In the realm of ADHD medications, stimulants such as methylphenidate and amphetamine are widely used. A third stimulant, pemoline, was discontinued in the U.S. due to potential liver toxicity, although it remains available in other countries.
Response Rates and Medication Adherence
Approximately 75% of people respond positively to one stimulant and its delivery system. When both stimulants are tried sequentially, the response rate can increase to over 90%. It’s important to try different medications and delivery systems because each works differently in terms of digestion, absorption, and pharmacological profile. Unfortunately, the average duration for which people remain on ADHD medication is only about six months to three years, which presents a challenge in maintaining treatment adherence.
Advances in Delivery Systems
Over the past two decades, pharmaceutical companies have developed innovative delivery systems to sustain medication levels in the body for longer periods. Originally, ADHD medications lasted only three to four hours, necessitating multiple doses throughout the day, which was inconvenient and problematic, especially for children in school.
Now, various delivery systems have been engineered to maintain consistent blood levels of the medication:
- Pills: Immediate-release medications that last a few hours.
- Pump (Concerta): Utilizes osmotic-release oral system (OROS) technology for a steady release over 8-12 hours.
- Pellets (Adderall XR, Focalin XR): Time-release pellets dissolve at different times to maintain consistent medication levels.
- Patch (Daytrana): A transdermal system that provides continuous medication absorption through the skin.
- Pro-drug (Vyvanse): Lisdexamfetamine, which activates in the gut, providing a continuous release over 12-14 hours.
- Liquid and Gummy Forms: Various forms including immediate and sustained-release liquids, as well as chewable options.
- Delayed Release (Jornay PM): Taken at night, it activates in the morning, improving early morning functioning without the lag time seen with other medications.
Concerta’s Osmotic Pump
Concerta’s OROS system involves a capsule with a laser-drilled hole, containing two chambers of methylphenidate: an immediate-release outer layer and an inner paste. As water enters the capsule, it pushes the paste out through the hole, providing a consistent release of medication throughout the day.
Adderall XR’s Pellet System
Adderall XR uses a capsule filled with pellets, each coated to dissolve at different times, ensuring a steady release of medication. The capsule can be opened and sprinkled on food if the child has difficulty swallowing it.
Vyvanse’s Pro-Drug Mechanism
Vyvanse is a pro-drug, meaning it is inactive until metabolized in the gut, where an enzyme cleaves off a lysine molecule, activating the amphetamine. This system reduces the potential for abuse and provides a smooth, long-lasting effect.
Preschoolers and ADHD Medications
Research, including the Preschool ADHD Treatment Study (PATS), has shown that stimulants like methylphenidate are effective and safe for preschool children, though the effect size is smaller and the tolerance for side effects is lower compared to older children. Despite being effective, about 8% of preschoolers cannot tolerate the medication due to side effects.
Documented Effects of Stimulants
Stimulants improve a wide range of ADHD symptoms and related impairments, including:
- Attention and concentration
- Social relationships
- Academic performance
- Reducing risk of accidental injuries and improving driving skills
- Emotional regulation
Side Effects
The most common side effects include:
- Insomnia (50%)
- Loss of appetite (50%)
- Headache (20-40%)
- Stomach ache (20-40%)
Other less common side effects include emotional changes, irritability, tics, and temporary growth delays. It’s important to manage these side effects through medication adjustments.
Addressing Misconceptions
Common misconceptions about ADHD medications include:
- Addiction risk: There is no evidence that prescribed stimulants lead to addiction when taken orally and as prescribed.
- Overuse: The rate of stimulant use is well below the prevalence of ADHD, indicating under-treatment rather than overuse, especially among teens and adults.
- Performance enhancement: Although there is some misuse in college settings, it’s not as widespread as media suggests.
Conclusion
Stimulants like methylphenidate and amphetamine are safe and effective for treating ADHD, though they are not suitable for everyone. The development of various delivery systems has greatly improved the management of ADHD symptoms, providing more options to tailor treatment to individual needs. Understanding the benefits, side effects, and proper use of these medications can help maximize their effectiveness and improve the quality of life for those with ADHD.
Disclaimer: Always consult your doctor for personalized medical guidance.
References
- American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.).
- National Institute of Mental Health. (2017). Attention Deficit Hyperactivity Disorder. Available at: https://www.nimh.nih.gov
- Barkley, R. A. (2015). Attention-Deficit Hyperactivity Disorder: A Handbook for Diagnosis and Treatment. The Guilford Press.
- Hallowell, E. M., & Ratey, J. J. (2011). Driven to Distraction: Recognizing and Coping with Attention Deficit Disorder. Anchor Books.