What is the recommended supplementation schedule for an adult patient with Attention Deficit Hyperactivity Disorder (ADHD) taking Vyvanse (lisdexamfetamine) who also has iron deficiency and requires vitamin D, calcium, and vitamin C supplementation?

Supplementation Strategy for ADHD Patient on Vyvanse with Iron Deficiency

For an adult with ADHD on Vyvanse who has iron deficiency and requires vitamin D, calcium, and vitamin C supplementation, take 100 mg elemental iron (as ferrous sulfate or fumarate) with 250-500 mg vitamin C in the morning on an empty stomach on alternate days, separate calcium (1200 mg daily, divided into 600 mg doses) from iron by at least 2 hours, and take vitamin D3 2000-4000 IU daily with calcium. 1, 2, 3

Iron Supplementation Protocol

Dosing and Timing

• Take 100 mg elemental iron once daily in the morning when hepcidin levels are lowest, which maximizes absorption 1, 2, 4
• Consider alternate-day dosing (every other day) as this may be equally effective with better tolerability, since iron doses ≥60 mg stimulate hepcidin elevation that persists 24 hours and reduces absorption of subsequent doses 5, 4
• Always take iron on an empty stomach for maximum absorption, though if gastrointestinal side effects are intolerable, taking with small amounts of food is acceptable to improve adherence 1, 2

Formulation Selection

• Use slow-release ferrous sulfate or ferrous fumarate as the most effective and tolerable supplements 6, 2
• Iron bisglycinate is an alternative if traditional iron salts cause intolerable side effects 1, 2
• Continue supplementation for 3 months after correction of iron deficiency to replenish stores 2

Vitamin C Co-Administration

Dosing Strategy

• Take 250-500 mg vitamin C (or 80 mg minimum) with each iron dose to enhance absorption, as vitamin C is the most potent enhancer of non-heme iron absorption 1, 2, 4
• Practical alternatives include taking iron with orange juice (one small glass provides ~80-90 mg vitamin C) 1, 4
• Do NOT exceed 500 mg vitamin C daily if you have any iron overload conditions or hemochromatosis, as vitamin C accelerates iron mobilization and can cause cardiac complications including sudden death 1, 2

Mechanism and Importance

• Vitamin C forms a chelate with iron that prevents formation of insoluble iron compounds and reduces ferric to ferrous iron, significantly improving absorption 1
• This is particularly critical since non-heme iron (from supplements) has only 1-15% bioavailability compared to 15-40% for heme iron from meat 1

Calcium Supplementation

Dosing and Timing

• Target 1200-1500 mg calcium daily from food and supplements combined 6, 3
• Divide calcium into doses of no more than 600 mg each, taken at least 2 hours apart, as the gut cannot absorb more than 500-600 mg at once 6, 3
• Separate calcium from iron by 1-2 hours since calcium inhibits iron absorption 1, 2, 3

Formulation Selection

• Use calcium citrate rather than calcium carbonate, especially if taking acid-reducing medications, as citrate is better absorbed 3
• Most calcium supplements contain vitamin D, which improves intestinal calcium absorption 6

Vitamin D Supplementation

Dosing

• Take 2000-4000 IU vitamin D3 daily to maintain serum 25-hydroxyvitamin D levels >30 ng/mL (>75 nmol/L) 3
• Vitamin D can be taken with calcium supplements since vitamin D improves calcium absorption 6, 3

Rationale for ADHD Patients

• Patients with ADHD may have lower vitamin D levels, and supplementing deficiencies may be a safe and justified intervention 7
• Vitamin D has important roles in neurologic function including involvement in neurotransmitter synthesis 7

Practical Daily Schedule

Morning (on empty stomach)

• Iron 100 mg + Vitamin C 250-500 mg (or with orange juice)
• Wait 30-60 minutes before eating breakfast
• Avoid coffee within 1 hour of iron, as coffee decreases iron absorption by 54% 1, 4

With Breakfast or Mid-Morning (2+ hours after iron)

• Calcium 600 mg + Vitamin D 2000-4000 IU

Afternoon/Evening (2+ hours after iron)

• Calcium 600 mg (second dose to reach 1200 mg daily total)

Alternative Schedule (Alternate-Day Iron Dosing)

• Days 1,3,5,7: Iron + Vitamin C in morning
• Days 2,4,6: Skip iron, take both calcium doses with vitamin D
• This approach may provide equal total iron absorption with fewer side effects 5, 4

Critical Pitfalls to Avoid

Timing Errors

• Never take iron with coffee or tea, as these are powerful inhibitors of iron absorption 1, 4
• Never take iron with breakfast (especially if it includes coffee), as this decreases absorption by 66% even with vitamin C present 4
• Never take iron in the afternoon after a morning dose, as circadian hepcidin increase is augmented by morning iron and persists 24 hours 5, 4

Interaction Errors

• Never take calcium and iron together, as calcium significantly inhibits iron absorption 1, 2, 3
• Never exceed 500 mg vitamin C if you have any history of iron overload, as this can cause life-threatening cardiac complications 1, 2

Monitoring

• Recheck hemoglobin and ferritin at 3 months, 6 months, and 12 months to assess response and adjust supplementation 2, 3
• Screen for possible deficiencies by checking ferritin, 25-OH vitamin D, and consider RBC-magnesium and serum zinc in ADHD patients at high risk 7

Evidence Quality Note

The strongest evidence comes from the American Gastroenterological Association guidelines recommending vitamin C as Best Practice Advice for iron supplementation 1, 2, and recent high-quality research demonstrating that alternate-day dosing with vitamin C in the morning maximizes iron absorption 5, 4. The calcium and vitamin D recommendations are based on National Osteoporosis Foundation and American College of Sports Medicine guidelines 6, 3.