Lisdexamfetamine (Vyvanse) Dosage Recommendations
The recommended starting dosage for lisdexamfetamine (Vyvanse) is 30 mg once daily in the morning, with dosage adjustments in increments of 10-20 mg at approximately weekly intervals up to a maximum recommended dosage of 70 mg once daily. 1
Initial Dosing and Titration
- Starting dose: 30 mg once daily in the morning
- Titration schedule: Increase by 10-20 mg at approximately weekly intervals
- Maximum dose: 70 mg once daily
- Administration time: Morning (to avoid insomnia)
Administration Methods
Lisdexamfetamine may be administered in one of the following ways:
- Swallow capsules whole
- Open capsules and mix entire contents with yogurt, water, or orange juice
- Take with or without food 1
Dosage Adjustments for Special Populations
Renal Impairment
- Severe renal impairment (GFR 15 to <30 mL/min/1.73 m²): Maximum 50 mg once daily
- End-stage renal disease (GFR <15 mL/min/1.73 m²): Maximum 30 mg once daily 1
Drug Interactions
- Agents that alter urinary pH can impact blood levels of amphetamine:
- Acidifying agents (e.g., ascorbic acid) decrease blood levels
- Alkalinizing agents (e.g., sodium bicarbonate) increase blood levels
- Adjust dosage accordingly 1
Monitoring and Follow-up
Regular monitoring is essential for patients on lisdexamfetamine:
- Assess symptom control using standardized rating scales 2
- Monitor for common side effects:
- Decreased appetite
- Insomnia
- Irritability
- Dizziness
- Weight loss 3
- Check vital signs annually in children and quarterly in adults 2
- Follow up within 2-4 weeks after dose adjustment 2
Clinical Considerations
Pre-treatment Screening
Before initiating treatment:
- Assess for cardiac disease (careful history, family history of sudden death or ventricular arrhythmia, physical exam)
- Evaluate risk of abuse
- Keep careful prescription records 1
Pharmacokinetics
Lisdexamfetamine is a prodrug that is converted to active d-amphetamine after oral ingestion:
- Median time to maximum plasma concentration: 1 hour for lisdexamfetamine, 3 hours for d-amphetamine
- Terminal elimination half-life: 0.47 hours for lisdexamfetamine, 10.39 hours for d-amphetamine 4
Common Pitfalls and Caveats
- Afternoon dosing: Avoid afternoon doses due to potential for insomnia 1
- Dividing doses: Do not take less than one capsule per day or divide a single dose 1
- Storage of mixed medication: When mixing with food or liquid, consume immediately and do not store 1
- Abuse potential: Although lisdexamfetamine has reduced abuse potential compared to immediate-release stimulants due to its prodrug nature, it still carries risk for abuse and dependence 3, 5
- Weight monitoring: Regular weight monitoring is essential as decreased appetite and weight loss are common side effects 2
By following these dosage recommendations and monitoring guidelines, clinicians can optimize the efficacy of lisdexamfetamine while minimizing potential adverse effects in patients with ADHD.