Can Vyvanse Be Taken With DMSA?
Yes, Vyvanse (lisdexamfetamine) can be taken concurrently with DMSA (dimercaptosuccinic acid/succimer) as there are no known pharmacokinetic or pharmacodynamic interactions between these medications.
Mechanism and Rationale
DMSA is a heavy-metal chelating agent used primarily for lead poisoning treatment that works by binding to heavy metals in the body, particularly in the kidneys where it accumulates and is metabolized to cysteine conjugates 1, 2.
Lisdexamfetamine is a prodrug stimulant that remains pharmacologically inactive until enzymatically hydrolyzed primarily by red blood cells to release active d-amphetamine and the amino acid lysine 3, 4.
These medications operate through completely independent mechanisms with no overlapping metabolic pathways, receptor targets, or elimination routes that would create clinically significant interactions 2, 5.
Pharmacokinetic Considerations
DMSA is absorbed through active transport in the GI tract, undergoes enterohepatic circulation, and is primarily protein-bound to albumin in plasma, with extensive renal metabolism occurring in proximal tubule cells 2.
Lisdexamfetamine conversion to d-amphetamine occurs in the blood and is unaffected by gastrointestinal pH or transit times, making it unlikely to interact with DMSA's absorption or metabolism 5.
DMSA excretion is predominantly renal (10-25% of dose within 24 hours as cysteine conjugates), while amphetamine metabolism involves hepatic pathways, further reducing interaction potential 2.
Clinical Monitoring Parameters
Continue standard ADHD symptom monitoring for Vyvanse efficacy, including assessment at 13-14 hours post-dose to ensure adequate duration of effect 3, 5.
Monitor for typical stimulant adverse effects including decreased appetite, insomnia, abdominal pain, and irritability, which are mild to moderate and transient 5.
Track DMSA chelation efficacy through blood lead levels and urine lead excretion, which typically shows 5-20 fold increase over baseline during treatment 2.
Watch for DMSA-specific adverse effects including transient transaminase elevation (up to 60% of patients) and skin reactions (approximately 6% of patients), though these rarely require discontinuation 2.
Important Clinical Caveats
No dose adjustments are necessary for either medication when used concurrently, as their pharmacokinetic profiles do not overlap 2, 3, 5.
DMSA may increase urinary excretion of copper and zinc, but not to clinically significant levels that would affect overall nutritional status or interact with stimulant therapy 2.
The combination is particularly relevant in pediatric populations where both lead poisoning and ADHD may coexist, and both conditions require treatment without delay 6, 2.