If you play a game of word association and someone says “Attention-Deficit/Hyperactivity Disorder” or “ADHD”, your mind might jump to words like naughty, crazy or dreamer, or to phrases like “out of control” or “off the wall”. Another association might be with Ritalin®. What is Ritalin®? Ritalin® is the trade name of the drug methylphenidate. What is methylphenidate? Methylphenidate is a psychostimulant.
That sounds like a scary word, doesn’t it? When you start thinking about Ritalin®, there might be a few other words or phrases that spring to mind, like dangerous, addictive, harmful, mind-altering, poisonous, heart attacks or growth stunting. Before you get yourself completely stressed out about these words and phrases, let’s explore the reasons for use of this drug and others for the treatment of ADHD.
How is ADHD treated?
Due to the complex nature of ADHD, it cannot be adequately managed using a single treatment. Much like the procedure for its diagnosis, its management also requires a multidisciplinary approach to address as many facets of the condition as possible. Unfortunately, ADHD often occurs with other psychological conditions such as mood disorder (depression and bipolar disorder), anxiety and oppositional defiant disorder. When there are other comorbid conditions, management becomes even more complicated. Interventions which are primarily recommended include psycho-education, behavioural interventions, parent training and school support. Pharmacological treatment is indicated in conjunction with these interventions if they do not result in sufficient management of symptoms.
Psychostimulant treatment
Psychostimulants, such as the aforementioned methylphenidate, are the first line medicinal management for ADHD. As a class of drugs there is well established safety and efficacy, however other drugs are needed as between 10% and 30% of individuals do not respond to stimulant treatment or unable to tolerate the side effects due to it. Reasons for the stigma attached to use of these drugs include the fear that they promote drug addiction, the lack of long term benefits following removal of the drug, reports of decreases in physical growth and, although rare, the potential to induce tics, seizures and mania.
Methelphenidate (Ritalin® and Concerta®) is the most commonly used of all the ADHD-indicated stimulants and is the only one licensed for use in South Africa. Despite the safety concerns, efficacy of stimulants as class is reported to be between 70% and 96%. The mechanism of action of these drugs is not definitively known, but a number of theories exist based on the observed effects that methylphenidate exerts on neurotransmitters (chemical messengers) in the brain. The net result of methylphenidate on the brain is the increase in the amount of noradrenalin and dopamine available in the synapses of the frontal cortex and subcortical brain regions. This action in these specific areas helps to improve cognitive functions such as memory, decision making and attention.
This drug is available in both immediate and controlled release formulations. It has a relatively rapid onset of action, but it does not accumulate in the body, thus repeated daily administration is required for sustaining the drug effect. It is indicated for use in the treatment of ADHD in children (and adults) from the age of six years, but is often used in children younger than this under the care and monitoring of specialists. The dosages used are not necessarily dependent on the child’s age or weight, but are related more to the impairment experienced and the child’s ability to tolerate the drug and its effects. When initiating therapy it is advised that the lowest effective dose of 5mg twice a day is used and gradually increased over a number of weeks until therapeutic goals have been obtained.
Non-stimulant treatment
There is one other drug which is specifically indicated for the treatment of ADHD in South Africa. Atomoxetine is a non-stimulant drug and can be used for for ADHD in children (and adults) from the age of six years, it is a second line agent. Studies have evaluated its efficacy against that of methylphenidate with varied results, but some data indicate it is of comparable efficacy. A drawback to the use of atomoxetine is the delay between treatment initiation and onset of therapeutic effect as it can take between two and four weeks for changes to be observed.
Like methylphenidate, this drug also exerts changes in the levels of noradrenalin and dopamine in the brain by an unknown mechanism. A key difference between this agent and methylphenidate is that it does not affect the nucleus accumbens and striatum of the brain and as a result is less likely to be abused or induce tics.
Unlike methylphenidate, this drug is highly protein-bound, which means that it can remain in the body for a much longer period whereas methylphenidate is rapidly excreted. As a result, this drug cannot be abruptly discontinued and should be tapered off if therapy is no longer required or has to be stopped for whatever reason. Dosing is weight dependent and should be initiated at a low dose with gradual titration upwards.
Other pharmacological treatments
As previously mentioned, methylphenidate may either be ineffective or not well tolerated by all children (and adults). The same can be said for atomoxetine, thus there is a need for other drugs for the treatment of ADHD. Although these drugs are not directly indicated for ADHD and are used “off-label”, their use may be recommended in certain instances. These alternatives include imipramine (a tricyclic antidepressant), clonidine, bupropion (an antidepressant), modafinil (antidepressant) and some antipsychotic agents which may be uses in cases where severe aggression accompanies the ADHD. – Judith Regnart
Author Bio:
Judith is a wife, pharmacist, part-time PhD student, bellydancer and mother to three furry children. Although she hopes to start her own family in the near future, in the mean time she devotes her faculties to researching aspects of ADHD in the hope of positively contributing to understanding of the disorder. She has real life experience with her late-life ADHD diagnosed husband who is living proof that a difficult childhood of undiagnosed ADHD can be overcome and can be very rewarding creatively as evidenced by his photography business, www.nikregnart.com.
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