Effectiveness of weekly ergocalciferol 40,000 IU versus 80,000 IU in chronic myofascial pain syndrome and vitamin D deficiency: A randomized, single-blind, active-controlled trial

BackgroundVitamin D deficiency is prevalent in patients with chronic myofascial pain syndrome (MPS) and has been proposed as a potential medical precipitating factor. However, no clinical trials have compared different vitamin D supplementation doses in patients with chronic MPS and vitamin D deficiency.ObjectivesThis study aimed to compare the effects of weekly ergocalciferol 40,000 IU (standard dose) and 80,000 IU (high dose) on serum 25(OH)D levels and clinically meaningful pain reduction.MethodsIn this randomized, single-blind, active-controlled trial, 70 patients were randomly assigned to receive high-dose (n = 35) or standard-dose (n = 35) ergocalciferol for 8 weeks. The primary outcome was the proportion achieving optimal serum 25(OH)D (≥30 ng/mL). Secondary outcomes included ≥30% pain reduction and symptomatic adverse effects. Multiple imputation was used to handle missing data.ResultsAt week 8, mean serum 25(OH)D was higher in the high-dose group than in the standard-dose group (46.6 ng/mL; 95% CI, 40.6-52.7 vs. 34.4 ng/mL; 95% CI, 30.9-37.9). However, the high-dose regimen did not significantly increase the odds of achieving optimal serum 25(OH)D (aOR, 3.23; 95% CI, 0.77-13.42) or ≥30% pain reduction (aOR, 1.17; 95% CI, 0.33-4.10). Clinically meaningful pain reduction occurred in 75.8% and 66.7% of the high- and standard-dose groups, respectively. No symptomatic adverse effects were reported in either group.ConclusionAlthough the 80,000-IU weekly regimen resulted in higher serum 25(OH)D levels, it did not demonstrate a significant advantage over the 40,000-IU weekly regimen in achieving optimal vitamin D status or clinically meaningful pain reduction after 8 weeks.