increase the dose over time to maintain the benefits of the medication. While medication can be very effective for improving symptoms of ADHD during the first year of use, it has not been found to significantly improve the long term course of children with ADHD. For example, in large research studies, groups of children who take medication for ten years do not have consistently better academic grades than groups of children who never used medication (individual results will vary from child to child).
In order to help children with ADHD achieve the best possible outcomes, it is important for doctors to study why this happens. One possible reason is development of tolerance to the medication. Tolerance means that a drug's effects decrease when it is taken consistently over time, so that an increased dose is needed to continue showing effects. Some doctors believe that children who take stimulant medication for ADHD develop tolerance to it which would explain why benefits may not persist over time, but no research studies have been done to measure whether this occurs. This study aims to see if children show a tolerance effect to stimulant medication and whether that tolerance can be prevented by taking short breaks from the medication called medication holidays.
Condition or disease | Intervention/treatment | Phase |
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Attention-deficit/Hyperactivity Disorder | Drug: Methylphenidate | Phase 4 |
This is an innovative evaluation of tolerance using an objective measure in an analog classroom. Each subject will complete the a 10-minute math test twice a day for three weeks on optimal dose or placebo, and then be crossed over to the other condition. Within-subject drug/placebo differences will be compared over the three weeks of exposure to assess tolerance in the analog setting.
When school commences, 50% of the sample will be randomized to 7-day-a-week (continuous) dosing and 50% to 5-day-a- week (weekend holidays) dosing to examine the efficacy of prescribed weekend drug holidays for combatting need for dose escalations (tolerance) during the school year.
Participants will be assessed monthly to detect deteriorating functioning. Using a standardized protocol, study physicians will increase dose for subjects in either arm who meet defined impairment thresholds. The difference between the two dosing conditions will inform regarding how best to deal with tolerance in clinical application.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 267 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | Examining Tolerance to CNS Stimulants in ADHD |
Study Start Date : | April 2013 |
Actual Primary Completion Date : | May 2018 |
Actual Study Completion Date : | March 2020 |

Arm | Intervention/treatment |
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Active Comparator: Methylphenidate 7-day dosing
During the school year, children in this arm will receive 7-day dosing of medication.
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Drug: Methylphenidate
Children will receive a double-blind assessment to determine their optimal starting dose of Concerta. Doses will be adjusted over the course of the school year and inceased if tolerance to the medication is detected.
Other Name: Concerta |
Active Comparator: Methylphenidate 5-day dosing
During the school year phase, these children will receive 5-day dosing with weekend holidays.
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Drug: Methylphenidate
Children will receive a double-blind assessment to determine their optimal starting dose of Concerta. Doses will be adjusted over the course of the school year and inceased if tolerance to the medication is detected.
Other Name: Concerta |
- Number of Dose Changes Required Per Protocol [ Time Frame: 10 months ]Monthly evaluations of medication efficacy will be used to determine whether dose adjustments are needed due to anticipated tolerance effects.
- Time to First Dose Increase [ Time Frame: 10 months ]The amount of time elapsed before a child requires a dose increase during the school year will be measured in months.
- Endpoint Medication Dose [ Time Frame: End of Phase 2 School Year ]Dose of medication reported in mg/kg/day

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Ages Eligible for Study: | 6 Years to 12 Years (Child) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Diagnosis of attention-deficit/hyperactivity disorder
- Full Scale IQ above 80
Exclusion Criteria:
- Psychotropic medications for conditions other than ADHD
- Active medical or psychiatric conditions that could be worsened by stimulants
- Diagnosis of Autism or Asperger's Disorder
- Documented intolerance fo methylphenidate or failed trial of OROS MPH

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02039908
United States, Florida | |
Florida International University Center for Children and Families | |
Miami, Florida, United States, 33199 |
Principal Investigator: | William E Pelham, Ph.D. | Florida International University | |
Principal Investigator: | James M Swanson, Ph.D. | Florida International University |
Documents provided by Florida International University:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Florida International University |
ClinicalTrials.gov Identifier: | NCT02039908 |
Other Study ID Numbers: |
MH099030 |
First Posted: | January 20, 2014 Key Record Dates |
Results First Posted: | September 17, 2019 |
Last Update Posted: | June 9, 2020 |
Last Verified: | May 2020 |
Tolerance to stimulant medication |
Attention Deficit Disorder with Hyperactivity Attention Deficit and Disruptive Behavior Disorders Neurodevelopmental Disorders Mental Disorders Methylphenidate Central Nervous System Stimulants Physiological Effects of Drugs |
Dopamine Uptake Inhibitors Neurotransmitter Uptake Inhibitors Membrane Transport Modulators Molecular Mechanisms of Pharmacological Action Dopamine Agents Neurotransmitter Agents |