From the Guidelines
Adding a 10 mg PRN dose of lisdexamfetamine dimesylate (Vyvanse) to an existing 40 mg daily regimen for strenuous academic activities is not advisable. According to the most recent guidelines, the maximum daily dose of lisdexamfetamine dimesylate is not explicitly stated, but the general consensus is to avoid exceeding the recommended daily dose to minimize the risk of side effects 1. The medication is designed for once-daily use, with a long duration of action, making it unsuitable for as-needed dosing.
The primary concern with adding a PRN dose is the potential increase in side effects, such as increased heart rate, blood pressure elevation, insomnia, and anxiety. Additionally, intermittent dosing could lead to inconsistent medication levels, complicating the assessment of the regular treatment's effectiveness.
If the current 40 mg dose seems inadequate, a better approach would be to discuss with the prescribing physician about possibly adjusting the regular daily dose or exploring alternative treatment strategies, such as non-pharmacological approaches for managing ADHD symptoms during particularly demanding academic periods. The guidelines suggest that doses may be adjusted in weekly increments of 5 to 10 mg per dose, but it is essential to prioritize caution and avoid exceeding the recommended daily dose 1.
Key considerations for managing ADHD symptoms include:
- Using a consistent titration schedule
- Assessing drug response and side effects regularly
- Providing a schedule for initial titration and monitoring
- Considering alternative treatment strategies, such as non-pharmacological approaches, when necessary.
Ultimately, the decision to adjust the medication regimen should be made in consultation with the prescribing physician, taking into account the individual patient's needs and response to treatment 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION Indicated PopulationInitial DoseTitration ScheduleRecommended DoseMaximum Dose ADHD (Adults and pediatric patients 6 years and older) (2.2)30 mg every morning10 mg or 20 mg weekly30 mg to 70 mg per day70 mg per day
The FDA drug label does not provide guidance on adding 10 mg PRN of lisdexamfetamine dimesylate for a patient already taking 40 mg for ADHD. The maximum dose listed is 70 mg per day, but there is no information on PRN dosing or adjusting the dose for strenuous academic activity. Therefore, no conclusion can be drawn, and it is advisable to consult with a healthcare professional for personalized guidance. 2
From the Research
Lisdexamfetamine Dosing for ADHD
- The patient is currently taking 40 mg of lisdexamfetamine dimesylate for ADHD and requires an additional dose for strenuous academic activity.
- Adding 10 mg PRN of lisdexamfetamine dimesylate may be considered, but the evidence is limited.
Pharmacokinetics and Pharmacodynamics
- A study comparing the pharmacokinetics and pharmacodynamics of lisdexamfetamine and D-amphetamine found that lisdexamfetamine has a longer lag time and reaches peak levels later than D-amphetamine 3.
- However, the study also found that lisdexamfetamine and D-amphetamine have similar maximal concentrations and total exposure.
Efficacy and Safety
- Lisdexamfetamine dimesylate has been shown to be effective in the treatment of ADHD in children and adults, with significant improvements in symptoms and functioning 4.
- The most common adverse events reported with lisdexamfetamine dimesylate include decreased appetite, insomnia, upper abdominal pain, headache, irritability, weight loss, and nausea 4.
Dosing Strategy
- A meta-analysis of stimulant dose and dosing strategy in the treatment of ADHD found that flexible titration of stimulants as needed can be associated with improved efficacy and acceptability 5.
- However, the study also noted that fixed-dose trials may underestimate the true potential benefit of trialing dose-increases of stimulants in clinical practice.
Abuse Potential
- A review of the potential for abuse of lisdexamfetamine in adults found that the prodrug property of lisdexamfetamine reduces the risk of misuse, and that epidemiological studies have found lower abuse rates of lisdexamfetamine compared to immediate-release dexamphetamine 6.
- However, the review also noted that more long-term pharmaco-epidemiological studies are needed to confirm these findings.
Clinical Efficacy and Safety in Binge Eating Disorder
- Lisdexamfetamine has been shown to be effective in the treatment of moderate to severe binge eating disorder, with significant reductions in binge eating days per week 7.
- Commonly reported side effects of lisdexamfetamine in the treatment of binge eating disorder include dry mouth, insomnia, weight loss, and headache.