What are the guidelines for giving magnesium supplements to children, particularly those with conditions like Attention Deficit Hyperactivity Disorder (ADHD) or asthma?

Magnesium Supplementation in Children

Magnesium supplementation in children should be reserved for documented deficiency states or specific acute medical emergencies (severe asthma, arrhythmias), with routine supplementation for ADHD not supported by current pediatric guidelines and potentially dangerous due to narrow therapeutic windows in young children. 1, 2, 3

Established Clinical Indications

Acute Emergency Use

• Severe refractory asthma: 25-50 mg/kg IV/IO (maximum 2g) given over 15-30 minutes for status asthmaticus unresponsive to standard bronchodilator therapy 1
• Torsades de pointes ventricular tachycardia: 25-50 mg/kg IV/IO (maximum 2g) given as bolus for pulseless torsades or over 10-20 minutes if pulses present 1
• Documented hypomagnesemia: Same dosing as above, with calcium chloride available to reverse potential toxicity from rapid infusion causing hypotension and bradycardia 1

Parenteral Nutrition Requirements

The ESPGHAN/ESPEN guidelines provide weight-based magnesium requirements for children requiring parenteral nutrition 1, 2:

• Preterm infants (first days): 0.1-0.2 mmol/kg/day (2.5-5.0 mg/kg/day) 2
• Growing premature infants: 0.2-0.3 mmol/kg/day (5.0-7.5 mg/kg/day) 2
• Infants 0-6 months: 0.1-0.2 mmol/kg/day (2.4-5 mg/kg/day) 2
• Infants 7-12 months: 0.15 mmol/kg/day (4 mg/kg/day) 2
• Children 1-18 years: 0.1 mmol/kg/day (2.4 mg/kg/day) 2

Critical caveat: Preterm infants whose mothers received magnesium sulfate therapy (for preeclampsia or tocolysis) may have elevated magnesium levels and limited renal excretion capacity in the first week of life, requiring dose adjustment based on serum levels 1, 2

ADHD and Magnesium: Evidence vs. Guidelines

The Research Evidence

While older research studies from the 1990s-2000s suggested potential benefits of magnesium supplementation in children with ADHD and documented magnesium deficiency 4, 5, 6, these findings have not been incorporated into current pediatric practice guidelines. One study used 200 mg/day for 6 months in children aged 7-12 years with documented deficiency 4, and another used 6 mg/kg/day with vitamin B6 for 8 weeks 6. A more recent 2021 trial showed behavioral improvements with 6 mg/kg/day magnesium plus vitamin D supplementation 7.

The Guideline Reality

No major pediatric guideline (AAP, ESPGHAN/ESPEN, or KDOQI) recommends routine magnesium supplementation for ADHD. 1, 2 The absence of this indication from authoritative guidelines, despite decades of available research, suggests insufficient evidence for routine clinical implementation.

Safety Concerns Outweigh Unproven Benefits

Commercial magnesium products (especially gummies) contain 50-200 mg elemental magnesium per serving, representing 2-8 times the physiologic requirement for a typical toddler 3. This creates serious risk because:

• Young children have higher body-surface-to-mass ratios, increasing vulnerability to systemic toxicity 3
• Renal excretion capacity is limited in young children 3
• Excessive magnesium can cause muscle weakness, respiratory depression, cardiac dysfunction, and death 3
• The FDA recommends children under 6 years only use magnesium products under medical supervision 3

Chronic Kidney Disease Context

For children with CKD stages 1-5 or post-transplant, magnesium management differs 1:

• Hypomagnesemia is common post-transplant due to calcineurin inhibitors (cyclosporine, tacrolimus), requiring supplementation 1
• Dietary magnesium intake should be encouraged first, but supplements are typically required to correct serum levels 1
• Calcium and vitamin D intakes should be at least 100% of DRI, but total calcium from all sources should not exceed 200% of DRI 1
• Normal serum magnesium range for newborns is 0.7-1.5 mmol/L (higher than adult ranges) 1, 3

Practical Recommendations

For documented magnesium deficiency requiring oral supplementation 8:

• Magnesium chloride 10% solution: 1.0 mL/kg/day (0.5 mmol/kg/day) for extended periods
• Magnesium gluconate (Magonate): 1.0 mL/kg/day (0.45 mmol/kg/day)
• Higher doses may be required for malabsorption syndromes
• Monitor serum magnesium, calcium, and potassium levels regularly 3, 8

For ADHD specifically: Standard evidence-based treatments (behavioral therapy, stimulant medications when appropriate) should be prioritized over unproven magnesium supplementation. If magnesium deficiency is documented through laboratory testing, supplementation may be considered under medical supervision, but this addresses a comorbid deficiency rather than treating ADHD itself 4, 5, 6, 7.

Key Monitoring Parameters

When magnesium supplementation is medically indicated 3, 8:

• Serum magnesium levels (normal 0.7-1.5 mmol/L in young children)
• Serum calcium and potassium levels
• Renal function assessment before and during treatment
• Clinical signs of hypermagnesemia (hypotension, bradycardia, respiratory depression, muscle weakness)