Dosing of Adderall IR as an Adjunct to Vyvanse
When adding Adderall IR to a patient already taking Vyvanse, start with a low dose of 2.5-5 mg of Adderall IR in the afternoon when Vyvanse begins to wear off, and administer no later than 2:00 PM to avoid sleep interference. 1
Rationale for Adding Adderall IR to Vyvanse
Vyvanse (lisdexamfetamine) is a long-acting prodrug stimulant that can experience diminished effects in the afternoon, which can impact productivity, focus, and quality of life. Adding a small dose of immediate-release stimulant in the afternoon when Vyvanse begins to wear off can effectively extend coverage throughout the day 1.
Dosing Recommendations
- Initial dosing: Start with 2.5-5 mg of Adderall IR
- Timing: Administer when Vyvanse begins to wear off, typically in the early afternoon
- Administration time limit: Give no later than 2:00 PM to avoid interfering with sleep
- Maximum daily dose: Up to 50 mg daily of amphetamine total (including both Vyvanse and Adderall IR) 1
Pharmacokinetic Considerations
Lisdexamfetamine (Vyvanse) is a prodrug that is converted to D-amphetamine in the body. While it has a longer duration than immediate-release amphetamine formulations, its effects typically begin to diminish in the afternoon for many patients 2. Adderall IR contains a mixture of amphetamine and dextroamphetamine salts that has a more rapid onset of action compared to Vyvanse, making it suitable for afternoon supplementation 3.
Monitoring Parameters
When adding Adderall IR to a Vyvanse regimen, carefully monitor:
- Sleep disturbances: Adding afternoon medication may exacerbate insomnia
- Appetite suppression: Extended coverage may further reduce appetite throughout the day
- Rebound irritability: Watch for irritability as medication effects diminish
- Cardiovascular parameters: Monitor blood pressure and heart rate regularly
- Weight changes: Track weight due to potential appetite suppression 1
Management of Side Effects
- Insomnia: Ensure Adderall IR is given no later than 2:00 PM
- Appetite suppression: Encourage high-calorie snacks or drinks when medication effects wear off in the evening
- Rebound irritability: Consider overlapping dosing patterns to provide smoother transitions between doses 1
Follow-Up Recommendations
- Schedule follow-up visits every 3-4 weeks during the initial treatment phase
- Once stable, follow-up every 3-6 months
- Use standardized rating scales to monitor symptoms
- Assess side effects such as gastrointestinal issues, loss of appetite, changes in mood, and sleep disturbances 1
Cautions and Contraindications
- Combining Adderall IR and Vyvanse may increase the risk of adverse effects, including:
- Cardiovascular effects
- Appetite suppression and weight loss
- Sleep disturbances
- Anxiety and irritability
- Additive sympathomimetic effects 1
Clinical Pearls
- The lower dose of Adderall (5-10 mg) produces effects comparable to higher doses of methylphenidate 3
- Adderall IR has been shown to have behavioral effects that may persist longer than those of methylphenidate after individual doses 4
- For patients who need extended coverage throughout the day, consider Adderall XR as an alternative to the combination therapy, as it has shown efficacy for up to 12 hours in some studies 5
Remember that the goal of adding Adderall IR to Vyvanse is to optimize symptom control throughout the day while minimizing side effects and improving quality of life.