A research team has now established that a delayed-release stimulant, used for treatment of attention-deficit hyperactivity disorder (ADHD) may be associated with less abuse, when compared to other stimulant drugs. Therapeutic doses of Concerta (methylphenidate) in the form of an oral formulation have not been reported to produce subjective effects that may lead to drug abuse. The results of the study can be found in the American Journal Of Psychiatry.
It has been known from previous studies and pharmacological research that drugs that cause euphoria may lead to abuse. This however requires rapid delivery of the drug formulation to the brain. The researchers of the present study examined the delivery of two different formulations of methylphenidate and compared the abuse potential of the formulations.
Drugs such as methylphenidate, commonly given for treatment of ADHD act by inhibition of dopamine transporter. This molecule accounts for increased levels of the neurotransmitter in the brain. ADHD patients lose control over movement, behaviour and attention, as their brains do not regulate the dopamine levels effectively. Such stimulant drugs though provide control of ADHD symptoms, do have the potential of being abused.
A quick release, traditional drug formulation was compared to slow release formulation (Concerta) that is released over a 12 hour period, to precipitate a gradual increase in blood levels. 12 healthy individuals (no diagnosis of ADHD) were recruited for the present study and received either of the medications on a random basis. The study participants received drug dosages high enough to produce similar peak levels in both brain and the blood.
Positron emission tomography (PET scans) was taken before and after the test. In addition, the study participants were required to take up blood tests and fill up questionnaires regarding awareness of drug effects and whether they enjoyed or disliked those effects. Following analysis, it was found that those who received the quick release form of the drug enjoyed the drug effect compare to those who received the slow release formulation.
Although both the drug formulations were found to be effective in treating ADHD symptoms, the researchers documented diversity in levels of dislike and enjoyment of the drug effects. This effect could be seen even when similar high doses of the drugs were used. The researchers further highlight the need for more such studies to effectively analyze the safety and efficacy of ADHD drugs.