Can Magnesium Be Taken with Vyvanse?
Yes, magnesium can generally be taken concurrently with Vyvanse (lisdexamfetamine), but timing and formulation matter significantly to avoid reducing Vyvanse's effectiveness.
Key Considerations
Absorption Interactions
The primary concern with concurrent use relates to magnesium oxide specifically, which can reduce absorption of basic drugs like amphetamines. Research demonstrates that magnesium oxide increases gastric pH, which decreases the solubility and absorption of lipophilic basic compounds 1. Since Vyvanse is a prodrug that converts to dextroamphetamine (a basic drug with pKa around 9-10), magnesium oxide could theoretically reduce its bioavailability.
However, this interaction is most problematic when medications are taken simultaneously. The FDA label for Vyvanse lists magnesium stearate as an inactive ingredient in both capsule and chewable tablet formulations 2, indicating that magnesium itself is not contraindicated.
Practical Recommendations
To safely combine these medications:
- Separate administration times: Take magnesium supplements at least 2-3 hours apart from Vyvanse
- Avoid magnesium oxide formulations if possible when taking Vyvanse, as this form most significantly affects gastric pH 1
- Prefer alternative magnesium forms: Magnesium citrate, glycinate, or other chelated forms are less likely to dramatically alter gastric pH
- Take Vyvanse in the morning (as prescribed: 20-30 mg starting dose, titrated to maximum 70 mg daily) 3, and consider taking magnesium supplements in the evening
Potential Benefits
Interestingly, research suggests magnesium may have beneficial effects in the context of stimulant use:
- Dextroamphetamine treatment actually increased plasma magnesium levels in hyperactive boys after 3 weeks 4
- Magnesium administration can decrease the intensity of amphetamine-induced dependence through modulation of glutamatergic synapses 5
- The calcium-to-magnesium ratio decreased with stimulant treatment, which may be relevant to side effects 4
Monitoring Requirements
When combining these medications:
- Watch for reduced Vyvanse efficacy if taken together, particularly with magnesium oxide
- Monitor for common Vyvanse side effects that magnesium won't prevent: decreased appetite, insomnia, dry mouth, anxiety, increased heart rate 2
- Be aware of serious warnings: cardiovascular effects, psychiatric symptoms, growth suppression in children, and peripheral vasculopathy 2
Clinical Context
The FDA label does not list magnesium as a contraindicated medication or significant drug interaction 2. The main documented interactions involve serotonergic drugs, MAOIs, and CYP2D6 inhibitors—not magnesium supplements 2.
Bottom line: Magnesium supplementation is compatible with Vyvanse therapy when properly timed and when avoiding high-dose magnesium oxide formulations taken simultaneously with the stimulant medication.