Children's migraines cut further by adding weekly vitamin D to topiramate (500,000 IU ?) - RCT

Efficacy of Topiramate Alone and Topiramate Plus Vitamin D3 in the Prophylaxis of Pediatric Migraine: A Randomized Clinical Trial

Iranian Journal of Child Neurology, Autumn 2020; 14(4): 77–86, https://doi.org/10.22037/ijcn.v15i1.18017

Razieh Fallah, Saeedreza Sarraf Yazd, Seid Mojtaba Sohrevardi

Summary by Claude Opus 5.5 - November, 2026

Children with migraine had fewer attacks when vitamin D3 was added to topiramate, the usual preventive drug: about 6 attacks a month vs 10 with topiramate alone, after two months.

This was a small randomized trial in Yazd, Iran. 60 children aged 5–15 enrolled and 57 finished (28 on topiramate alone, 29 on topiramate plus vitamin D). All had 25(OH)D above 30 ng/mL at the start, so none were deficient. Both groups took topiramate 2 mg/kg/day for 60 days. The vitamin D group also took "one 500,000 IU vitamin D3 pearl weekly." There was no separate loading dose and no placebo, and 25(OH)D was not reported after treatment.

The 500,000 IU dose is almost certainly a misprint for 50,000 IU (about 7,000 IU a day). Iran's standard high-dose pearl is 50,000 IU, and no 500,000 IU capsule appears to be sold anywhere Iranian vitamin D forms. The trial registry repeats the same number IRCT registry.

Results after treatment, vitamin D group vs topiramate alone:

  • Monthly migraine attacks: 6.1 vs 9.9 (P=0.01)
  • Disability score (PedMIDAS): 19.2 vs 22.1 (reported P=0.02)
  • Attacks cut by more than half: 75.9% vs 60.7% (reported P=0.01)
  • Severity and length of attacks: no difference
  • Side effects: mild and short-lived, 17% vs 14%

What this does NOT show / limitations

  • Open-label with no placebo; only the staff measuring outcomes were blinded
  • Small, one center, only 2 months, with no follow-up after stopping
  • The vitamin D blood level reached is unknown
  • Reporting errors: recalculated from the paper's own numbers, the "cut by more than half" difference (17/28 vs 22/29) gives P≈0.2 and the disability difference P≈0.14, so neither is significant. Only the drop in attack frequency holds up.
  • Attacks were compared after only 8 weeks, with no loading dose. If the dose was 50,000 IU weekly, blood levels were probably still rising (this takes about 3 months), so any benefit may be underestimated.
  • The children were not deficient, so results may differ in deficient children

PDF

Study was cited 25 times in Google Scholar as of Nov 2026


Related in VitaminDWiki

Headaches

Large Doses of Vitamin D

Note:
- VitaminDWiki had 400,000 capsules of vitamin D and placebos made for use in an adult COVID trial in 2020, but trial was cancelled