Can Vyvase (hydroxyurea) be taken twice a day?

Vyvanse (Lisdexamfetamine) Dosing: Once Daily Administration Only

Vyvanse (lisdexamfetamine) should NOT be taken twice daily, as it is specifically designed and FDA-approved for once-daily dosing only.

Mechanism and Duration of Action

Vyvanse is a prodrug stimulant medication that works differently from immediate-release stimulants:

• Lisdexamfetamine is inactive until metabolized in the body to dextroamphetamine
• This metabolism provides a gradual, sustained release mechanism
• The active metabolite provides clinical effects lasting 10-14 hours for most patients
• Taking a second daily dose would disrupt the intended pharmacokinetic profile and increase risk of side effects

Evidence-Based Rationale for Once-Daily Dosing

The FDA-approved labeling for Vyvanse clearly establishes it as a once-daily medication. This is based on:

1. The prodrug formulation specifically designed for once-daily administration
2. The long duration of action (10-14 hours) that covers a full day's needs
3. The potential for increased adverse effects with multiple daily doses, including:
   • Insomnia
   • Cardiovascular effects (increased heart rate, blood pressure)
   • Appetite suppression
   • Anxiety/agitation

Common Dosing Mistakes and Concerns

Taking Vyvanse twice daily could lead to several problems:

• Disrupted sleep patterns due to stimulant effects lasting into nighttime
• Increased risk of cardiovascular side effects
• Potential for medication tolerance developing more quickly
• Risk of exceeding maximum recommended daily dosage

Appropriate Dosing Adjustments

If the current dose of Vyvanse is not providing adequate symptom control throughout the day:

1. Discuss with the prescriber about increasing the single daily dose (available in 10,20,30,40,50,60, and 70 mg strengths)
2. Take the medication earlier in the day to better align with when symptom control is needed
3. Consider if an adjunctive short-acting stimulant might be appropriate for "breakthrough" symptoms (under medical supervision)
4. Evaluate if a different medication might be more appropriate for the patient's needs

Patient Education Points

• Take Vyvanse in the morning with or without food
• Maintain consistent timing of the dose each day
• Do not split, crush, or attempt to divide doses
• If a dose is missed, take it as soon as remembered, but not if it's late in the day
• Never take more than the prescribed daily dose

Conclusion

Vyvanse is specifically designed as a once-daily medication with a duration of action that covers the full day for most patients. If symptom control is inadequate, the solution is not to take multiple doses but to work with the prescriber on appropriate dose adjustments or medication changes.