Long-acting stimulants in ADHD
Long-acting stimulants in ADHD
Concerta, Ritalin LA, and Vyvanse are all medications used to treat ADHD, but they utilise different delivery systems and mechanisms within the body. These medications provide the benefit of single daily dosing, which is a significant consideration for children at school, as they can feel embarrassed about taking additional short-acting stimulants. Long-acting stimulants may also improve medication compliance.
Concerta
Delivery System: Concerta uses an advanced osmotic-controlled release oral delivery system (OROS), which operates like a “micro pump” within the body.
The tablet features a rugged, non-digestible shell with a laser-drilled hole at one end. After swallowing, a small amount of non-polymerised Methylphenidate in the outer coating dissolves rapidly, providing an initial quick effect within 10–15 minutes. Water from the gastrointestinal tract enters the tablet through a semi-permeable membrane, gradually swelling a special “push compartment” made of an osmotically active polymer. As the polymer swells, it pushes the Methylphenidate out through the tiny exit port at a controlled rate, ensuring a steady release of medication over 10–12 hours.
The internal structure is divided into two drug compartments: approximately 30% of the drug is in the first compartment (released earlier in the day), while 70% is in the second compartment (released later). This creates an “ascending dose” profile that helps maintain symptom control throughout the day.
Ritalin LA: Immediate and Delayed Release Beads
Ritalin LA utilises SODAS (Spheroidal Oral Drug Absorption System) technology, which comprises a blend of two types of beads in each capsule. It works by enhancing the levels of dopamine and norepinephrine in the brain.
Fifty per cent of the beads are immediate release, providing a rapid onset similar to standard Ritalin tablets. The remaining 50% are enteric-coated, delayed-release beads that dissolve more slowly, releasing the second half of the dose approximately four hours after the first dose. This design creates two peaks of medication in the bloodstream: one after taking the capsule and another several hours later, offering coverage for up to 8 hours.
If the capsule cannot be swallowed, it can be sprinkled onto apple puree or yoghurt with a teaspoon. It should not be chewed, as it may damage the outer coating, which is essential for delayed release. It shouldn’t be mixed with water and swallowed, as it does not dissolve, and the beads can adhere to the sides of the glass, rendering it inefficient for delivering contents. A high-fat diet can impact absorption, and fat can also harm the coating of the long-acting beads.
The side effects are similar to those linked with short-acting Methylphenidate. Occasionally, the medication may trigger psychotic symptoms such as hallucinations (seeing or hearing things that are not there), delusions (false beliefs), and manic symptoms (extreme energy, overexcitability, racing thoughts, and impulsivity) as side effects. This can occur even in individuals with no previous psychotic history.
The treatment in these cases involves ceasing the medication and, in some instances, considering antipsychotic medications. Psychotic symptoms are more commonly reported with amphetamines, but they can also occur with methylphenidate. Events that arise within one week of commencing the medication are typically transient and resolve without the need for antipsychotic medication. Regardless, seeking advice from a psychiatrist is crucial for future planning in these cases.
Lisdexamphetamine (Vyvanse)
Lisdexamphetamine is an inactive prodrug until it is metabolised in the body. Lisdexamphetamine is amphetamine combined with the amino acid lysine.
After ingestion, Lis dexamphetamine is absorbed into the bloodstream and subsequently converted by enzymes in the body (mainly in the blood) into its active form, dexamphetamine. This conversion process leads to a gradual onset and a long duration of action, typically lasting 10 to 14 hours. Because activation depends on metabolism, Lis dexamphetamine has a lower risk of abuse.
Lis dexamphetamine must be swallowed whole. The capsule may be opened, and the contents can be dissolved in water or yoghurt. Stir the mixture until it is fully dissolved, then drink it immediately. Depending on the dosage advised by the treating doctor, the dose can be adjusted as needed. It can be taken with or without food in the morning and typically begins to work within one to two hours. The effect will build up over the next few weeks.
The common side effects noted include poor appetite, insomnia, headaches, abdominal symptoms, dry mouth, dizziness, tachycardia, nervousness, and mood changes. It is not recommended to stop the medication abruptly; if the child needs to come off it, the dosage should be reduced over several weeks.
In combination with Lysine, Dexamphetamine is rendered inactive. Once inside the body, it is released slowly. Therefore, it does not provide an immediate “high” if injected, sniffed, or swallowed. Thus, it has little potential for abuse or addiction.
In clinical practice, the response to different agents is variable, as some patients’ reactions are unpredictable. Therefore, medication is individualised for patients, and dosages are adjusted by clinicians based on various factors. Regular reviews with clinicians experienced in these medications are essential for dose adjustments and monitoring side effects.
Case scenario – A 12-year-old child was diagnosed with ADHD and started on short-acting Ritalin. Once a steady state was achieved, he was switched to a long-acting form of Ritalin. On the same day, he experienced hallucinations, such as seeing God and talking about God, which was quite unusual for him. He was otherwise well. The medication was stopped temporarily, and a referral was made to the psychiatrist to seek advice on the psychotic symptoms.
Acknowledgement: I thank Dr Aster Kuriakose, a General Paediatrician and Specialist in Developmental Paediatrics, for reviewing the article and providing immensely valuable contributions.
Disclaimer
Brand names are used in this article as clinicians and patients may be more familiar with them; however, I have no affiliation with pharmaceutical companies. The article is intended for informational purposes and is not peer-reviewed. It aims to provide insights and share clinical experiences. The decision to initiate medication is made carefully by the relevant clinicians, considering various factors. Parents are advised to follow the guidance of the clinicians when treating ADHD with these medications.
Suggested resources
Mark Selikowitz. Fast Facts. ADHD. Oxford University Press, 2021
Christopher Green, Kit Chee. Understanding ADHD. Doubleday,2001