Switching from Guanfacine to Vyvanse for ADHD
Cross-taper guanfacine while initiating Vyvanse at standard starting dose, reducing guanfacine by 1 mg every 3-7 days to avoid rebound hypertension, while simultaneously titrating Vyvanse to therapeutic effect.
Discontinuation Protocol for Guanfacine
Never abruptly stop guanfacine—it must be tapered to avoid rebound hypertension. 1
- Taper guanfacine by 1 mg every 3-7 days until completely discontinued 1, 2
- Monitor blood pressure and heart rate during the taper, particularly at each dose reduction 1, 2
- Warn patients about potential withdrawal symptoms including rebound hypertension, which can occur with abrupt cessation 1
Initiation of Vyvanse (Lisdexamfetamine)
- Start Vyvanse at standard initial dosing (typically 30 mg once daily in the morning) on day 1 of the guanfacine taper 3
- Lisdexamfetamine works immediately, unlike guanfacine which requires 2-4 weeks for therapeutic effect, so patients will experience rapid symptom improvement 1, 3
- Titrate Vyvanse weekly based on response and tolerability while continuing the guanfacine taper 3
Cross-Tapering Timeline Example
Week 1:
- Start Vyvanse 30 mg each morning 3
- Reduce guanfacine from current dose by 1 mg 1
- Monitor blood pressure and heart rate 1
Week 2:
- Continue Vyvanse (adjust dose if needed based on response) 3
- Reduce guanfacine by another 1 mg 1
- Monitor cardiovascular parameters 1
Continue this pattern until guanfacine is fully discontinued 1
Critical Monitoring Parameters
- Measure baseline blood pressure and heart rate before initiating the switch 1, 2
- Monitor cardiovascular parameters at each guanfacine dose reduction 1, 2
- Watch for rebound hypertension during guanfacine taper 1, 2
- Assess ADHD symptom control systematically using parent and teacher reports during the transition 1
Important Clinical Considerations
- The pharmacological profiles of these medications are fundamentally different: guanfacine works through alpha-2A adrenergic mechanisms while lisdexamfetamine enhances dopaminergic and noradrenergic neurotransmission 1, 3
- Patients will notice immediate therapeutic effects from Vyvanse (within hours to days), contrasting sharply with guanfacine's delayed 2-4 week onset 1, 3
- Lisdexamfacine is described as clinically complete and effective in improving ADHD symptoms with a good safety profile 3
- The cross-taper approach minimizes the risk of symptom exacerbation during the transition while safely discontinuing guanfacine 1, 4
Common Pitfalls to Avoid
- Do not abruptly stop guanfacine even when starting a highly effective stimulant—rebound hypertension risk remains 1, 2
- Do not restart guanfacine at full dose if multiple doses are accidentally missed during the taper—contact healthcare provider for guidance 1
- Avoid evening dosing of Vyvanse as it may cause insomnia, unlike guanfacine which was preferably dosed in the evening 1