Sublingual Vitamin D3 Effective In A Patient Resistant To Conventional Vitamin D Supplementation

Abstract

Objective: Vitamin D deficiency is prevalent worldwide and is usually treated with oral supplementation. Bioavailability of vitamin D may differ among individuals due to variable absorption and metabolism in the body. Methods: A 66-year-old woman presented for evaluation of low 25-hydroxyvitamin D (25[OH]D) level. She had no known prior history of gastric or intestinal surgeries or malabsorptive conditions. She had previously been treated with oral vitamin D₃ at 2,000 IU daily with poor response. She was then treated with oral vitamin D₂ at 50,000 IU weekly, with persistently low 25(OH)D level at 14 ng/mL after 8 weeks of treatment. Results: Celiac screen was negative and duodenal biopsy was normal. Due to demonstration of poor oral absorption, she was prescribed vitamin D₂ at 50,000 IU sublingually for 8 weeks and then changed to over-the-counter vitamin D₃ drops sublingually (1,000 IU/drop) at 4,000 IU twice daily due to suboptimal response with vitamin D₂. 25(OH)D level improved gradually to 28 ng/mL after 12 weeks on this regimen and was at 37 ng/mL at 1 year. Conclusion: Sublingual vitamin D₃ may be an effective alternative mode of vitamin D supplementation in patients who demonstrate poor oral vitamin D absorption despite adequate supplementation for various reasons.