Extended-Release Stimulant Recommendation for Teen with Appetite Suppression
Switch to an extended-release amphetamine formulation, specifically lisdexamfetamine (Vyvanse), which provides 13-14 hours of coverage with once-daily dosing and may have a different side effect profile regarding appetite suppression compared to methylphenidate. 1
Rationale for Switching Stimulant Classes
Stimulants remain first-line therapy even when side effects occur with one class, as the overall response rate when both methylphenidate and amphetamine are tried approaches 80-90%, and individual patients may respond to either class with markedly different side effect profiles 2
Guidelines recommend switching to the other stimulant class before considering non-stimulants, as both methylphenidate and amphetamine demonstrate equivalent efficacy for ADHD core symptoms with large effect sizes (approximately 1.0), significantly superior to non-stimulants 1, 2
Extended-release formulations improve adherence and eliminate the stigma and compliance problems associated with twice-daily dosing, particularly important for adolescents who may forget or feel embarrassed about in-school medication administration 1, 3
Specific Medication Recommendation
Start lisdexamfetamine 30 mg once daily in the morning, as this provides:
- 13-14 hours of continuous symptom coverage, eliminating the need for BID dosing 3
- Once-daily administration that improves adherence and reduces stigma 3
- A prodrug formulation with lower abuse potential compared to immediate-release stimulants, particularly relevant for adolescents 3
Titration strategy: Increase by 10-20 mg weekly based on response, up to a maximum of 70 mg daily 3
Managing Appetite Suppression During Transition
While switching stimulant classes:
- Administer the medication with breakfast and provide high-calorie drinks or substantial snacks late in the evening when stimulant effects have worn off 2
- Monitor growth parameters (height and weight) at each visit, as stimulants cause small decrements in growth velocity (approximately 1-2 cm reduction over 2-3 years), though this effect diminishes by the third year and final adult height appears unaffected 2
- Extended-release formulations may produce less pronounced peak effects and potentially milder appetite suppression compared to immediate-release or BID dosing 2
Why Not Non-Stimulants
Non-stimulants should be reserved as second-line therapy only after adequate trials of both methylphenidate and amphetamines because:
- Atomoxetine has a significantly smaller effect size (approximately 0.7) compared to stimulants (1.0) and requires 6-12 weeks to observe effects, making it considerably less effective 1, 4
- Atomoxetine also causes decreased appetite and initial gastrointestinal symptoms, potentially not solving the appetite problem 1, 4
- Alpha-2 agonists (guanfacine, clonidine) have similar smaller effect sizes (0.7) and cause somnolence/sedation in 15-20% of patients, which would be problematic for a teenager 1, 2
Monitoring Requirements During Transition
- Cardiovascular monitoring: Measure blood pressure and heart rate at baseline and regularly, as stimulants cause small increases (1-4 mmHg BP, 1-2 bpm HR on average) 2
- Growth tracking: Plot height and weight on growth charts at each visit to detect velocity changes early 2
- Psychiatric screening: Assess for mood changes, irritability, anxiety, or psychotic symptoms, which occur uncommonly but require immediate attention 2
- Substance abuse screening: Screen adolescents before prescribing any stimulant, as diversion and misuse are particular concerns in this age group 2
Common Pitfalls to Avoid
- Do not assume all stimulants will cause identical appetite suppression - individual response to methylphenidate versus amphetamine side effects varies significantly, and switching classes often resolves tolerability issues 2
- Do not prematurely switch to non-stimulants without trying the alternative stimulant class first, as this sacrifices significant efficacy (effect size 1.0 vs 0.7) 1
- Do not use older sustained-release methylphenidate formulations if considering staying with methylphenidate, as they provide only 4-6 hours of coverage and have delayed onset with lower peaks 3